Flooded, AGM, Lithium. Which battery is best? Well, we recently tested all of these in laboratory-controlled conditions. We determined the real-life performance and lifetime costs of each to share with you which is the best RV battery out there.
An Unexpected Opportunity
We visited Reno, Nevada where Battle Born Batteries are manufactured. While there we had the opportunity to interview the founders of the company.
The primary purpose of the interview was to discuss a White Paper they had published earlier in the year about cold weather charging lithium-ion batteries. The paper included a bunch of data comparing lead-acid AGM batteries and lithium-ion discharge characteristics in both warm and cold temperatures.
We made a video about this white paper and got lots of feedback. I took the opportunity to ask CEO Dr. Denis Phares and COO Sean Nichols many of the questions that were posed to us.
At one point during the interview, Nichols started talking about battery capacities. He said the lead-acid battery companies have such stringent battery parameters that it’s nearly impossible to get the capacity ratings they tout. He told me that an RVing family will not be able to get 50% of the battery power out of their lead-acid RV batteries like they’ve been told.
Battery Testing Invitation
I questioned this further and asked if I could see the testing setup they used. In response, Nichols offered for me not only to see it but to come and replicate or run my own experiments. We had some more time in the area, so I decided to take him up on this opportunity.
I’m a bit of a nerd, and also an electrical engineer with a background in Power Systems and battery storage systems for both residential and commercial backup power applications. While I have installed many Power Systems, I have not done much load testing on batteries. This seemed like it would be a neat opportunity to find out once and for all what the best RV battery is – both in terms of performance and cost-effectiveness.
What’s Important In The Best RV Battery?
RVs are used in all types of temperatures and weather conditions. RV batteries are a critical part of the power system, with many appliances requiring a charged battery to function property.
The best RV battery will first of all be getting the energy out of it that it says we will. It will also be able to function at different temperatures, as RVers are never in a vacuum. Finally, it will be cost-effective over its lifetime.
The Battery Testing Setup
I told them that the experiments would need to be run with my own parameters for me to do the testing. They agreed not only to this but also to let me rebuild the testing set up with their engineers. So, we got to work.
We built two identical test setups that would feed data into a single data-logging computer.
Equipment Components & Data Logging
The setup was built with a Victron Energy Multiplus Compact 12V 2000kVA 80A inverter/charger used for charging the batteries. 2/0 Cable connected the batteries and the inverters as well as connecting to a set of resistors that can be configured for either an 8 or 80 amp discharge.
A voltage relay controlled the main disconnect relay that we could set or low voltage cut out. An external 24-volt power supply supplied power to the relay was supplied so as not to impact the battery’s discharge.
During each test, both current and voltage were continuously recorded using a National Instruments NI USB-6210 data acquisition system (DAQ) at 1Hz intervals. Voltage dividers with low variant resistors were used to ensure that the voltages conformed with the limits of the DAQ. An AcuAMP DCT 200-10B-24S DC current transducer was used to convert the charge and discharge currents to voltages that could be monitored by the DAQ.
We used two identical freezers with temperature sensors to control the temperatures of the batteries for all tests.
main battery switch voltage cutout relay controller main negative busbar wiring A shot of the two test benches
Batteries For Testing
As the purpose of this test was mainly to evaluate different lead-acid batteries vs. lithium-ion to determine the best RV battery, we acquired 4 different types of lead-acid batteries. These ranged from high-end AGM batteries commonly used for high-performance vehicles and RVs, down to cost-effective AGM and flooded lead-acid batteries that can be procured at most national battery retailers.
While Battle Born Batteries’ original cold temperature study only used 2 lead-acid batteries versus 2 lithium-ion batteries, we decided to test a bank of 4 lead-acid batteries against 2 lithium-ion batteries. We thought this would be a more fair representation of lead-acid vs. lithium-ion batteries. By testing four lead-acid batteries, the current would be half of that of the lithium batteries giving them a better chance with the Peukert effect.
As we are not trying to bash any particular battery, we will not disclose the exact brand of batteries used. However, the following data showcases the cost, rated capacity at 20-hour discharge (for the lead-acid), recommended cutoff voltages from the manufacturers, and expected life cycles from the manufacturers.
AGM 2 Flooded BB10012 Heated BB10012 AGM 1 That’s a lot of batteries!
Energy Data
By getting to define the testing parameters, I was able to make sure we collected enough data to get what I deemed most important. What I am most interested in is the actual energy the batteries can provide.
Amp-hour data is a rating of power and not necessarily directly related to energy as voltage can fluctuate. My goal with these tests was to figure out how much energy each battery delivered under different circumstances.
Comparing energy in Watt Hours will give us an “apples to apples” comparison of each battery test. This allows us to take a look at actual $/Energy or $/Watt calculations to determine which RV battery type is the most cost-effective to own.
Running The Tests
Each test began with fully charging the batteries to their recommended full charge per the manufacturer’s instructions. All lead-acid batteries were allowed to get through their absorption cycle and into float which was usually an overnight charge.
Data logging was begun before tests began and ran after testing to record the voltage bounce back of the batteries. At a 1Hz cycle, we are accurately able to calculate the Amp Hour and Watt-hour capacities that the batteries provided.
Room Temperature Testing
Tests were first performed at room temperature – 70 degrees Fahrenheit. The lithium-ion batteries were discharged to their 100% cut off voltage of 11.8. The lead-acid batteries were first discharged at the recommended 50% cutoff voltage, which is 12.2 volts for the AGMs.
The second set of tests was conducted dropping them to their 80% recommended cutoff voltage at 11.8.
All of these tests were conducted at first an 8 Amp slow discharge. The tests were then run again at an 80 amp fast discharge.
Cold Temperature Testing
Once the room temperature test was completed, the freezers were turned on and dropped to 10 degrees Fahrenheit. All the batteries were tested once again at both the 8 Amp and 80 amp discharge at 10 degrees Fahrenheit.
For sake of time, these tests were all run at 11.8 volts cut off. But by integrating the data, we are able to extrapolate a 12.2 volt cut off amp-hour and watt-hour measurement.
One additional battery was added to the cold temperature test: the newly released Battle Born Heat Battery. This battery has internal heating elements that warm it to the appropriate operating temperature for discharge and charging.
Batteries were charged at 10 degrees F using the same charge profiles as was tested at room temperature. The BB10012 could not be charged at 10F and was brought up to 25F for charging. The BB10012H heated battery was charged in the cold and allowed to remain on and heating itself for 8 hours prior to a discharge.
A second cold-weather test was performed on AGM1 and AGM2 sets at 25 degrees F. We modified the charge parameters to account for the cold temperatures per the manufacturer’s instructions. This is rarely done by a consumer, but we wanted to compare test data against Battle Born’s original 25F data with temperature compensation for charging.
Real World Cold Temperature Testing
Battle Born’s original paper made it look as if most AGM batteries would not work in the cold if set to 12.2 cutoffs. We wanted to see how true this would be, so we charged up the AGM2 set of batteries and plugged in a microwave and coffee maker to the inverter.
