RV batteries are the powerhouse of your RV. If you plan to camp off-grid, boondock, or just stay overnight without electrical hookups you’ll be relying on your battery(s) to run your refrigerator, lights, and CO2 sensor, among other important items.
Unfortunately, most house batteries that come stock on your RV aren’t sufficient especially if you like to camp off-grid frequently. That means you’ll probably want to upgrade your batteries to better suit your needs. To help you determine the best RV battery we compare the three main types of RV batteries sharing the pros and cons of each and explain why we ultimately decided to go with Lithium batteries for our RV battery bank.
RV battery basics
Before we dive into comparing the three main types of RV batteries — let’s cover the basics. Batteries come in all different voltages, but for RV house batteries the most common types are 6-Volt or 12-Volt. You can buy a 12-volt battery, or connect two 6-Volt batteries to create a 12-Volt battery, but ultimately your RV will be powered off of 12-Volts.
The job of an RV battery bank is to power items on your RV that run on D/C power like your lights, water pump, refrigerator (when it’s on propane setting), C02 sensor, slides, or other basic items on your RV. It will not power anything that runs on A/C power like your electrical outlets, TV, or fireplace. If you want to create A/C power from your D/C power from your battery bank, you’ll need an inverter.
Batteries have an amp-hour rating that varies by the type and size of battery you purchase. Amps refers to the amount of electrical current a device draws, or in other words how much electrical current an appliance draws from the batteries to run. The Amp-hours (Ah) tells you how many hours you can run your appliances from your batteries. The higher the Amp-hours, the more energy you can use for a longer period of time before the battery needs to be recharged.
The last important thing to know about batteries is that each battery type has a specific Depth of Discharge (DOD) limit. If a battery has a 50% DOD limit, you cannot use more than 50% of the battery’s amp hours without damaging the battery. Essentially, your battery bank’s usable energy is cut in half. A 100Ah battery with a 50% DOD would really be 50 usable Ah.
Types of RV batteries
There are three main types of RV batteries:
Lead acid batteries are the most common type of RV battery and are likely the stock battery you received from the RV dealership or manufacturer when you bought your RV. They are the cheapest most widely available option but require the most ongoing maintenance.
Lead acid batteries have electrolyte levels that require adding water to the batteries as needed. They also have a tendency for the terminals to corrode over time. Beyond the ongoing maintenance, they also have the least efficient charge and discharge rates out of the three most common types.
In comparison to other battery types, they charge and discharge at a less efficient and slower rate, meaning it takes longer for your batteries to recharge, and may struggle to keep up with high-draw appliances like a microwave. They also require proper ventilation. As they charge and discharge, they emit toxic gases. If not vented properly they can overheat and possibly catch fire.
Additionally, lead acid batteries should not be drained below 50% of charge (DOD) and are heavy weighing around 50-60 lbs for one battery.
Pros of lead acid
- Low cost ($25 – $50)
- Readily available (anywhere that sells batteries will have these including Walmart)
Cons of lead acid
- Ongoing maintenance like checking water levels and adding water as needed
- Heavy weighing 50 lbs. per battery
- Requires venting giving off toxic gases
- Less efficient charge and discharge rate
- 50% DOD limit, meaning your 100 amp hour battery is really 50 usable amp hours
- # of cycles: 300-500 (at a 50% DOD) that’s around 2 – 3 years.
AGM deep cycle
The next step up from a lead acid battery in both cost and efficiency is an AGM battery. AGM stands for absorbent glass mat. These are lead-acid deep-cycle battery that has a mat sealed inside the battery that absorbs the electrolytes. This means you no longer have to monitor the battery’s electrolyte levels yourself or add water to the batteries.
AGM batteries charge and discharge at a more efficient rate than a standard nonsealed lead acid battery, but still have a 50% DOD limit meaning a 100 amp hour battery really has 50 usable amp hours. An added bonus of AGM batteries is that they do not require venting and don’t expel hazardous gases as you see with a lead-acid battery. They are heavy, weighing around 70 lbs. per battery.
