off-grid RV camping

Increasing Your RV Battery’s Capacity and Overall Runtime

On Overlanding adventures where primitive campsites don’t have power hookups, your house battery may not be large enough to provide the power you need for the length of your stay.  On these occasions, one definitely does not want to run out of power for lights, cooking, or charging mobile devices. So if you’re venturing out into areas without power to plug into, it’s easy to add more battery power and run time if you have space.

Deep-Cycle Batteries and Amp-Hour Ratings

Many RVs come with a single 12-volt battery dedicated to the unit’s house power. To increase the capacity, you first need to make sure the battery is a deep-cycle model. Some RVs are outfitted with a typical automotive starter battery which works fine to provide lots of initial power to start an engine, but not for maintaining power over several hours for lights and other electrical accessories. Switching to one 12-volt deep-cycle battery is a start. It will provide power for a longer period of time, indicated in amp-hours (usually the 20 hour capacity in Ah).

Amp-hour ratings are shown on the battery label and will help you figure out how many discharge amps the battery can provide for however many hours you need to supply.  Here’s an example. The most common rating is the 20 hour capacity in Ah or rate in amps.  The capacity in amp-hours is found by multiplying the discharge time (20 hours) by the discharge rate.  The discharge rate is found by dividing the rated amp-hour capacity by the discharge time (20 hours).  For example, a battery that is rated at 100 amp-hours at the 20-hour rate would have a continuous discharge rate of 5 amps for 20 hours.  Similarly, a battery with a rating of 100 amp-hours at the 5-hour rate would have a continuous discharge rate of 20 amps for 5 hours, but its 20-hour capacity would be much higher than 100 amp-hours (probably closer to 130 Ah at C20).  When selecting a battery for a given application, it is important to use the rating that is closest to the average runtime needed between recharges in the application.  That, combined with knowing the total amperage your electrical accessories in your RV will draw, will help to determine how much battery capacity you will need.

Two-Batteries Are Better Than One

If you switched your house power to a deep-cycle battery with a greater amp-hour rating but find you still need more capacity, you can add another battery in parallel if you have space. Adding a second deep-cycle 12-volt 100 amp-hour battery connected in parallel, for example, will keep the voltage the same at 12 volts but will increase the capacity to 200 amp-hours.  This can double the discharge rate (10 amps for 20 hours) or simply run the system for a longer time between recharges.

If you have a large enough space in your RV to add more batteries, you can add a third 12 volt – 100 Ah battery connected in parallel.  However, it is not recommended to make more than three parallel connections.  If even more capacity is needed without increasing system voltage, another method is to connect 6-volt batteries in a series/parallel circuit.  Six-volt golf car deep-cycle batteries are designed with much higher capacity per battery. (200 – 250 Ah each).

Two six-volt batteries can be connected in series for 12 volts and then another set of two connected in parallel for 400-500 Ah or a third set in parallel for 600-750 Ah at 12 volts.

The difference in wiring batteries in series and parallel can be seen here. If you plan on attempting this upgrade, make sure to use high-quality large-gauge wiring and connectors, and talk to an RV electrician for any help in setting up a multi-battery bank system. Some systems like this need to be separate from the RV’s charging and electrical system. It will also require you to use a good-quality battery charger specifically for large capacity deep-cycle batteries. If Overlanding is a long-term lifestyle, many have also considered adding solar panels to the top of their RV to keep deep-cycle house batteries charged and provide consistent power when they need it.

While upgrading to more batteries is more expensive, the larger battery bank will lower your depth of discharge (DOD) on each battery to the recommended 50% or less. This will ultimately enable the pack to last much longer than constantly draining a single battery.



Deep-Cycle Battery Tune-Up Tips

Aside from routinely adding water and charging your deep-cycle batteries, battery manufacturers recommend giving your batteries a tune-up. Simply put, this consists of a few methods to check the condition of the deep-cycle batteries and the associated components so that everything can continue to run perfectly.

Battery Terminals and Wires

1) Safety first. Always perform battery maintenance in a well ventilated area and wear eye protection and gloves.

