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

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

Batteries can be one of the more confounding pieces of equipment when it comes to motorhomes. There’s one battery under the hood (a starting battery) and another somewhere in a bay or cabinet (a house battery). So, what’s the difference between RV house batteries and starting batteries?

Though these batteries usually look similar, they serve very different purposes. If you understand the fundamental difference between house and starting batteries, you can easily choose the best option for your camping style and budget. Here’s a quick breakdown for you.  

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 could 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 that 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 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.

Are Starting and House Batteries Different?

Yes, starting batteries and house batteries are different, and you should not combine or interchange them except for emergencies.

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.

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.

What Are the Best House Batteries?

Without a doubt, deep-cycle lead-acid or lithium-ion batteries are the most common options for RV house batteries.

Deep cycle lead-acid batteries provide consistent energy over long periods to power the electronics in your RV. Ideally, they should also be a sealed battery. Sealed batteries are maintenance-free and will improve your experience using them.

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Deep-cycle lithium-ion batteries are typically an upgrade on most RVs but are the best house battery option. They provide tremendous benefits over their lead-acid counterparts.

Lithium-ion batteries supply more power, and you can run them nearly to zero without damaging them. They’re also lighter than traditional lead-acid batteries and completely sealed and can be operated in any direction.

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!

How Long Do RV Batteries Last?

How long an RV battery lasts comes down to how well you maintain it. Lead-acid batteries are more fickle than lithium-ion batteries. 

This is our set of house batteries, we use battle born lithium ion

Lead-acid batteries typically last anywhere from two to five 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 10 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.” 

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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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.

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