We ran these appliances off the cold batteries and watched the load and voltage of the batteries.
9V Drain Test
When we were nearing the end of our time, there was one additional test we wanted to run, which was discharging the batteries all the way down to 9V. This test took a long time to run and we only had time for one set, so we chose the most cost-effective lead-acid batteries, the AGM3, and Flooded set.
This test was run to see how much capacity the batteries could make. The true 50% and 80% of discharge points were extrapolated from the data. The voltage recovered was recorded, too.
Results
We will get into the analysis of each test below, but here are some of the main takeaways from the data.
#1. None of the lead-acid batteries made their rated capacities at the stated cut off voltages from the manufacturer. Even at room temperature with extremely low discharge rates below their 20-hour rate.
#2. The lithium-ion batteries’ performance exceeded their rated capacity at all discharge rates.
#3. The cost per watt-hour delivered for lead-acids was surprising. It was much worse for the expensive AGM batteries than the cheaper options. The flooded lead-acid was the cheapest under all circumstances.
#4. The lifetime cost of all the lead-acid batteries is 2 to 6 times higher than the lithium batteries. Over the life of your RV, this battery is the best.
#5. Lead-acid batteries deliver less power than lithium for the same Amp-hour because of the deeper voltage sag.
#6. The lead-acid batteries have such a high voltage sag in the cold. It’s hard to get power out of them at high loads without lowering the voltage cut-out. Cold weather voltage compensations need to be made to the charging profiles for lead-acid batteries to get acceptable performance in the cold. For the average RVer, this is a bit ridiculous to expect them to do.
#7. Heated lithium-batteries work great! They will self consume some of their energy, so we recommend insulating them for the best results.
Data Files For Your Own RV Battery Analysis
Now let’s take a look at how we arrived at these results with each test. At the end, I will be sharing my recommendations on the best RV battery.
If you wish to review the data or run your own analysis, here is a link to most of the raw test data. This is a VERY big file with millions of data points and your computer may hate you for working in it. It has crashed multiple computers so you have been warned 😉
Room Temperature Capacities
Personally, I think these are the most interesting of the tests we ran. I expected to learn the most from the cold tests, but this data surprised me the most.
Lithium-Ion Battery Capacity
The lithium-ion batteries were tested only once taking them down to their recommended 100% cutoff at 11.8V. These batteries outperformed their rated capacity at the 8A and 80A discharge rates, coming in at 108% and 102% respectively. It feels good to get more than what you pay for. 🙂
Lead-Acid Battery 50% Cutoff Capacities
For the lead-acid batteries, let’s first take a look at the battery capacities we calculated at the different cut off voltages. All of the AGM batteries had a recommended 50% cutoff voltage at 12.2V and the Flooded had a 50% cut of 12.0V.
- Using the 50% cutout, none of the lead-acid batteries were able to make their 50% rating.
- Interestingly, the most expensive AGM (AGM1) performed the worst only making 32% of their rated capacity at the low draw test and 16% at an 80A draw.
- The cheaper AGM 2 batteries could not run the 80A load for long at all before the voltage sagged and the system shut down.
- Using the 12.0V 50% cut for the cheap flooded Lead-acid batteries they almost made their rating at 47% performing the best at the rated 50% test.
One interesting thing to note is that the lead-acid batteries at a 50% cutout made less power than the 2 Lithiums that are rated for full discharge. This will come into play later when we look at the actual cost of energy production.
Lead-Acid 80% Cutoff Capacities
Next, we ran a test down to 11.8V which is the 80% cut out for the AGM batteries. Here is what we found:
- Once again, none of the batteries made their ratings.
- The expensive AGM batteries performed the worst in the low discharge test.
- At this discharge, the 4 AGM batteries did make more power than the 2 lithium batteries, however, discharging them this low will significantly impact their life cycles as evident in the batteries data table above.
Energy Discrepancy
I did a quick calculation integrating the data from the 11.8V discharge of the AGM3 batteries to the point when they hit 216 AH capacity – the same capacity as the lithium batteries’ full discharge. Then, I integrated out the calculated watt hours to the same AH discharge of the Lithium.
It was interesting to see that the lithium batteries delivered more energy at 2808 watt-hours at 216AH compared to 2683 Watt-hours of the AGM batteries at 216AH. This is not a huge difference, but I think because the lithium battery maintains its voltage at a higher state for longer it delivered more power.
As stated before, amp hours are not energy and different batteries will provide different energies at the same Amp hour rating. I say it all the time, but I would like to see energy storage batteries rated in Watt-hours, not amp-hours. This is once again another win for the lithium-ion batteries, but we can take this a step further and negate amp-hours altogether and calculate the actual cost per Kwh of each battery.
Voltage Recovery
According to the lead-acid battery manufacturers, there is only one way to get an accurate state of charge estimate. This is from a steady-state voltage after completely disconnecting the load and allowing the batteries to sit for a few hours.
Because this is absolutely not a real-world thing anyone does, we did not do this either. But, we did record for about half an hour after the tests to get an idea of the voltage recovery.
For the low current tests, voltage recovery was not much more than .1 volts so our tests should be very accurate. For the 80A discharge voltage recovery was frequently .4 to .5 volts. Because of this, an 11.8V discharge was probably close to a 12.2V true discharge once the load was removed.
This is an inherent problem with batteries with deep voltage sag. We can either lower the voltage to allow the inverter to work longer and risk damaging the batteries, or leave it at a higher cutoff voltage and miss out on power for larger loads. To address this, you must well oversize lead-acid battery banks to distribute the current across more batteries and keep the voltage drop down.
Actual Battery Cost Per Energy Delivered (Room Temperature)
This is where things start to get interesting. These first calculations were strictly the cost as tested divided by the delivered energy (not over the life of the battery).
This calculation should be independent to battery bank sizes except in heavy load situations where the load will be distributed among more batteries.
From this data, we can see that if you are using a 12.2V cutout to meet the manufacturer’s 50% recommendation, the lithium batteries are actually cheaper than both the expensive AGM and only slightly more than the cheap AGM!
The cheap, flooded lead-acid batteries are clearly the winner on the cost-effective per energy delivered calculation a low 8A discharge. When taking a look at a discharge to 11.8, things get a bit better for the AGM batteries and the cheapest AGM performs at almost half the cost of the full discharge lithium.
High Load Discharge Cost
This is where lithium-ion battery technology really shines.
Because they exhibit so much less of the Peukert effect, they always deliver more energy at high discharge rates than a lead-acid alternative. This becomes clearly evident in the cost of running high discharges as well. Take a look at the rightmost column of the Cost Per Energy Delivered Table above.
Both expensive AGM performed so badly that the lithium is much more cost-effective.
Note: The $91 number for AGM2 came from the fact that the voltage sagged so badly under load that at 12.2 it cut out almost immediately. Surprisingly, the cheap AGM3 batteries performed okay along with the flooded 6V set in series.
