Van Life Battery Calculator & Comparison Table

Graham Bogie

This battery life calculator and comparison table allow you to compare up to 3 batteries to help choose the best batteries for your camper solar panels set up.

It’s simple and straightforward to use. We’ve included a section below to answer some questions you may have.

This calculator forms part of our camper solar panel setup series and the wider subject of campervan electrics

And it’s just one of our electrical calculators for RVs and campervan conversions too.

Before you start, use our solar battery bank calculator to work out how much energy you’ll use each day.

Then shop around for a few batteries.

When you’ve found 2 or 3, use this battery life calculator to work out how cost-effective they are and how often they’ll need replacing.

Then you can choose the best battery for your DIY campervan conversion without too much guesswork.

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How Do I Use This Battery Life Calculator?

  1. Enter a name of each battery you want to compare
  2. Enter the total ah of the battery bank
  3. Enter the number of cycles each battery can provide
  4. Enter each battery’s expected lifespan in years
  5. Enter the price of each battery
  6. Select the comparison period from the dropdown list
  7. Enter your expected daily power usage in watt hours

How Many amp Hours Do I Need?

If you haven’t already, use our solar battery bank calculator to work out the minimum size battery bank needed to meet your usage.

Remember, this is the minimum needed and you can install more if you want to.

You can enter as many amp hours as you like in the calculator.

We recommend playing with the numbers in the calculator because a larger battery bank may reduce the overall costs.

Does The Battery Bank Have To Be The Same Size For All The Batteries?


You may not need the same size lithium-ion battery bank as you would AGM, Gel, or FLA. 

And you may not be able to get the same size batteries for all the types you want to compare. 

For each battery type, enter the total battery bank size in amp hours (ah).

How Do I Find The Cycles Of Each Battery?

Manufacturers provide an indication of the expected lifespan of their batteries in cycles.

Battery specifications are normally available online on manufacturers’ and resellers’ websites.

The Cycles Are Given As A Range. Which Should I Use?

A battery’s lifespan is based on how many times it is discharged to a specified depth of discharge or DoD. This is called a charge cycle.  

In a controlled environment, manufacturers test batteries to give an indication of their performance.

1 battery cycle is defined as using 100% of the battery.

For example, if you use 30% of the battery one day and it is recharged to 100%, then use 50% the next day, then 20% on the third day, you’ll have used and replaced 100% of the battery charge. Or 1 battery cycle over 3 days. 

If the manufacturer has given the cycles as a range, use your best judgment. 

If comparing batteries from the same manufacturer, be consistent in which end of the range you use.

If in doubt, we recommend using the lowest number to give the worst-case scenario. You can always use the calculator again to work out the best case too.

How Do I Find The Lifespan In Years Of Each Battery?

Manufacturers provide an indication of the expected lifespan of their batteries in years as well.

Battery specifications are normally available online on manufacturers’ and resellers’ websites.

The Lifespan Is Given As A Range Of Years. Which Should I Use?

As with the cycle range, use your best judgment. 

I Want To Install More Than 1 Battery. What Numbers Do I Use?

If any of the battery banks consist of more than one physical battery:

  • Use the total amp hours (add the ah of all batteries together)
  • Use the cycle and lifespan in years of one battery
  • Use the price of all the batteries together

What Currency Do I Need To Use?

It doesn’t matter which currency you work in.

Use the same currency for all batteries though so you can compare like for like.

Can I Compare Different Types Of Batteries?


Battery 1 could be a Lithium, Battery 2 a Gel, and Battery 3 an AGM. 

We have designed the calculator so you can assess the different types of batteries and how they’ll affect your maintenance & overall costs.

Can I Compare Similar Batteries From Different Manufacturers?


The calculator is quite basic. It doesn’t know or indeed cares what batteries you enter. The calculation is the same.

So let’s say you calculate first the difference between a Gel, AGM, and Lithium. You choose Gel.

Then you find 3 different Gel batteries and you want to know which is best for you.

Enter their specifications and run another comparison.

What Is The Comparison Period And Which Should I Select?

When calculating the cost and number of times the battery will need to be replaced we need to understand over what period of time you want to measure this.

You should choose the number closest to the amount of time you expect to own the camper.

How Do I Find Out My Daily Usage In Watt Hours?

Calculate your daily usage with our solar battery bank calculator

How Can I Use The Comparison Table To Decide Which Batteries Are Best For Me?

The calculator works out the total number of times you can expect to replace each battery during the comparison period and the total cost based on the prices you’ve entered.

Remember, this isn’t an exact science. 

Battery prices will vary over time for one thing. Your estimated usage and even the manufacturers’ specifications aren’t precise.

But it’s all good enough to be indicative and help you compare one battery with another.

When we decide on what batteries we’ll fit in our campers, we look at both the expected overall cost and how many times we can reasonably expect to replace them.

Then we look at where we’re likely to travel and make a call on how easily we could get replacements.

Quite often, we find the longer the comparison period, the less significant the price variance. But while price becomes less of a deciding factor, the number of times they need to be replaced varies more.

In 10 years, you wouldn’t expect to have to replace lithium batteries but would probably be on a 4th or 5th set of AGMs.

What you decide on from there is up to you. 

Need More Help Calculating Your Campervan Electrical System?

Here are the links to our other calculators:

Graham Bogie

Graham Bogie - Expert in RV & Campervan Electrics - Mowgli Adventures

Graham is a seasoned marine electrical engineer with two decades of experience designing customized electrical systems for plant machinery and converting campers and overland vehicles. His expertise has led him to author the reputable Campervan Electrics Handbook and become the chief designer of our Campervan Electrical Design Service. As a knowledgeable figure in the field, his YouTube channel, blog, Facebook group, and newsletter, offering electrical advice and product reviews, reach more than a million users each year.

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