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What are ‘House Batteries’ in an RV? (FAQs)

What are ‘House Batteries’ in an RV? (FAQs)

When it comes to the world of RV ownership, there are a lot of technical terms and new systems you’ll need to learn. One of the most important systems is your electrical and battery setup. Have you ever heard the term ‘house batteries’ and been a bit confused? You are not the only one.

So, what exactly are House Batteries in an RV?

House batteries in an RV are batteries that provide power to all of your electric devices in the RV when it is not connected to shore power in a campground or powered by an optional generator or solar panel array.

This is just a small portion of what you should know. You also need to be aware that there are several types of house batteries, but also some more facts we will explain in this article.

House Batteries in an RV Defined

As I’ve said above, they are the batteries that power all of your electrical devices in the RV in the absence of other power sources. Those other sources can be:

  • shore power
  • power generator
  • solar panels

House batteries are most commonly 12V DC type, though on some RVs they can be 24V DC, as their electrical systems are designed for this voltage. They are rechargeable lead-acid batteries, very similar in design to the car or automotive batteries, but there are some very important differences between these two.

Difference Between House and Automotive Batteries

The most common types of house batteries are built with the same technology as the car batteries, the lead-acid type. But there are some substantial differences, which means that you can’t replace a dead house battery with any car battery.

House batteries are the so-called deep-cycle type, which means that they can be discharged slowly and below 80% capacity without any additional wear, beyond the normal expected wear from normal use.

While car batteries are designed to produce very high currents over short time intervals, no longer than 30 seconds. Because of this, car batteries have lead plates that are almost paper thin, more of sheets than plates. House batteries have much thicker, lead plates.

Types of RV House Batteries

While RV house batteries are very similar to car batteries, there are still several types of them, which at the first glance are completely unrecognizable as lead-acid batteries. Especially for the inexperienced eye. These types are:

  • flooded lead-acid batteries
  • gel lead-acid batteries
  • absorbents gel mat batteries
  • lithium batteries

All of these types have certain advantages and disadvantages over the others, which we will go into more detail next.

Flooded lead-acid batteries

Flooded lead-acid batteries are the most similar to car batteries, and the oldest type of specialized RV house type. They are made of thick lead plates immersed in sulfuric acid.

This type is the most common and most affordable one. But they require occasional checks of the acid level and adding distilled water. The thicker plates make them suitable for deep cycling, and most of their life you will get if not recharging them before they reach 50% of their capacity.

Gel lead-acid batteries

This type is practically the same as the flooded type but has silica added to the acid solution because of which it is thicker and gel-like. Hence the name – gel lead-acid battery. This gel makes them more resistant to deep discharges, beyond 50%, and also able to withstand a higher number of discharge-recharge cycles.

But, they are also very sensitive to overcharging, so you shouldn’t use them on RVs that do not have a smart charging converter that will protect them from this.

Absorbant gel mat (AGM) batteries

When you open an AGM battery it looks nothing like its ancestor, the car battery. Between lead plates you will not find the liquid acid solution, instead, there are absorbent mats that are soaked in acid.

Because these silicon mats are not cheap, these batteries are the least affordable. But, they are also the longest-lasting lead-acid type, both in capacity and lifespan. So, in the long run, they are the most affordable type.

Lithium batteries

Lithium batteries are the latest technology for RV house batteries. They are the most expensive and the least common type. They are also with the highest capacity and longest lifespan.

Most common are the LiFePO4, or lithium ferrite phosphor batteries. These are practically the same batteries you can find in any laptop. But much bigger in all dimensions.


What is an RV inverter?

RV inverters are electrical devices that convert the 12VDC of your RV house battery into 120VAC power used by your appliances. Inverters also have bypasses that allow for your 12VDC lights in the RV to be powered directly from the house battery.

On most of the newer RVs, the inverter is built into the transfer switch together with a converter, so you can easily switch which power you are using, house batteries, shore power, or optional power generator, if your RV is equipped with it.

What is an RV converter?

RV converters are in essence the opposite of the inverters, they convert shore powers or generator’s alternate current into the direct current. While many people will tell you, and it is written in many articles, that they convert 120VAC to 12VDC, this is not true. You must understand why it isn’t so.

Electrical power always flows from the point of larger potential to the point of lower one, and an electrical potential is just a fancy name for voltage. So, to charge a battery you must supply it with a higher voltage than its 100% charge voltage. This means that converters must provide a higher voltage than 12.4VDC.

And they do, they provide between 14.4VDC and 17VDC, so if your converter doesn’t have smart charging capability, you could overcharge your house batteries.

What does amp-hours rating mean?

The capacity of house batteries is expressed in amp-hours, and it is a calculated value based on the battery’s ability to produce a certain constant amps amount over 20 hours period. For example, a 100Ah battery will produce 5A over 20 hours. This is the only certain running time. If the battery produces a different level of current, you can’t simply recalculate it.

Because of its chemistry battery has shorter running times with higher and longer running times with lower currents than the 20 hours baseline. For example a 100Ah battery, if a constant draw is 4A, it will not last 25 hours, but closer to 28. At 6A will run for 12-13, not 16.5 hours.


Closing Thoughts

Knowing what various devices of your RV allows you to make full use of them, but also repair or replace them when and if needed. One such thing to know is what are house batteries in an RV.

They are the source of power for all your appliance in the RV when it is not connected to shore power or some other source like a generator or solar panels.


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