Lifecycle Costs (Room Temperature)
After looking at the $/Wh cost results in the table above, it appears that the flooded lead-acid batteries are the most cost-effective battery to own, followed up by the cheapest AGM.
However, this does not account for the lifecycle of the battery and is only an instantaneous measurement.
Lifecycle is defined as how many times the battery can discharge before reaching its end of life (EOL). EOL from a battery manufacturer’s perspective is when the battery can only hold 80% of its original rated capacity. Manufacturers provide estimated cycles before this happens.
Here is the chart for these estimated cycles for each battery on the right-hand side for 50%, 80%, and 100% depth of discharge (DOD).
The lifecycles are heavily dependent on how deeply the battery is discharged. So, we can now take our data and calculate a lifecycle cost per battery with the following equation.
Lifecycle Cost per Watt Hour = Cost of batteries / (delivered Watt hour X Lifecycle numbers)
We ran this calculation (divided by 1k to get in Kilowatt hours instead of watt hours) and got the following results. This is where we find out which RV batteries we should be spending our money on!
Because of voltage recovery effects of lead-acid batteries, these numbers calculated at an 8 A discharge (2A per battery) should be an accurate representation of cost at a best-case scenario for lead-acid.
The Most Cost-Effective RV Battery
It is clear that lithium batteries are the cheapest to own over their life.
It is also interesting to see that the expensive AGM still remains expensive and provides no energy benefit at all. Seeing lithium as the cheapest option is exactly what I expected. But, I did not think it would be by this big of a margin being 2-6x less expensive.
As mentioned before, this is really the best-case scenario for lead-acid. It’s unlikely that the energies we got in the tests could be attained in real-world scenarios. Lead-acid is very sensitive to loads and charging. When not used per their specifications they perform even worse, so this is the best case data.
Real-World Lifecycle Tests Suggest Even Poorer Lead-Acid Performance
In addition, I procured some real-world test data from early tests performed by Battle Born Batteries against the same AMG 2 Battery Brand. These tests were performed at a 50A discharge (25A equivalent per battery), which is much higher than we ran but down to 11.8 or an 80% cutout.
It’s interesting to note that their data reflected an initial capacity around 140Ah, or about 60% similar to the numbers in our experiment. The battery in their experiment hit its 80% capacity at only 100 cycles with an 80% discharge. Note that they were not allowing for voltage recovery on a high discharge so it was not a true 80% discharge, and the life was still terrible.
If this is real-world performance (and likely usage by an RVer) then the lifecycle cost numbers will be much much higher than calculated.
Cold Temperature Battery Testing
In addition to running room temperature tests, I ran some cold temperature tests. The batteries were placed in freezers with plenty of airflows to make sure they got really cold.
This was also an opportunity to test out the Battle Born BB10012H Heated Battery. This battery has internally heated strips that keep the battery at optimal operating temperature for both charging and discharging.
10 Degree F Cold Temperature Testing
I had a limited amount of time to run the tests. So, we only ran 11.8V cut voltages and repeated the same tests that we ran at room temperature. This time we ran them at 10 degrees F, including the same charge parameters.
All of the batteries showed degraded performance in the cold. We see about a 20-25% loss across the board compared to their room temperature performance at a low discharge rate. When comparing at a higher discharge rate this percentage was much worse for the lead-acid batteries.
This is due to the Peukert Effect being exaggerated for lead-acid batteries in cold conditions. This was a key takeaway from Battle Born’s original cold temperature whitepaper.
Matt from Adventurous Way did a great write-up about their paper and this effect. He graphed out the capacity loss at load in cold weather, shown below. Matt has a degree in physics and is a really smart guy with whom I discussed these results in detail.
Read his analysis here: Battle Born Cold Charging Study: Analysis
Battle Born Heat Battery Performance
Taking a look at the Battle Born heated battery performance reveals some interesting data as well. The heated battery should have a very similar capacity to the standard 100Ah setup but actually gave us less discharge capacity at the low discharge rate. This was due to the batteries heating themselves and using some of their energy to keep warm.
The heat was turned on 8 hours prior to the test. The batteries were all completely uninsulated and spaced apart for best cold airflow. So, this was the worst-case scenario for the heated battery.
Regardless, it stayed warm and was able to be recharged as normal even in these cold conditions.
It performed better in the 80A test than the non-heated version because the runtime was so much shorter, it was less time that it was heating itself. The standard lithium battery could not be recharged in the cold to run the 80A test and had to be warmed up to 25 degrees to charge, then cooled off again.
For cold-temperature RVing, this is your the ultimate best RV battery choice.
25 Degree F Battery Testing With Charging Compensation
I wanted to give lead-acid the benefit of the doubt, so we warmed the batteries up to 25 degrees. This is a more likely RVing temperature. We also changed our charging parameters to compensate for the cold. This includes charging at a higher voltage per the manufacturer’s specification.
It is rare that users program temperature voltage charging compensation into their lead-acid systems, so this is an unlikely scenario. But we did it anyway. Interestingly, the batteries performed no better than the 10F discharge at the 8A slow discharge. But, they almost met their original room temp performance at the high discharge current.
Real-World Cold Temp Example
Before we were done with the cold temp tests, we wanted to see what would happen in a real-world cold temperature scenario. We charged the batteries one more time at 25F and set up some tests with a microwave and coffee maker – two tasks an RV battery might be asked to perform.
Using the inverters, we plugged in and put a load on the AGM3 batteries and logged their performance. We started with an 11.8V cutout and was only able to run the coffee maker for about 2 minutes before the inverter cutout. Then we dropped the voltage to 10.6 and continued the test and completed our coffee.
We then plugged in a microwave and ran for another 7 minutes, at which point it worked. When turning off the microwave the voltage bounced back to above 12.3 volts.
This showcased a real-world problem with the lead-acid batteries in the cold. The significant voltage drop needs to be compensated for to use the batteries. It’s safe to lower the voltage for short periods of time, but must be monitored occasionally at a steady-state so as not to drain them too far. Because of the cold temp Peukert change, even a shunt-based battery monitor will not accurately read the state of charge for cold lead-acid batteries.
9V Drop Test
In our final test, we allowed our most cost-effective lead-acid batteries to discharge way beyond the recommended stop points. We wanted to see if they could make their capacity. We used our 8A slow discharge and ran them down to 9V at room temp of 70F.
Note: This is never recommended for a lead-acid battery as it will damage it even with one discharge like this. Since these were test batteries, we went for it.
AGM3 9V Drop Performance
The AGM 3 batteries almost made their entire rated capacity coming in at 97.48 percent. After integrating the load data, I determined that the true 50% voltage was at 12.0V (should be 12.2 according to the manufacturer).
Unfortunately, these batteries only recovered to 10.9V which is well below the recommended steady-state voltage, so irreparable damage was done.
