RV Battery Options What You Need To Know

There are so many options for batteries in our RVs and each comes with their Pros and Cons. We rely on RV batteries for so many things like awnings, leveling jacks, slides to operate, lights, water pump, and even the fridge. 

The most popular of battery choices starting with the most basic to high end is:

1. 12Volt Deep Cycle Battery

2. 6 Volt Golf Cart Battery

3. Maintenance free AGM

4. Lithium LiFe PO4 Batteries

     RV Battery Properties

     When looking at batteries there are a few things to keep in mind to help us compare them.  First one we will look at is Capacity. Most manufacturers use a 20 hour rate for determining how many amp hours are in a battery.  For example, if a battery is rated at 100 amp hours at a 20 hour rate that means the battery can be discharged from full to empty over 20 hours @ 5 amps. It gives us a base to equally look at the battery capacity. The faster you draw power out of the battery the less usable power you will have and the inverse is the same, the slower you draw power out of the batteries there will be more available to use. It’s the same idea as driving a car. The slower you drive and are gentle on the throttle the better fuel mileage you have. 

     Depth of Discharge is important as well. We will see which batteries can use more of their capacity. Depth of discharge is thought of from 100% full down to 50% used. That’s an example of 50% Depth of Discharge or DOD. 

The cheapest option out the gate for RV Batteries is the simple 12Volt Deep Cycle Battery.

You can even find these at Walmart but because of them being a bit of a hybrid battery, deep cycle and starting, It can be hard to find the capacity. Typical capacity is 75 amp hours for an RV battery of this type. The depth of discharge recommend at 50%. That means you only get to use about 35- 38 amp hours which isn’t that much. It’s important to know when you discharge your lead acid battery like this it begins the process of sulfation. The longer your battery stays discharged the sulfation that builds up on the plates begins to harden. Best practice is to charge it as soon as possible to allow the sulfation to come off the plates and start the process all over again. This type of battery will not have a long life if you let it sit discharged and if you don’t maintain it. This battery needs frequent maintenance by checking the fluid level and properly filling it with distilled water. To take it a step farther it would be best to check the fluid specific gravity with a Hydrometer.  The reason these batteries need maintenance is because they also need to vent. They vent very toxic gases which is why they are in a vented compartment or in a vented outside box. 

6 Volt Golf Cart Batteries

Next on our list of batteries are the 6 Volt Golf Cart batteries. A single 6 volt battery will not work in an RV so we have to have  two and wire them in series. It is fairly simple all we have to do to wire in series is to connect the two  batteries together with a cable from the positive of one battery to the negative of the other. Any load or charger is then connected to remaining positive and remaining  negative on the battery bank. When you wire batteries in series add the voltage of the batteries together so 6V+6V=12V. On the capacity side of the equation you do not add them so if you had a pair of 6Volt batteries each with 235 amp hours, once you connect them together your battery bank is still at 235 amp hours. The opposite  would be true if we had a pair of 12 volt batteries. We do not want to change the voltage, so the positives of the batteries are connected together on one side and the negative terminals are tied together on the negative side. So in the case of parallel connected  battery bank we do not add the voltage so it remains a 12 Volt system and we add the capacity together. So if it was a pair of 12 volt batteries at 75 amp hours each our battery bank would be 12 Volts at 150 amp hours. These 6 volt batteries are much better at handling  the deep discharge but still require the same maintenance and venting. 

AGM or Sealed Batteries

AGM Batteries are a big step up in convenience. They no longer require you to maintain the fluid level in them. They don’t vent the same way but under certain conditions they can still “off gas” so it is best to still use them in a vented space not in the indoors of your RV.  They handle the deep discharge well. Some manufacturers say you can take them down to 75% DOD and not harm them but the amount  of cycles you get out of them will not be as good as if you keep it at the 50% DOD cycle.  It is important to remember once you draw your batteries down you will want to charge them as soon as possible to keep them in good working order. 

Lithium LiFe PO4

The last battery on our list I imagine will be the go to someday as they are better in performance in just about every way. They are lighter (half the weight at 30 pounds), the cycle expectancy is 5x more(will last for a very long time), charge much faster and efficient, depth of discharge is much deeper, and the list can go on. We have the Battle Born Batteries and I don’t have much of anything bad to say about them. As they are newer and last much longer the price up front is much higher. The main things to consider when switching to lithium is you no longer have to vent them and actually it is better to have them in a conditioned space. If the temperatures are too low you will damage them when you charge them but lead acid batteries can freeze too if they are empty, so freezing temps for any battery is a bad thing. Also you will need a charger that works well with Lithium. Battle Born has a list of all the chargers  that work well, so if you are thinking about making the switch it’s worth looking at the list and what you already have seen . The same goes for the other battery types, I recommend  upgrading your Converter Charger to a three or four stage converter to take care of your batteries better and charge  them more efficiently . you can check out our Video on Smart Converters for more info.These are just the highlights of Lithium, there is so much they can do. We will save some of the other info for another post