2) Open the battery compartment of your deep-cycle battery-powered vehicle and check the wires and terminals connected to the battery. If corroded, clean them with a mixture of baking soda and water to neutralize acid corrosion (easily done with a spray bottle). Remove the cables from the battery terminals and, using a wire brush with a plastic or wooden handle to prevent shorting, clean the terminals and wire connections down to the bright metal. Replace any wires that are frayed or broken.

3) Reconnect the cables to the battery terminals. The recommended terminal torque is 100-inch pounds or 15-18 pounds on the end of a six-inch wrench. Avoid using larger wrenches or power tools.  Lead terminals can easily be damaged by over-tightening.  The goal is to fully compress the split-ring lock washer but no more. Use insulated tools to prevent arching.

4) Once the terminals and cables are clean and connections are secure, use silicone spray or a corrosion inhibitor to prevent additional corrosion from forming.

Condition of the Batteries

1) Remove the vent caps on each of the deep-cycle batteries and check the electrolyte level in each cell. If some are low, refill with distilled water so that the plates are covered with at least ¼ inch of electrolyte before charging.  After charging top up to within a ¼ inch of split-ring level indicator.

2) Use a hydrometer to determine the state of charge for each battery. During winter storage, all of the batteries should have been stored in a fully charged state. Check the battery manufacturer’s recommendation for the fully charged specific gravity for each type of battery.

3) If the batteries are fully charged, the vehicle is ready to start service. If the batteries are not fully charged, connect the charger and let it run through a full charge cycle. After charging recheck the electrolyte level and use a hydrometer to verify the batteries are at full charge.

4) After the first 30-days of use, perform an equalization charge to balance the cells and to mix the electrolyte to  prevent stratification.

Once you’ve completed these steps, your deep-cycle batteries in your golf cart, aerial work platform, forklift or even your RV and boat, should be ready to go back to work. With regular maintenance, they will continue to run at optimum performance and last longer with lower annual operating costs. For more information on deep-cycle batteries for your particular application and maintenance tips, visit



RV Batteries, Getting The Most Power Storage

Most RVs have an electrical system that simply plugs into a power source. When you’re at a more primitive site that has no power or water, your RV’s deep-cycle batteries had better be in top shape to power everything from your fridge, lights, stove and more. Many RV owners don’t always think about their batteries until they stop working, so it’s always important to make sure you have enough energy storage to power all your RV’s accessories. 

The way to ensure your RV has plenty of standby power is to ensure the batteries have enough capacity to handle the power load of all of your RV’s accessories. First, It’s important to know that RVs require a deep-cycle battery for this purpose. These batteries provide longer lasting power compared to regular car starter batteries that are designed to provide maximum power for short periods (to start the engine). Each deep-cycle battery is rated in amp-hours (AH), a measurement of the battery’s capacity. Most are indicated in the amount of current in amps that the battery can provide for 20-hours. 

For example, a deep-cycle battery with a 100 AH rating can deliver 5 amps for 20 hours, or 20 amps for 5 hours, before being discharged. Discharging deep-cycle batteries more than 50-percent will dramatically shorten their life. This is one reason why many experienced RV owners use batteries with the most AH rating they can get. When comparing batteries, make sure you compare them by the same 20-hour standard.

RV owners also switch to using multiple batteries to provide extra capacity. In many instances, this is done by using two smaller 12-volt deep-cycle batteries wired in parallel that will increase the AH capacity rating and leave the voltage at 12-volts. If you really want to dramatically increase your power storage, you can also switch to using two 6-volt batteries that need to be wired in series to produce 12-volts. This can more than double your AH capacity if you have the battery storage space to do so. 

Keeping your batteries from being discharged below 50-percent is key to making them last longer, as can checking the water levels in the batteries. In some RVs, it’s difficult to access the batteries for monthly maintenance so some RV owners also install a single-point watering system that makes it easy to add water to each battery from one access point. 

For more information on selecting the right RV batteries and maintenance tips on making them last longer, visit