Flooded Lead-Acid 9V Drop Performance
The flooded lead-acid batteries cut out sooner, only providing 86% of their capacity and the 50% was calculated at 11.9V (12.0 according to manufacturer). These batteries recovered to 11.6 which is interesting that even at such a low load they didn’t fully discharge.
We could have run these tests lower than 9V but there really isn’t any point as 9 V is well below what any electronics should run at anyway.
Best RV Battery Testing – Conclusion and Recommendations
Truthfully, the data we acquired shocked me as I was gathering it. Nichols’ statements about not being able to achieve capacity seem true as all the lead-acid setups had trouble making their ratings. It would be hard to get them to perform any better in real-world situations.
Lead-acid batteries are too sensitive to environmental, load, and charging conditions to be used reliably in a power storage system. Compared to lithium-ion batteries, I can no longer recommend them.
I used to recommend them as a cheaper alternative, but after seeing the cost data even that does not make sense. The lifetime cost is so much more expensive than lithium – and that doesn’t even factor in replacement costs and labor.
When To Use Lead-Acid?
Lead-acid batteries do one thing very well, they provide great amounts of current for very short periods of time. As long as they are immediately recharged, they can have a good life. This makes them good for engine starting batteries and I don’t think they will be replaced any time soon (but it will eventually happen).
As for power storage, they are all terrible. Paying for expensive AGM or flooded batteries does not seem to get you any better performance and is a waste of money. If you truly cannot afford lithium, get the cheapest lead-acid batteries you can and save your money for lithium next time.
Consider, however, that you can get away with half the lithium capacity vs lead-acid and get even better performance, as seen in this study.
Cold Weather Use?
In cold weather, lithium still outperforms lead-acid and can be used, they just must be warmed prior to charging just like lead-acids. Heated batteries are a great way to get around this. We recommend insulating them so as not to waste energy keeping them warm. Lithium-ion batteries don’t need to be vented, so they can easily be installed in an enclosed space that’s easy to warm and not worry about them.
The Best RV Battery For The Money
Lithium-ion battery benefits have been understood for a long time, but they’ve always had the downside of “being more expensive.” Well friends, per our test results, this has been disproven. The best RV battery out there is also the most cost-effective over its life.
And that isn’t even factoring in the quality of life benefits of never having to buy/replace another battery or worry about state of charge again!
Technology marches ever forward and with it, batteries. It’s amazing that lead-acid has hung on as long as it has, but it’s truly an outdated technology for energy storage. These tests were the final nail in the lead-acid coffin for me. I will no longer be looking at or even considering lead-acid for anything other than starting batteries.
As they say at Battle Born, “Lead is Dead.”
If your interested in learning more about Battle Borns Products check them out here: Battle Born Batteries
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Hey Guys,
Just wanted to take a minute to say how grateful I am for your content, especially the info on solar. My wife and I are going full time in the spring. and your videos have helped in making our decision on the proper solar system for our needs. Thank you so much! Do you install solar systems? If so, I’d be interested in getting a quote from you.
So glad you are finding our content helpful! I no longer install solar systems as I just don’t have the time.
A lot of this is over even my fairly well educated head. But great info just the same!
One thing about lithium-ion is heat. More specifically the long term effect of use during hot temps. We all have read how they will work “fine” up to XXXF. I would love to see some real data on this meaning over time what can you expect? If average temps are 65F, 75F, 85F, 95F, 105F etc. My only point of reference is the Technomadia use case where their (albeit old) lithium-ion failed sooner than expected. They reference the possible cause as being in warm temps for a majority of the battery lives.
Great question Joe! Yes, high temperatures have a negative impact on lithium life. The Battle Borns don’t shut down until 130F but longevity is something to consider with any battery type. That is one of the main reasons for car batteries going bad in engines too. I did come across some data on temperature degradation in my research but did not analyze it yet. I will put that on the list for a future article, however!
Technomadia didn’t have good ventilation for their first lithium battery bank. Typically, you install Battle Borns inside, with good ventilation–which you shouldn’t do with AGMs (even though they are “sealed,” they do have vents for off-gassing if overcharged).
However, the notion that lithium is more sensitive to heat than AGM is incorrect. Trojan specifies an operating range of -4F to 113F. https://www.trojanbattery.com/pdf/AGM_Trojan_ProductLineSheet.pdf
Battle Born specifies a more accommodating range of -4F to 135F (with charging cutoff below 24F). https://battlebornbatteries.com/are-there-any-temperature-restrictions-on-your-lifepo4-batteries/
Imagine how hot it gets under an RV traveling through the South in summer, with heat from the engine and exhaust combined with driving over extremely hot asphalt. I’m pretty sure it is quite easy to exceed the 113F maximum for Trojan AGMs.
Great point. It was actually interesting that in the AGM manuals I found most of them did not recommend charging below freezing at all either.
Interestingly, I don’t have the kind of issues you described in your article primarily because I live in Hawaii, with temperate conditions that don’t vary much. It’s usually very warm here (avg. 90F) and I currently use 2 marine batteries of 600CCA ratings from Interstate for my power to my ham radio systems as well as an inverter to run a few things like lamps and a nebulizer compressor. I’ve not had any issues with these batteries (I usually replace them every 3 or 4 years when they begin to lose their capacity despite only having a 2 year warranty). They’re charged by 160W 12DC solar panels through a solar charger. I understand that Li-Ion requires a different kind of charger so wonder what they cost in order to use them with my setup, not to mention the cost of similar capacity batteries. My 2 batteries retail at about $250 total and spread over the average 3-4 year life is pretty cheap. I also worry about Li-Ion’s aversion to higher temperatures and the greater possibility of fire vs. lead-acid. Anyway, nice article and something to look into.
Tom, great information.
Most of the online information I’ve seen regarding LiFe batteries is based on Battleborn, its great they are so accessible, but I’m curious how the lower cost alternatives stack up. Can we assume that LiFe chemistry will perform similarly, I assume Lion Energy batteries should compare similarly to Lead acid, or even a custom assembled group of cells with BMS. Or will my investment on lower cost cells from AliExpress be another disappointment in the long run.
Yes and no, Cylindrical cells should have similar performance, but prismatic or pouch cells will still not have the longevity even if they perform the same upfront. Unfortunately, there is quite a bit of variation in cells so I will probably plan for future testing. The electronics are also important as a good BMS that will last the life of the battery is important. If its poorly designed with small FETS it will be much more susceptible to transients that can kill it. Terrible to have good cells and a dead BMS. Hopefully, I can do some testing on this in the future.
Good video. Ginger loved it but it was over my head. I can’t figure out why i need a heated battery. I thought the lithium had to be inside ( ours are going under the bed). If thats the case why heat them?
I am running two AGM batteries now but I can see that it will be better to run one lithium battery than what I now have. When I replace my batteries it will be with one Battle Born battery. I have watched several comparisons like this and I am convinced that the up front cost is money well spent and is cheaper over the life cycle of the battery. Hope I luck out and win these two. Thanks for the great video.
