Lithium vs Lead Acid – Which battery is best for a Van Conversion?

Which battery is better for a van conversion, lithium or lead acid batteries? what are the advantages and disadvantages of each battery and which is best for a van build?
Lithium vs Lead Acid – Which battery is best for a Van Conversion?

The best battery for a van conversion depends on your electrical needs. Lithiums are best if you plan to use a lot of power, whilst lead acids are better if you’re on a budget and don’t need a lot of power.

Campervan electrics is a tricky topic, and when you’re starting out can feel overwhelming at times.

Even something as simple as choosing your battery, there are many things to think about.

This short blog will run through the advantages and disadvantages of lithium vs lead acid batteries and help you decide which battery is best for your van conversion.

How much battery power do I need?

Before deciding which battery type is best for you, you need to determine how much power you would need.

Firstly, estimate your potential power usage – to calculate how many Ah/Watts of battery storage you need. Use this calculator to help you.

This will give you an indication of how big your batteries will need to be to support your electrical needs.

We explain a lot more about this in our understanding campervan electrics workshop.

Once you have this rough amount of power written down, you can then start to look at batteries and their pros and cons.

Personal Battery Calculation

We calculated we’d use around 80-100Ah/day of power for a high usage day and knew we wanted to be off-grid for at least two days at a minimum.

Our power usage was quite high since we use laptops to work and would use some electrical cooking appliances.

This meant we needed 200Ah minimum of power.

Originally, this 200Ah of lithium power was enough, but as we upgraded our campervan to use more electrical cooking, especially after getting an electric oven, we realised we needed to increase our battery capacity a lot.

agm lead acid battery van conversion essential

Lead Acid Batteries

Lead acid batteries are the original batteries used in campervans.

They have been used for over 150 years, and their technology hasn’t changed much simply because it works.

There are many types of Lead Acid Batteries (flooded lead acid, gel lead acid, AGM lead acid, Lead-Carbon), but for this post, we will focus on AGM Lead Acid, as this is by far the most common battery type, and is what most people mean when they say lead acid.

Positives of AGM Lead Acid Batteries

  • Cheap. Lead Acids are very cheap to buy and replace. If something goes wrong, or you mess something up, it won’t break the bank to replace. (Cost: £1/Ah)
  • Fully Recyclable. All lead in these batteries is made from recycled lead and can be 100% recycled into new batteries.
  • Easy. Lead acid batteries in one word. They don’t require anything special or any monitoring system. They are plug-and-play.
  • Remaining power. To measure lead acid batteries remaining power, you just need to measure the voltage. 12V = 50%. No tracking or other devices are required.

Negatives of AGM Lead Acid Batteries

  • Short Lifespan. Generally, lead acid batteries last three years before they lose their efficiency.
  • Only use 50%. When Lead Acids are at 50% remaining capacity, their voltage is 12.0V. Going below 50% can end up damaging the batteries. A 100Ah Lead Acid battery only has 50Ah of usable power.
  • Heavy. Lead Acid batteries are very heavy compared with lithium batteries. In a van where weight consideration is constant, this is important to note.
  • Slower charging/discharging. If you want to pull a lot of power quickly or charge it quickly, lead acids don’t like it and it can damage them.

Who Are AGM Lead Acid Batteries Best For?

Lead Acid batteries are best if you if:

  • You are only taking short trips out.
  • Don’t require lots of power.
  • Have a small budget and can’t afford lithium.
  • Will be parked at campsites with access to external hookup power.
lithium battery van conversion essential

Lithium (LiFePO4) Batteries

Lithium Batteries (Lithium Iron Phosphate – LiFePO4) are the newer battery technology for campervans.

These batteries are much more energy dense and can handle high power outputs, so they are great for full-time off-grid adventurers.

Whilst more expensive, if you have the budget, they are the future and the way to go, especially in campervans.

We went with Roamer Batteries’ lithium batteries in our build when we upgraded our battery setup, and we can honestly say they have improved our campervan experience ten-fold with their reliability.

Positives of Lithium Batteries

  • Long lifespan. Lithium batteries can easily last 10-15 years if you take care of them. Our Roamer batteries even came with a 10-year warranty! Not something you’d find with lead acids.
  • Use 100% of power. 100Ah of lithium means you can use basically 100Ah of power. You can drain these batteries to nearly 0%, and it won’t damage them.
  • Lightweight. Lithium batteries are 3-4x lighter than lead acids, and if you need a lot of power, this can be some serious weight saving for your campervan build.
  • Faster charging/discharging. You can often pull much more power at once from lithium batteries and charge than a lot faster than lead acid batteries as well. Great for electric cooking.

Negatives of Lithium Batteries

  • Expensive. The biggest downside of lithium batteries is their cost. Although they are getting cheaper, they still cost 4x more than lead acids. (Cost: £4/Ah)
  • Requires Monitoring. Most lithium batteries require a battery management system to keep them safe (most come with one built-in). You also need a BMV to track all the power going in/out of the battery to calculate their remaining charge, which is extra wiring to do.
  • Cold charge problems. If lithium batteries drop below 5C, charging them quickly can permanently damage the battery, which is a costly mistake. Roamer batteries have an Xtreme range which can deal with this issue, but it’s an extra cost.
  • Replacement is more difficult. Not only are lithium batteries much more expensive to replace, but you can’t just go into a store and buy one off the shelf. You need to order online or go to a specialist.

Who Are Lithium Batteries Best For?

Lithium batteries are best if you if:

  • Want to go off-grid for a long time.
  • You are planning to use electric cooking appliances.
  • Need a lot of power.
  • Want to future-proof your campervan setup.

    Lithium vs Lead Acid – our opinion

    Personally, we think that everyone should go with lithium.

    The only exception would be if you have a very small budget and only need to run a few electricals like lights, charge a phone, or run a water pump.

    Lithium batteries are getting cheaper every day, and as technology improves, they will become cheaper still.

    Despite the cost, lithium batteries are longer lasting, more reliable, can provide more power, save weight, and you can build some behemoth electrical systems!

    We will do an entire blog dedicated to how to pick the right lithium batteries to buy, as there are important considerations you need to account for, along with a review on our Roamer batteries that we bought to upgrade our system to 920Ah of lithium (spoiler, they’re great).

    As long as you take care of lithium batteries, they are the future for campervan electrical systems.


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