Is one 300 Ah lithium or three 100 Ah batteries better? What size converter?

Dear Dave,
I decided to go lithium and am familiar with the install, but I have a question on batteries. Currently I have four 6-volt golf cart batteries and am okay with power availability, but slightly more would be better. I see a lot of batteries at 270-300 amps, but I cannot get a clear answer on what’s best: one 300-amp or three 100-amp lithium batteries? I have room for either. I’d like to hear your views and ideas. Thanks again. —Alan, 2018 Winnebago Vista 29VE

Dear Alan,
Great question, and it gave me the opportunity to contact a few of my lithium battery contacts as well as Dennis from Progressive Dynamics. I asked about the one versus three scenario, and also for an explanation regarding the different amperage converter/chargers.

From Expion 360

I would suggest the new 162ah GC2’s. Two of them will give you 324ah. If one battery goes down, you still have 162ah to use until your camping trip is over. This should be easily expandable to a 3rd GC2 down the road, which would give you almost 400ah of power at that point. The GC2’s are some of the hottest new batteries that OEM’s are using throughout the industry. In comparison, Battle Born’s GC2 is only 100ah. The new GC2 from Expion is the highest rated GC2 in the industry.

Back to Dave

What is GC2 and what size converter should it have?

Expion 360

The GC2 is a well-known BCI size (Battery Council International). It is technically a golf cart battery designation simply because of the footprint or case size/dimensions. This allows us to pack more of our high capacity 4.5ah cells into it. The recommended charge for our batteries is 25% of capacity which on one battery would be 40ah, two batteries 80ah, etc.

So, yes, we would recommend a higher capacity converter charger if it makes sense. If the unit typically charges overnight, it’s not as big of a deal. But if you need to rapid charge your battery bank in order to get back to off-grid camping, then sizing your converter-charger, inverter-charger, solar system, etc., accordingly is always recommended.

From Battle Born Batteries

There are a few things I look at when helping a customer decide which amp hour battery might be best for them.

Here are a few thoughts that come up with this type of question:

What is your ultimate goal with a lithium upgrade?

Asking this question goes a long way. Some customers just want a little more run time compared to what they were getting with LA [lead acid] batteries, and nothing more. Some customers want to start small, then over time add more batteries to a system until they can ultimately run whatever they want, as long as they want. If they are only looking to get around 300ah I normally push them to (3) 100ah batteries. But if there are plans to add more batteries to run large appliances, I tend to lean towards larger single batteries.

Something about Battle Born Batteries: If you bought a battery from me today, you have two years to add more batteries to that existing system. For example: You purchase (3) 100ah batteries from me today on 1/24/2025 but your ultimate goal is to have 800ah for your system. You can buy those (5) extra batteries over the course of 2 years without causing any issues. Allows customer to “build as they go” and it’s very useful.

Redundancy: It’s always nice to have some redundancy in an electrical system, especially when boondocking/dry camping. Most customers often lean towards a (3) 100ah setup so that if anything were to occur with a battery while in use, it could be removed and still have 200ah of battery left over. It’s always good to prepare for adverse conditions while boondocking.

High Energy Systems: Customers who have large coaches, for example, something like a large Class A motorhome wired for 50a service, most commonly see benefit in using larger capacity batteries. These would be situations where you need to run one or more air conditioners from a battery bank, or other large AC load appliances. When designing large systems like this, we tend to lean customers towards larger capacity batteries.

From Dennis at Progressive Dynamics

For a multiple battery configuration I would consult with the battery manufacturer as to your best option. Some manufacturers recommend no more than two batteries in parallel and others may allow for up to four batteries. In any case, fully charge the batteries individually before combining them for parallel operation.

The amperage differences between chargers will affect the amount of time it takes to fully charge the battery (bank).

A few factors should be considered when choosing a charger that will work best for you. Although the amp hour rating of the battery bank is important (you don’t want to exceed the recommended charging rate for a low capacity battery), the amount of time it will take to charge the bank is also of concern. But more important to me is the AC power source.

A charging system with optimal charging efficiency (no more than a 2% loss between the charger and the battery) will require maximum AC power consumption in the charger. For example, a 60-amp charger requires a little more than 1000 watts of AC power, or about 11 AC amps. The bare minimum AC requirement is a 120V/15A service. This could be the 15-amp outlet at home or a minimum 2000-watt generator; whereas, an 80-amp charger will require a little more than 1300 watts or about 15+ amps. That would suggest a 20-amp AC outlet or a 3000-watt generator.

Remember, when you are boondocking you have to look at the worst-case scenario.  After all, a 30- or 50-amp hookup is not available in the middle of nowhere.

 You might also enjoy this from Dave 

Is lithium ion or lithium iron phosphate battery better in RV?

Dear Dave,
What’s the difference between a lithium ion battery and a lithium iron battery? Is one safer than the other for a 33′ 5th wheel? —Troy, 2005 Alfa See Ya

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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