Have you ever compared Rv lithium-ion batteries? ( not just battle born) I’ve been looking on Amazon at all the other brands. Thank you!
I have some experience with a few different brands, but no have not gone head to head with them yet. I would like to do that in the future. I don’t any recommendations yet as the BMS is such an important part and I haven’t analyzed them. I would recommend sticking with a cylindrical cell battery however as opposed to prismatic or pouch cell for longevity.
Thank you for the information, looking to go full time and this will help us on our next purchase.
You’re welcome! Good luck with your full-time adventures!
Thanks for the in-depth testing! Most of the information goes over my head, but the fact that you and Battle Born offer the raw data to everyone underlines the results very well: LiFePO is worth the investment.
You’re welcome!
My stock rig has 2 AGMs under hood. They have made thousands of these Roadtreks. When it came time for replacements I needed sealed batteries as brake lines run close by and corrosion could be an issue. I talked to Battleborn and they advised to not use their batteries underhood due to high heat. Also, the surge capacity might not be enough to start my generator. Also I would probably need a new charge controller. I went with AGMs.
It’s always a good idea to do your homework before replacing batteries (or anything else!) on your rig. Sounds like you did just that! Hope your new batteries are working well for you. Thanks for reading!
Great test data Tom. The BattleBorn heated batteries are a great solution for us cold weather campers. Since their battery heater solution grounds internal to the battery I don’t see a way for a battery monitor system to track those amps used.
Good point, it wont. That could be a problem with the batteries in cold to get an accurate reading. I will bring this up with the BB engineers next time I talk with them. Sounds like we need internal battery monitoring.
Perhaps they could provide an external ground for the heating system. Running a short wire to chassis ground would do the trick. Thanks Tom.
What computer software did you use for the battery testing?
This was all run throught National Insturements software along with the DAQ – https://www.ni.com/en-us/shop/data-acquisition.html
I’m curious for your thoughts on cold weather storage of heated lithium batteries. Assuming minimal solar recharge but constant minimal draw for CO and propane detector which can’t easily be disconnected.
I would use the battery disconnect and completely disconnect the system with the batteries fully charged and turn the heat off (if using heated batteries). If temperatures are expected below -10 I would probably pull the batteries altogether if possible. Of course if they are heated batteries and they are plugged in you can just leave them on.
I love the fact that, after watching, what I have learned in the past about lithium was reinforced by you. It eases my mind. Because my son and I are homeless, “working homeless”, and I am going to be buying a RV trailer to tow behind a vehicle to live in. We desperately need to have a reliable power source in our situation. Once again, Thank You !… DeAnna Kline and Son.
Glad we could ease your mind about the lithium batteries! One less thing to worry about as you venture into RVing. 😉
Where do we find your link for ordering BB batteries?
I should add a link in the blog. https://battlebornbatteries.com/product-category/lifepo4-batteries/?afmc=1x.
I’m your charts it say the battery cost $900 which is what the website says too. But then you have other charts that says you paid $1600 for the 2 lithium batteries, which would mean you got them for $800 each. Saying that the average consumer will have to pay $900 each the chat for the set of 2 batteries should be $1800.
I’m concerned that your cost analysis is off on the lithium batteries since you used a figure that’s $200 lower than the actual cost of the batteries.
That’s a great point that was a mistake carried into this blog. The cost as calculated used the actual battery cost (see manufacturer battery chart costs) multiplied by the number so the calculations are correct. I will try and update that chart.
Very informative. Looking forward to reading the blog more often.
Thank you! 🙂
Really enjoyed your video comparing Lithium to Lead-acid batteries. A lot of this was way over my head, but my son who’s a Chemical Engineer and worked for a battery company in Chicago says Dah dad, you should have known this. But my background is IT and not Batteries. This video helped convince me to spend a little…or a lot extra on the Lithium-ion batteries. In the long run it will be cheaper. Tried to convince my son to help me build my own Lithium-ion batteries to reduce cost and he won’t even go there….Too much risk…safety-wise
We agree. Lithium batteries are cheaper over their lifespan. Glad you enjoyed the video! 🙂
Thanks Tom, I guessed what surprised me the most was how much actual usage I can get out of my 2 lead acid batteries that came with our 18 Jayco travel trailer. I know for sure now I won’t be boondocking anytime soon using those 2 2 year old lead acid deep cycle batteries that came with the RV. I will continue to use them as I can’t afford to replace right now. But I was very impressed BB funded and gave you full control over the experiment. That alone says alot about the company. Hope you and Cait have a happy New Year.
Bob and Janie Makowski
Thanks Guys! As long as you don’t over-discharge lead-acid they can still last a long time, especially with lighter use. I hope someday lithium just comes with campers and are a lifetime thing. Yea Battle Born is a pretty great company, I thought it was pretty bold to let me have full control over the experiment. They didn’t even know what I was going to release today! Lucky it worked out in their favor, or I guess confident.
Thanks Robert, you brought up a good point in Li vs lead acid. Many RV’rs aren’t concerned about making a battery last until the EOL. Few of them will own their rig long enough to go 5000 charges and discharges Li batteries can potentially get. We will keep our Sprinter van perhaps another 5 years. It has Trojan T105’s in them which will easily last that long. Our power needs are small so we don’t draw them below 11.8 ever. So purchasing 5X more expensive Li batteries just isn’t economically sensible. Even slightly more resale cost won’t make up the difference. Now on our next camper we might want to hook up the microwave and that would change the economics.
Its something to consider for sure, light loads and not using for any major power needs the li cost may be too high. I think the price will continue to come down however and it would sure be nice to never have to think about the RV’s battery!
Thanks for the info. I have watched several solar set ups and all are pretty consistent with the type of batteries, but this was the first time that the cost of the lithium battery was justified based on the number of cycles. Thanks for the info. I really tried to keep up and did understand most of the highpoints.
You’re welcome! Glad we could help you justify the cost.
we discovered Mortons on the Move in your Go North videos when the Covid lock down started. We were thoroughly entertained and are planning a RV caravan trip to Alaska in 2022. Sometimes you lose me on the technical side but thoroughly appreciate all of your in depth posts and videos.
Thanks for watching Go North and for reading our blog posts (even the technical ones!). 🙂
I am hoping to DIY van build as soon as the weather gets better. The info on the battleborn lithium batteries are what I needed to convince me to go lithium.
Awesome! Good luck with your van build!
Great review, huge in data. Well done. 2 years ago I decided to go withsilicone doxide (Si02) batteries. Around half the cost of lithium but with similar benefits. No off gassing, cold weather use and my fears of lithium battery overhat fires. Draw back is they require specific chargers and weigh the same as lead acid. I only carry three 100 A/hr due to the weight.
Thank you so much for the information you shared,peaked my interest in the lithium battery as i am in the market for batteries for my RV thanks again, VERY INFORMATIVE ⭐⭐⭐⭐⭐
You’re welcome! Glad it was helpful!
