Lithium Battery Installations

The last few years have seen a massive increase in Lithium battery installs, and with it has come a massive range of options.

The references below are for 12V if you have a 24V setup, just double the numbers. I want to focus on two areas today, Charge current and Charge Voltage. 

There are a lot of mains chargers that now have a “Lithium” battery option. Unfortunately, these are not suited to all Lithium batteries.

I can’t recommend strongly enough that if you have Lithium batteries you should at a minimum know the Max Charge Voltage and Current for your batteries, why, because if you are exceeding one or both, you are likely damaging and significantly reducing the life of your batteries, as well as voiding your warranty, and yes most batteries will be data logging the max’s being seen.

This is a generalization, but for the most part, the lower the max voltage and charge current the lower the quality of the battery.

Again a generalization, most chargers with a non-programable Lithium setting will be set to a charge voltage of around 14.4V, again you should have read the charger spec and know it matches your battery, it’s not enough that it has a Lithium Profile!!

There are battery brands in the market whose max charge voltage is as low as 14.0V or less, so you really do need to read your spec sheets and be sure your gear is matched.

The same applies to Solar Controllers as for Mains Chargers and DCDC units charging via alternators.

Pretty much the same applies for charge current, I have seen recommended charge rates as low as 20amps, which is roughly equivalent to the peak 300W of solar can deliver or a 20amp mains charger.

Again if you exceed the charge current recommendation, you face shortening battery life and voiding warranty.

Yes, they should have a BMS, but these need to allow for peaks which are usually only for a few seconds, you can’t rely on the BMS, you need to have the appropriate equipment to look after your batteries.

 

Having said all of that, there are also plenty of Lithium brands that allow a range of charge voltage which by design are the same as most AGM profiles, this has allowed many many owners to do a direct swap out from AGM to Lithium without having to change any other hardware.

If you don’t know your specs, please take the time to look them up and write them on your battery, so if anyone is ever working on them they will know what to check for.

 

You may need to buy a compatible charger but I can assure you it will be cheaper than replacing your battery prematurely.

One quick example, a recent customer had purchased a common brand mains charger sold at a national vehicle accessory store, it had a Lithium Profile, so was purchased and connected and after a relatively short period, the customer started having issues, upon doing some research the battery was found to have a max charge voltage almost 1/2 a volt lower than the Lithium Profile on the charger, now I can hear some of you saying 1/2 a volt is not much, but I can assure you it is enough to damage SOME batteries, particularly over an extended period.