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RV House Batteries vs. Starting Batteries: What’s the Difference?

RV’s all have batteries. Like your phone, they need to keep operating their electrical systems when mobile. Motorhomes and drivable RV’s even have two sets of batteries, the house and starting (or chassis) set. So, what’s the difference between these RV battery types?

Though these batteries usually look similar, they serve very different purposes. Understanding the fundamentals of these systems will help you select the proper type for the application and use them correctly.

What Does an RV House Battery Power?

An RV house battery powers everything that operates off of a 12V current. This includes the cabin lights, fans, water pumps, the control panels for appliances like the refrigerator and furnace, and sometimes a television.

Most standard RV house batteries will not power 120V appliances because they would quickly use up the limited power that a 12V battery can supply. You can upgrade the house battery to a battery bank with enough energy to run 120V appliances via an inverter, but it can be costly.

Many people who choose to have a large battery bank opt for solar panels to help keep them charged. You also charge a battery bank when plugged into shore power.

What Does the RV Starting Battery Power?

An RV starting battery (also known as a chassis battery) provides power to start your motorhome’s engine. It also powers the usual things in your motorhome that a car or truck battery would, such as windshield wipers, lights, and the radio and headlights.

RV battery house vs. starting infographic

Can the House and Starting Systems Be Combined? 

You can combine an RV house battery and a starting battery, but you should only do so in an emergency. If the starting battery dies, you can connect the batteries and potentially provide enough power to start your vehicle.

Most motorhomes and large boats with house batteries will have a button or switch that allows temporarily combining the battery banks for starting an engine.

The house battery and starting battery are used for very different functions, so combining them long-term is not wise. It can lead to accelerated wear and tear, shortening the lives of both batteries and could leave you unable to start your engine. One of the major reasons the systems are separate is to give redundancy for starting your engine even if you accidentally draw down your house batteries (much more likely)

battery boost combiner switch
Many RV’s and boats will have a button that temporarily combines the house and starting systems. The battery boost button on our motorhome does just this and can help start the engine.

What is the difference between a starting battery and a house battery?

Yes, starting batteries and house batteries are different, and you should not use the same type for both systems.

A starting battery needs to provide cranking power to start your motorhome’s engine. It provides short, powerful bursts that start the engine. This battery type is not meant for large energy usage besides starting and quickly gets recharged by the engine.

A house battery is a deep cycle battery, which means it can provide consistent power over a longer period and can be drained much deeper. This is the perfect type of battery to power the 12V appliances in an RV.

The difference in the batteries is in their construction and chemistry. Starting batteries use a lead acid chemistry and design that can provide enormous amounts of current for very short bursts. Lithium-ion house batteries don’t provide high currents but have very long runtime and far more energy overall.

What Are the Best Starting Batteries?

The best starting batteries are AGM (absorbent glass mat) or VRLA (valve-regulated lead-acid or sealed lead-acid) batteries. These types of batteries are sealed, maintenance-free, and leak-free. They also provide the cranking amps needed to start an engine and offer a relatively long service life when used primarily for starting.

What Are the Best House Batteries?

Without a doubt, lithium-ion batteries are the best choice for house batteries in RV’s. However deep cycle lead acid have been the norm for many years until now.

Deep cycle batteries are designed to provide consistent energy over long periods to power the electronics in your RV. While deep-cycle lead acid does this to some extent, discharges below 50% of their capacity quickly lower their lifespan.

Deep-cycle lithium-ion provides tremendous benefits over their lead-acid counterparts. They supply more power, and you can run them nearly to zero without damaging them. They’re also far lighter than traditional lead-acid batteries and completely sealed and can be operated in any position.

Lithium-ion batteries are more expensive than lead-acid batteries, but most RVers who use them find the value balances out the cost.  We personally use a set of Battle Born lithium-ion batteries to power our RV and office. In fact, our house batteries are powering the computer I type this on now!