I have heard 6v lead acid batteries last longer than 12v. How do you think 6v would have done in these tests?
Well the flooded in these tests were 6V and they performed well. With the larger cells I think they would last longer as long as maintained. The maintenance is the biggest drawback to them as well as the offgassing. Be sure to do regular desulfation charges and keep them watered and check the Specific Gravity. If this is done they can last a long time. We used them in industry alot, but the maintenance on huge battery banks cost so much most of them were switched to gel or AGM.
Nice analysis, thanks..
You’re welcome!
I looked for prices. How much do they cost? MSRP.
https://battlebornbatteries.com/product-category/lifepo4-batteries/?afmc=1x
Thank you for running the test. This is the information I have been looking for while we make a decision to upgrade our battery bank. The information was very informative and helpful. The full blog and the video were very helpful. This is very timely information.
I fully agree that Wh is a much better measure of usability than Ah. I have found when discussing power management in our household and with others, watts of consumption is easier to identify and you do not need to think about is it 12V or 120V.
The need to change charging parameters for cold weather with lead acid batteries was new to me and makes using lead-acid more complex. I am pretty sure almost nobody is changing charging parameters for cold weather.
I am hoping that Battle Born will make the heated version of the Battle Born batter in the GC2 format. This would allow me to drop in replace the four GC2 6V lead acid batteries. I would want to see the performance and if the self heated GC2 could be an option for people wanting minimal impact in adding the battery to their RV.
We are likely going to move the batteries into one of the bays with a little insulation. We have the space just on the other side of the bay wall for where the current battery bank under the entry steps. This should make it easier for us to relocate the batteries.
I would love to use your testing as a reference in future content. I hope we can work out what makes sense to reference the test data. Your attention to detail is appreciated.
Thanks, Don. I sure learned alot through all this too! I agree the GC2 format would be great in a heated form. You could always use a heated pad and just add a little foam insulation too, thats what we did with the tesla in an unheated compartment and it worked well. 0F was the coldest we saw for a few days. (We try hard never to see those temps). Feel free to use the data and refference this, just provide a link back when possible or a citation. Good to hear from you!
Great read, I learned something. However I’m left with the following questions:
What’s the benefits of lithium if you’re plugged in to shore power 90% of the time?
If the lead acid batteries die and you’re plugged in to shore power will the 12v systems still work?
If going from lead to lithium is it plug and play or is it more complicated?
Without a solar setup what’s the point for lithium?
Would the results be the same if four 6v batteries were used instead of the four 12v?
Thanks for the great article.
Good. Question Mark, The Flooded we used were 6V batteries so that test was done. As for being plugged in most of the time, there is not much benefit to lithium other than lasting the life of the coach. Lithium is really best if you want to drain it regularly or with large loads. If the battery dies and your plugged in the 12V system will work because the converter will power the rig. Dont run the RV without a battery in the system however because it can cause voltage spikes. Most lithium with good BMS like the Battle Born will work as a plug and play, but will charge about the same speed as the lead acid. Replacing the converter / charger with one specific to Li will improve the charging speed.
Hi what software are you using to gather this data? I just built a bank yesterday of 18 everstart maxx-29dc and it would be interesting to run this same analysis.
We ran National instruments DAQ and logged the data through their software before exporting to excel. https://www.ni.com/en-us/shop/data-acquisition.html
While I believe your tests are accurate.
I had a 700-watt solar system installed with 4 AGM batteries producing 600 amps (300 usable amps) back in
2009 (before lithium batteries had come out) by AM Solar. Which produce matched systems for RVs. I used this system to boondock from 2009 to 2019. At times I had to turn on our Honda 3000i generator to top off the batteries in the evening because of less sun coverage or cloudy days. I only had to run the generator for a half hour to 45 mins to get back to full charge. I was running a 32-inch flat-screen tv, 24-inch flat screen tv, 1 Alienware desktop PC with a 750-watt power supply, and an Alienware laptop. I was also running a 110/12-volt freezer the whole time alongside the RV refrigerator. This system was run on our RV trips that lasted 3 to 5 months at a time over those years (10 years). That system back then cost us $7200. I looked into replacing that system with lithium batteries of about the same size. The battery alone was going to cost $3700. Not counting the wiring, solar charger, and other materials. So, you really have to way out how much boondocking you’re going to do, as to what kind of money you’re going to spend.
That’s a good point, the upfront cost should be considered as well as how much use is expected. Lifecycle cost will still come into play however as a lithium setup should basically be a lifetime battery for an RV or could even be moved. I would hope the cost comes down and they just come with the RV in the future and we don’t think about them any more.
Tom, you guys are great! I’ve been following you on U-tube for over a year now, and find your posts to be really helpful! Usually over my head, but I live that you don’t dummy down the content.
The summaries are all that’s needed!!
I am curious if you think that Battleborn batteries will preform differently from other lithium-ion batteries? I wasn’t able to get the Battleborn batteries when I upgraded, but the RV service center ( that’s highly regarded, and I feel dependable) sold me what they considered an equivalent brand. I understand that your sponsorship might prevent you from testing alternative lithium batteries, but If ever possible your opinion will reassure me!
Again ,thank you to you and Caitlin. I registered for a Alaska Fantasy travel trip for next spring ( if the borders open) based on your “Going North” series!
Glad you enjoy the content and I hope you can make it to Alaksa! You will love it. As for testing different battery types, I do hope to do that in the future. As a whole lithium should perform pretty similar to these test across the board. The biggest differences between batteries really comes down to the BMS that runs them and sometimes the cell type. In general cylindrical cells are known to have longer cycle life than prismatic or pouch cells. The BMS is the biggest weakpoint and I hope to tourture test them in the future. Just looking at the different BMS units i do think Battleborns is superior to most of the China batteries I have seen. It is a custom in house designed unit with oversized FETs and filtering to protect them in shorts and transients. In some cases just time will tell for longevity.
Where did you get your cycle life estimates from for AGM and Flooded? They are wildly disparate and I know that Trojan projects flooded to have MORE cycles in flooded than AGMs of similar construction…. if maintained properly. If actual cycle life (as defined) is significantly different than what you used,,, lifetime energy costs would be quite different,
Why did you not publish the names of the brands you tested against BB? Were they top of the line or run of the mill or Chinese?
If you camp 100 days a year and cycle to 50%… it takes 10 years for 1000 cycles. So I think lifetime battery energy production is certainly valid especially on a per dollar basis… but a more realistic measure would not be reflecting costs beyond my projected life expectancy! LOL
For the record…I think Lithium is great for a number of reasons AND can pay for its’ initial costs in a reasonable time IF you are living Full Time AND boondocking in an RV. For most of us it will not pay off economically at this point because we don’t do that and we’ll never see those 3000 , 5000 or 7000 cycles before we sell or die, BUT just like our RV;s …Lithium may be a bit more expensive but worth it for all the other benefits …like quick charging.
