Use our RV Battery Calculator
Welcome to our RV battery size calculator, a free tool designed to help you estimate your RV’s daily power requirements and the battery size appropriate to meet those requirements. Ensure that you have sufficient battery power from the installed battery bank.
I hope you read my article on RV Battery types. If you did, you understand the different types of RV batteries and their pros, cons, and limitations. If not, take the time to find the best battery type for your needs. Now, it’s time to determine the quantity and capacity of the batteries you need for your RV battery bank.
To do that, calculate how much power your coach uses when not plugged into shore power. Then, you need to convert this total power consumption value to a rated RV battery measurement.
RV Battery Size Calculator
How to use the RV Battery Size Calculator to Choose RV Batteries Correctly
In the first part of the RV battery size calculator, for every appliance you intend to power on board your motorhome or travel trailer, enter the quantity of each and the amount of time you estimate you will have them running on an average day. You will produce a grand total of your daily power usage.
Finally, enter the number of house batteries you plan to have in the coach and the type of battery you are considering. The latter is essential because different battery types have different discharge capabilities.
The calculator will return the amp-hour rating for each battery. I recommend oversizing this number when you decide on batteries to have some headroom for excess usage or electrical additions to the coach.
Note: We have used wattage values slightly higher than the average for each load in this RV battery size calculator. However, it would help if you double-checked each wattage rating on your appliances. I know this sounds like a lot of work, but having sufficient power is essential to your safety. You don’t want an undersized battery bank; you want the best RV battery configuration to protect you and your loved ones.
My Picks for the Best RV Batteries
For a complete list of recommendations for RV batteries, see this article.
RV Battery FAQs
How do I know what size battery bank I need for my RV?
Determine your RV’s power requirements and calculate the battery bank size accordingly. Consider factors like power usage, appliances, duration of usage, and desired battery autonomy. I recommend consulting a professional, but you can use our free RV battery size calculator above for a reasonable estimate of the needed size.
How do you calculate RV battery needs?
To calculate RV battery needs, follow these steps:
Determine the total power consumption of your RV appliances and devices in amp-hours (Ah). This information is usually found in the user manuals or the appliances.
Estimate the hours you typically use each appliance or device per day.
To get the daily amp-hour usage, multiply the amp-hour consumption of each appliance by the number of hours of daily use.
Add up the daily amp-hour usage of all appliances and devices to get the total daily amp-hour consumption.
Consider how many days you want your battery to last without recharging.
Multiply the total daily amp-hour consumption by the desired number of days to get the total amp-hour capacity required for your RV battery.
Consider the battery’s depth of discharge (DoD) rating, which indicates the percentage of the battery’s capacity you can safely use. Multiply the total amp-hour capacity by the inverse of the DoD to determine the recommended battery capacity.
To ensure you choose the right RV battery size, consider additional factors such as temperature, battery efficiency, and future power needs.
In our RV battery size calculator above, we factor all of these considerations in to obtaining the battery size needed.
Note: It’s always a good idea to consult with a professional or reference specific battery manufacturer guidelines for accurate calculations tailored to your RV setup.
The RV battery size calculator above considers all of these variables when recommending a battery size for your bank.
How long will a 100 amp hour battery last in an RV?
This depends on the battery type and the wattage the RV is drawing. The time also depends on whether or not the charge replenishes the power used. Use our RV battery size calculator above for a more accurate estimate of your RV power needs
How much battery power do I need for my RV?
The battery power required for an RV can vary depending on your specific needs. Still, a standard recommendation is to have at least two deep-cycle batteries with a combined capacity of 200 amp-hours (Ah) or more.
However, this is highly dependent on your RV setup and configuration. Use the RV battery size calculator above to get an accurate estimate of the battery power you need.
