RV Battery WiringBattery Wiring

This article focuses on RV Battery Wiring and other aspects of 12 Volt Deep Cycle & 6 Volt (Golf Cart) Lead Acid Batteries, including maintenance-free lead-acid batteries. Other battery types are AGM, Gel Cell & Lithium-Ion. Lead Acid batteries are the least expensive batteries and adequate for most RVers. It is always best to talk to an expert to help decide what your needs are and what the best solution is.

12 Volt Deep Cycle Batteries – The most common size or series are the 24 and 27 series. These are the most common sizes used in RVs for house batteries. Deep Cycle batteries are not used for starting engines, also known as cranking batteries. Deep Cycle RV Batteries typically are rated @ 70-90 amp hours depending on the battery brand and size; if there are two batteries, the amp-hour rating doubles. Although the discharge rate is approximately 50% per battery, an AGM could be 80%, and a Lithium-Ion battery could be 90%. Of course, these numbers can vary depending on size and brand. With two 12 volt batteries, if one battery fails, you will still have 12 volts to power your RV. This is not the case with 2 6 volt batteries; you will only have 6 volts if one fails.

Amp Hour example, a 100 AH battery will give you 1A for 100 hrs, or 5A for 20 hrs, or 10A for 10 hrs, or 100A for 1 hr, etc. In practice, though, it is found that batteries deliver less capacity at higher discharge rates, meaning if you discharge it over a shorter time, then you get less capacity.

24 Series Approximate Dimensions: 10” L x 7” W x 8” H – Not including top posts.

27 Series Approximate Dimensions: 12” L x 7” W x 8” H – Not including top posts.

6 Volt Golf Cart Batteries – 6-volt batteries are not usually installed on new RVs and have become a popular upgrade due to the higher amp hour rating (225 +). They typically have a longer life than 12-volt deep cycle batteries. 6 Volt batteries are considered more durable than the 12-volt deep cycle battery.

Golf Cart (6 Volt) Approximate Dimensions: 10” L x 7” W x 9.5” H – Not including top posts.

Are all Batteries Equal – No, even if they come out of the same manufacturing facility, there can be differences in quality? Some large retail chains want their batteries made to lesser specs to be more competitive with pricing. This is standard practice with Automotive batteries and across all categories, from food to computers.

6 volt Batteries in Series120 volt ParrallelBattery Wiring – Parallel & Series: Parallel Increases Capacity and Series Increases the Voltage. Parallel wiring is the standard method for more than one 12-volt battery. The technique doesn’t increase voltage regardless of how many batteries are added to the battery bank.

6-volt batteries used in an RV application need to be used in sets of two. With one 6-volt battery, you can’t power the 12-volt system in an RV. Although, two 6-volt batteries wired in series create 12 volts. You can 6 volts in multiples of two to build more capacity, and when wired correctly, the voltage will remain at a safe 12 volts.

Battery Cable Size: Assuming the positive cable from the RV to the battery is the correct size, any additional cables to connect 12-volt batteries should be at least the same size or larger. The only downside to a larger cable is that it could be harder to work with and a little heavier. When using 6-volt batteries, it is recommended to use no smaller than a #2 cable for wiring the batteries together. You can use a larger cable if desired. Remember that the larger the cable, the harder it is to work with.