I agree with you on AGM’s… though they too have their place for those who hate maintenance and love the low self discharge rate as they store their units, The myth that they provide more cycles or power …you’ve effectively demolished.
Thanks for a well done piece and all the work
Glad you liked it. Lifecycles were from the manufacturers spec charts for the batteries. As for the brands, AGM 1 and 2 are top of the line US manufacturers, AGM3 and Flooded are cheaper brands. I did not disclose brands because I am not trying to slam any particular brand or bring any lawsuits. I decided to do this just before publishing after what we discovered. You have a great point about the cost per what it will be used for and I think that needs to be decided on a case by case basis, but at least you now have the data and can make a more educated descision.
Clearly, the battle line is drawn between a US company that packages LFP cells and the Chinese who manufacture pouch or prismatic cells. The latest guy to test Chinese cells is Off Grid Garage, who found some 280 AH shrink wrap type cells, and they run around $500 for a set. That is mid 100’s per kWh, which is very cheap. His source is a fairly small company, but they seem to manufacture the cells with a high degree of automation. Their brand may be EVE and the company is Shezhen Basen. Easy to find on Alibaba. A step up MeritSun, with maybe 100 employees and a very impressive manufacturing plant, as featured on YouTube. It’s a nice virtual tour.
Rather than saying the prismatic cells from China are unknown (they are certainly tested), it’s fair to ask why no American company is building a factory to compete with these Chinese companies. Most manufacturing is for EV’s but the smaller Chinese companies seem to be aimed at global consumers. Their shipping can be reasonable. A set of prismatics with a good BMS is a decent pack. There are ways to monitor temperatures, and it’s kind of trivial to heat the batteries in an insulated kind of situation.
Does Battle Born think it is enough to NOT have a manufacturing faciility for the cells.? I don’t know where they get their cells, or if they are branded. So many US companies just want to grab Chinese parts and do branding and marketing. Yikes, why can’t the Chinese sell their products directly? This seems to be what is happening, maybe with SOK right now, certainy on Alibaba. I don’t have enough information to say how the cells versus pouches works out. I have an ebike pouch pack that is 6 years old with very little capacity loss. I own some CALB cells which must be prismatic, but I’m not sure. I own a pack with Sony branded cells that was cheap, used.
I don’t know why you don’t buy some prismatics, especially as the price seems to be dropping rather quickly. If I bought the 16 cell (48v) package that Off Grid bought, I could run a heatpump and pretty much have an all electric RV for a rather low amount of money. I’m not sure what is happening in China, with companies like Basen and MeritSun. There was a recent report that the EV (bus) cost per kWh is sub $100, basically Chinese.
Full River is a Chinese company and they sell in the US under their own name. They also sell other company branded batteries.
https://www.fullriverbattery.com/
Trojan makes a watering kit, so easy. When my ship comes in , I will get four 100 amp Lithiums. Until then my 4 large floor machine 6v batteries will do, I use solar and a real quiet generator solves many power issues and money issues .I spent $1300 on these batteries, it would have been over $4,000 in lithium. Bottom line do you use them or just want them.
We use Battle Born’s Lithium Batteries in our RV and have been very happy with their performance. 🙂
Love the detailed analysis. It’s so great to have this research. One question: your charts show that the cost of a BB is $900 (which seems correct), but then in your calculations of the cost per energy, you show that the two BB cost $1,600. That seems incorrect? Even at $1,800 the BB still come out on top, but not by as much.
Hello, I appreciate the data and your time spent in analysis. Watched the video twice, lots of information! It does somewhat come off like a battle born commercial but other then that I believe what is provided to be accurate and well done.
AGM batteries are truthfully the worst in my opinion and having spent 20 years in an industry highly reliant on batteries for power storage, I have tried many various AGM style batteries in order to get away from the maintenance issues of flooded batteries and have been hard pressed to find a cost-effective one yet. I find them to be very temperature and environmentally sensitive with extremes on both sides greatly affecting their performance and longevity.
I do however wish you had selected a quality flooded lead-acid battery for your comparison like a Trojan T-105 or US 2200. I believe your results would not have been as favorable towards the cost-effectiveness of the Lithium option. I would however been interested in the results as all my experience is based on tests with much less of a controlled environment and were always focused on hours of performance / rated capacity and longevity of the battery in real life use.
In my experience there is a very large difference in both “real” rated capacity and longevity in the lead-acid battery market. I feel this is mostly due to the quality of the source material (specifically the lead) used in the manufacturing of the batteries. While purchase price would play a factor in the overall operating cost, your $90 POS lead-acid would only be around $150 per battery on the quality side of the market and the performance both in capacity and life in my experience would be close to three times the overall result. In some of my longevity tests in real life we were lucky to get two years out of a cheap flooded lead-acid while either one of the quality batteries mentioned would have over a 5 year life span with similar use. Run time at a 60A to 70A draw we found to also be at least 50 to 60% better, somewhat related to better rated capacity on the $150 battery however but also as you have exemplified, the $90 battery would not even meet its stated capacity especially after numerous cycles. This of course would all rely on proper maintenance which can be somewhat a bother but just needs to be added to the list with all the other routine items on any RV.
All that said, Battle Born seems like finally a decent option for a maintenance free battery albeit at a very large upfront cost. Happy Trails!
Thank you, Kerry. We use Battle Born batteries in our RV and have been very happy with their performance. Yes, they are expensive upfront, but we still believe they are more cost effective in the long run. Happy Trails to you as well!
We have lived aboard in the Med for the last 15 years and our Lifeline AGMs lasted 14 years. Lithium might seem to be the ‘Magic’ battery – but at a huge cost of both the product and the installation and monitoring kit. If you don’t fully understand batteries and charging and replace your batteries when the lights go dim then Lithium is not for you. They are not simply a plug-in replacement.
I am currently running 2 12v Group 24 lead acid batteries in my TT. If I were to go to Lithium Ion, would a new controller be required and if so, what price range would it fall in?
I have got an article coming out about this soon. As long as your current charger does not have automatic equalization or it can be turned off you can use it. A lithium dedicated charger will charge the batteries faster however. A lithium dedicated charger will run about $200.
Great results with all the time and effort you and Battle Born put into this research! I’m sold in lithium batteries and Battle Born Company. Fantastic job, well done!
Thank you, Phil
Thank you, Phil. We’re sold on lithium, too! 😉
Have a question. Would you use a lithium ion battery in a motorcycle?
If you’re referring to it as a starting battery, probably not. You could still have heat and current issues. If you wanted to put a small external power source onboard for an adventure bike then yes a small lithium battery is a great option, note that with lithium they can draw a lot more power so a small DC-DC converter for charging would still be ideal.
This is very useful information. I must say I am surprised at the data you gathered. Really good job putting this together, I learned a ton. I thought watt hours and amp hours were the same. Thanks again
Thank you! Glad it was useful. 🙂
Thanks, great article with lots of “real data”. I’ve passed the link on to several others.
