Building A Battery Bank
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The very first thing we upgraded on our RV was the batteries.
There are so many options to choose from that making an informed choice can seem elusive.
After doing loads of research, we decided to go with two Interstate 6-Volt Deep Cycle Golf Cart Batteries wired in series.
“Wired in Series” means that you are multiplying the voltage into one big 12-Volt Battery by connecting a cable from the negative on one battery to the positive on the other (the two posts left are your negative and positive for hooking your RV up to).
We chose the Golf Cart batteries because they are true deep cycle batteries which means that they can be discharged up to 80% and then fully recharged without damage. RV/Marine Batteries would be destroyed by this.
Most RVs come stock with 12-Volt RV/Marine Batteries. Even though these batteries are labeled by manufacturers as “deep cycle”, they are actually a hybrid starter/deep cycle battery.
Those are usually fine for folks who are plugged into shore power like at RV parks. However, if you are doing more extended trips like boondocking or incorporating renewables like solar, you will probably want something better for your battery bank.
A few options out there are:
Absorbed Glass-Mat (AGM) Batteries.
Lithium Batteries
Golfcart Batteries (6-Volt deep cycle)
AGM and other VRLA (Valve Regulate Lead Acid) batteries keep the acid electrolyte solution immobilized by soaking it either in a fiberglass mat (hence the name) or by turning the liquid into a paste-like gel by the addition of silica and other gelling agents. These batteries are called “Gel Batteries”.
The one benefit of using AGM Batteries is that they will hold a charge much better than traditional flooded cell batteries. This means an RV can be stored for months at a time and the batteries will stay charged because they discharge very slowly unlike traditional lead-acid batteries. In regular lead-acid battery cells, the acid is in liquid form and can evaporate much faster.
The downside of AGM batteries is that they cost nearly double what traditional lead-acid batteries cost. And they weigh more. Another drawback is that it is not possible to inspect or fill AGM batteries. This means they won’t last as long as properly cared for flooded-cell batteries. This is because AGM batteries still out-gas.
Lithium Ion-phosphate batteries are all the rage in battery technology today. They are fantastic batteries as there are a lot of benefits that come with using them. They charge much faster than lead-acid batteries. They have more capacity and weigh less. Lithium batteries have a more consistent power discharge and a deeper depth of discharge. Best of all, they last a lot longer.
The downside to Lithium batteries is that they are way more expensive. Sometimes up to 10 times more expensive than regular lead-acid batteries and 5 times more expensive than AGM. But, if you can afford to make the investment, they are the ultimate upgrade for RVs, especially when using Solar Power.
In this process of upgrading our batteries, we discovered that our RV came with a Converter Charger, which is what most RVs come with, stock. Converter Chargers convert AC into DC to charge up your house batteries when your RV is plugged into shore power. The problem with Converter Chargers is that they will boil your batteries because they send a constant charge of 13.7 Volts. An overcharged battery will boil the sulfuric acid and distilled water mix and the battery will no longer hold a charge.
So, knowing what we know now, we would recommend that you start your RV upgrades by replacing your onboard Converter Charger with a 3 Stage (Absorption, Bulk, Float) smart charger/inverter.
This one upgrade will then preserve the life and performance of your batteries and protect your investment, saving you hundreds of dollars in the long run.
The Smart Charger Inverter we went with is the Xantrex Freedom HF 1800. It’s one of the smallest, lightest, and most affordable Smart Chargers on the market and it works really well. We highly recommend Xantrex Freedom! Click the image below to use our affiliate link!
The Freedom HF Inverter/charger is available in two sizes: 1000 watts with a 20-amp charger and 1800 watts with a 40-amp charger. Both Freedom HF models are designed for demanding marine and RV conditions. Temperature-controlled multistage charging ensures that your batteries are recharged safely and efficiently.
With modified sine wave output, Freedom HF Inverter/Chargers are designed to run entertainment systems and small appliances in smaller boats, RVs, and trucks.
Having an inverter allows you to access the power in your batteries through the AC outlet on the unit so that when you are not plugged into shore power you can do things like charge your phones and computers or operate small appliances like blenders and power tools.