Pros of AGM
- Low cost ($150 – $300)
- Still available in most stores that sell batteries, but not as widely available as a lead acid battery
- More efficient charge and discharge rates than lead acid
- No toxic gases, meaning no venting is required
- No ongoing maintenance
Cons of AGM
- Heavy weighing 70 lbs. per battery
- 50% DOD limit meaning your 100 amp hour battery is really 50 usable amp hours
- # of cycles: 800 – 1,000 (at a 50% DOD) that’s around 4 – 7 years.
Lithium iron batteries (LiFePO4) are the newest form of technology for RV batteries. Simply put, they are the best RV battery out there. Unfortunately, they are also really expensive.
They are extremely efficient for both charge and discharge and are able to handle a much larger or faster draw from the batteries than AGM or lead acid. Most lithium batteries have a built-in battery protection system (BPS) to stop them from overcharging or over-discharging.
Technically they have a 100% DOD meaning they can be fully discharged without causing damage. Although most manufacturers suggest staying in the 80% – 90% DOD to extend the life of the battery. This means a 100A battery is around 80-90 usable amp-hours but could be 100 usable amp-hours if needed.
Additionally, lithium batteries have a long life cycle. They last around 3,000 – 7,000 charge cycles which is three times the charge cycles as AGM. Or 10 times more charge cycles as lead acid batteries. While it’s more money upfront. Over time you are buying fewer batteries, creating less waste, and saving money.
Pros of lithium iron
- Light weighing 30 lbs. per battery
- Most efficient charge and discharge rates
- No toxic gases, meaning no venting is required
- No ongoing maintenance
- # of cycles: 3,000 – 7,000 (depending on DOD used) that’s 8-10+ years
- 100% DOD, although an 80% – 90% DOD limit is advised.
Cons of lithium iron
- Expensive: $750 – $2,000+ (depending on the # of batteries you buy)
- Not widely available in stores. Mostly bought online.
- Don’t perform well in extreme temperatures.
At this point, you may be wondering, “how do I monitor my lead acid or AGM batteries to make sure they don’t drop below the 50% threshold?” Most RVs, trailers, or fifth wheels, have a “button” that allows you to check your battery levels. This button is supposed to show you the level of charge your batteries are at. However, it’s not always accurate.
To accurately monitor your batteries you need a battery monitoring kit (BMK). If you don’t have a BMK you can use the button to estimate your levels. With our AGM batteries, we tried not to let our batteries go below 50% of the total charge. We consider the 50% mark, “empty” which is around 12.0 volts.
We consider fully charged 13.0 volts. Technically, you can drain your batteries lower than 12.0 volts, but doing so will be detrimental to the health of the battery.
This is a generic chart and may not accurately reflect your exact setup, batteries, or rig. If you are concerned with the numbers a BMK might be a good solution for you.
The right batteries for you
When we had our fifth wheel, we purchased deep-cycle AGM batteries. This was mostly because it was what we could afford at the time. But it was also due to space and weight constraints. Since our new Class C RV has a much lower cargo-carrying capacity and far less space, we needed to choose a battery that gave us the largest amount of amp hours with the least amount of weight and space. For this reason, we decided to go with Lithium Iron batteries.
Our battery bank is 300 amp hours (three 12V 100A lithium iron batteries). It was an expensive upfront investment, that could cost you anywhere from $1,500 – $2,000 depending on the company you went with. The best way to justify the upfront cost of our batteries is to do a side-by-side comparison of a 200 amp battery bank in both AGM and Lithium batteries.
*If you have a lead acid and are happy with it, please feel free to replace it with another lead acid. However, considering the extensive disadvantages lead acid batteries have, we feel they shouldn’t even be considered as an option for upgrading. Not to mention, the highest amp hour rating we could find at Walmart for a lead acid battery was a 12V 24Ah battery which means you would need 4 batteries to reach 100Ah.
Where to buy lithium batteries
We recommend Renogy’s lithium-iron batteries. However, there are a ton of other brands to choose from. A popular brand amongst RVers is Battle Born. AIMS Power and ReLion also sell lithium batteries too. Most batteries use the same technology, so you’re really investing in the company. Look at their warranty and make sure they are a company that will last. After all, a 10-year warranty is only good if the company is around in 10 years.
If you can’t afford Lithium batteries at this time, consider saving up for them. In the long run, they really are the better choice. Ultimately, the best RV battery is the one that fits your needs and budget.