Don't Waste Your Money On Batteries - The Shocking Truth I Discovered When Testing RV Batteries

How Long Do RV Batteries Last?

RV chassis batteries can last 5-7 years if they are kept charged and not left to die. Every time a starting battery dies in a vehicle it takes 50% or more off its life. Thats why once you have a dead battery once, it will happen far more frequently until you replace it.

How long an RV house battery lasts comes down to how well you maintain it. Lead-acid batteries are far more fickle than lithium-ion batteries. Lead-acid batteries typically last anywhere from one to three years. If you run a lead-acid battery below 50 percent of its capacity, it will sustain lasting damage. The more frequently you drain the battery below the 50-percent threshold, the shorter its lifespan will be.

Lithium-ion batteries can last upwards of 15 years or more. A lithium-ion battery does not have the same 50 percent damage threshold as a lead-acid battery. You could deplete it to 100 percent of its capacity, though most battery management systems stop lithium-ion battery depletion at about 80 percent, and the battery will register as “dead.” 

Pro Tip: If your wondering how long battery runtime will last read our article all about it!

Tom replacing RV battery
This set only lasted us 2 years! We replaced with lithium, which should last 10-20!

Which Battery Meets Your Needs?

There’s a distinct difference between RV house batteries and RV starting batteries. It all boils down to house batteries needing to provide a consistent amount of energy over a long time, while starting batteries need to deliver a quick burst of cranking amps to start an engine.

There are undoubtedly different options within each of these categories, but now that you understand the basics, it should be much easier to find specific batteries that meet your needs.

Happy camping!


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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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Ted Guthrie

Friday 13th of October 2023

Why are you recommending 800 watt solar panels for basic battery maintenance and on board lighting in an 18 ft. travel trailer with led lighting? That is overkill, is it not??

Jeanne

Sunday 8th of January 2023

Hi Tom and Caitlin,

I recently bought a 1996 Dodge Campervan. The previous owner had installed a battery disconnect for the starting battery. He advised me to disconnect it when I'm not using the van (though I don't understand exactly for how long "not using it" means). I have been doing that. What about the deep-cell house battery? Should I also disconnect it under some circumstances? There is a 50w solar panel on the roof.

Thanks for your help, Jeanne

Mortons on the Move

Monday 23rd of January 2023

The previous owner probably noticed the van had a draw that would kill the starter, how quickly that happens will be specific to your van but I would hope you only would have to do that when storing for maybe a few weeks or longer. As for the house deep cell, its good to disconnect that too in certain circumstances that might drain it. As long as everything is off that 50 watt solar should keep it topped off if its outside. If your storing inside and not plugged in then disconnecting the deep cycle batteries would be best as small parasitic loads will drain it. Basically, RV's alwasy have a little battery drain and it needs to be made up for by shore or solar, or disconnected.

RVNOLAfolks

Friday 2nd of July 2021

Interesting article on batteries. Do you think crank batteries will eventually be replaced by a type of Li battery or will it likely be some other chemistry?

Mortons on the Move

Thursday 3rd of March 2022

I bet that when solid-state Li batteries become available we will see cranking options. They will have higher current and temp limits. Technically the current Li can do it but its hard on the BMS systems.

Loneoutdoorsman

Sunday 27th of June 2021

Hi Tom and Caitlin. Loneoutdoorsman here. Ey purchased two Battle Born Batteries 6 months ago. They are a perfect combination to the 400w of solar setup from A & M Solar Company located in Springfield Oregon. Would you please comment on the use of Lithium ion batteries to start the 2500w propane generator. Thank you for providing very factual RV information. Burn Diesel Arctic Fox 990 Truck Camper on a Ford F-350, diesel, 4X, duel.

Mortons on the Move

Thursday 3rd of March 2022

Your continuous current limit is 200A but it can burst to 400 for a short bit. Starting big motors is a problem with these limits but a 2500 watt generator should be fine with that setup. The batteries will just shut down if they are overloaded.