Thank you for sharing the article with others!
The test information is a great way to compare power sources. However I had issues with testing with Battle Born only. I use different batteries, Lion Energy UT1300, which have given me similar results but come in at a lower cost.
Battle Born does have a good product, but like Apple, also has great advertising and a giant megaphone from those who have been supplied with their batteries.
Just my opinion.
Yes most lithium should perform similarly. I would love to do some head to head testing of Li Ion in the future. The biggest differences are in the BMS and cell type (prismatic, cylindrical or pouch). I could write an entire article on these things and hope to do some testing in the future.
Congrats for this gorgeous technical blog on batteries. On the other side if we want to move on Li we have to consider replacing the power converter on our fifthwheel. So this cost has to be considered when moving from lead acid to Lithium. For the moment we have only one 12v and we look to upgrade with two batteries in parallel (12v) or series (6v) just to have enough autonomy for a week-end with the furnace, water pump and some lights.
Thanks again
Thank you for reading!
Really liked your video about cold weather charging the lithium batteries. You r a smart guy! Don’t have money for lithium but it’s good having some knowledge about them!
I was told at a van build the wire size from the solar panel makes a difference in charging.
Do you have a recommendation?
Thank u
Yes having the appropriate wire size is very important. It’s going to depend heavily on how much solar is installed and what voltage they are running at because you want to avoid a voltage drop. Using an MPPT charge controller will help this a bit. Theres a lot that goes into the decision and I plan to write an article on this eventually.
Kudos to you for producing this great educational video and associated blog. I’d like to keep it on my laptop for future reference. In that regard, I was wondering it I could Share the blog to myself via email. I see you have the options of sharing to Facebook/Twitter/Pinterest, but the Share Icon is not active for anything else. Thanks.
Thanks for your comment. I just enabled the email share at your suggestion. It will just copy the link however into your email client. If it does not work you may need to manually copy the link or text.
My agm start batteries need replacing but my 4 6v agm house batteries are fine. Since your recommendation is lead acid is ok for start batteries can I mix the 4 agm house batteries with 2 lead acid for start batteries and not have any problems. I have A 2005 cat 400 hp diesel engine which requires total start battery size at 1500ah. We live in the Dallas area and usually head for warmer weather in Jan-Feb. Most likely will only keep MH for another year.
Hey Gary, I thought I had replied to this, but maybe not. Its usually not a good idea to mix battery types, especially if some are older than others. This can cause an unbalance that will damage the new ones prematurely. Usually the House and start batteries are not connected however, so using two different types is ok. Some RVs have a “parallel” button usually on the dash to connect them together for a short period of time to start. This is ok to do, you just don’t want to leave them connected. As far as battery size 1500 Ah is a huge amount of battery, you may be meaning CCA or cold cranking amps. That is the starting rating and yes flooded batteries can provide this very well. Just remember to check the battery water levels every few months to make them last as long as possible.
While the data is no doubt good, the conclusion, as others have implied, disregards Time Preference (https://en.wikipedia.org/wiki/Time_preference). It would make more sense for many weekenders or users who use hookups to simply buy the lead acids and replace them periodically.
THANK YOU for an excellent review! Hope you might one day add some of the new storage batteries coming out.
You’re welcome! 🙂
G’day!
Just watched your entire video and I’m curious why you used 12.2 Volts as the cut off for the AGM 50% depth of discharge when it clearly says in the manual (you show it at about 2:10) that 12.2V is open circuit voltage and the battery must be rested with no loads for 4 hours before an accurate reading can be taken.
By stopping the test at 12.2v (or 11.8V in your case) and then letting the battery rest for >4 hours you would’ve likely ended up with a battery at around 12.5V suggesting a DOD of around 25% (not 50%)
An under load voltage of around 12V at 50% capacity checks out pretty well. If you stopped the test there I’d imagine if you let the battery rest it would end up with an ICV of ~12.2V
Doesn’t this invalidate a lot of your comparison. To be fair I didn’t open your spreadsheet on my phone so maybe I missed something… but I’m still curious whether there is an explanation?
That’s a fair question and part of the reason we did some deeper discharge testing down to 11.8. I talk about recovery a bit as well. Setting your cutoff is tricky with lead-acid in general because under very light loads recovery is minimal, thus under a slight draw the battery will shutdown near 50%. However under a heavy load, yes it will shut down way to early. Setting your cutoff based upon your expected load is going to be important for lead-acid.
It seems to don’t understand Cahn Turner’s question – which is exactly the same question that I posted on your YouTube channel. Lithium don’t have this problem – they maintain the voltage quite well under load, but all lead acid batteries must be allowed to ‘rest’ before you measure the voltage and draw the conclusions you came to. This is battery basics 101.
This is true to some extent and was mentioned, however, most people never rest their batteries and will not benefit from the voltage recovery of a 20-hour period.
A problem with the life cycle cost is the assumed cycles.
Assuming 1 cycle per day of use.
10yrs full time would be 3650 cycles not 12000.
If you only use the rv 60 days per year that’s 600 cycles.
Most people will junk the rv long before they get the 12000cycles…so it’s under calculating the cost for lithium.
I’ve owned RVs (and lived on a sailboat!) off and on for two decades, and I’ve always ended up shrugging my shoulders and hoping for the best when it came to house power. Now that we have a newer fifth wheel, I’m trying to decide what direction to take house power and charging. The typical forums are filled with opinions and tribal knowledge, but little data. Your testing methodology and explanations were tremendously helpful, and provided useful real-world comparisons. I’m mechanically inclined, but certainly no electrical engineer. I still came away with a much more thorough understanding of the state of the art (or science) in power storage today!
That’s great! We’re so glad you found our data helpful.
I used this Optima 8016-103 D34M BlueTop Starting & Deep Cycle Marine Battery for about 4.5 years and it still works perfectly. My RV stays parked much of the time, but I don’t have to worry about the battery when I take it out. This product has a distinctive SpiralCell design together with continuous lead plates, which is capable of supplying a safe, strong and clean source of power. I am impressed with this battery because it actually serves a dual purpose: as a starting and deep cycle battery. Besides that, this battery has good vibration resistance, it is even fifteen times more resistant to various forms of vibration compared to other marine batteries.
With regards to vibration resistance, this one tops the list. Vibration from trolling motors and moving RVs and other vehicles can damage a battery, but this one is 15 times more resistant to vibration than other marine batteries.
I’ve used sealed lead-acid batteries in the past (and UPG batteries before that), but I heard from a friend that while sealed batteries are a good choice, I should consider a longer-lasting battery to avoid the need to worry about finding a replacement every few years. So I decided to go with a lithium battery for my RV. I trusted and opted for the deep cycle battery from Battle Born. It weighs just 29 pounds, a lot lighter than the 63-pound UPG batteries I’ve had, and the extra weight of the UPG batteries is just a load. That’s why, despite the fact that these AGM batteries are perfectly adequate for my system, I adore them.