The 12 Volt, 100 Ah LFP battery has become a commodity. There are lots of vendors (most being Chinese) selling similar batteries for $250 or less. Are they any good?
The short answer is “it depends”. Some use cells that are not “automotive grade”, some have a Battery Management System (BMS) that is not capable of doing its job at current and temperature limits and some are just poorly made.
When you buy such a battery you are buying a plastic box with four LFP cells inside, a BMS and some wiring. Very different from older lead-acid batteries.
What we don’t know is which batteries are top quality and which suck. This video takes a look at one of the choices on the market. Besides showing you what is in the Siekon battery (and how it performs) it also shows you how to evaluate a battery. I’m not suggesting you buy a bunch of batteries, take them apart and see how they perform but this particular video does a good job of showing how to evaluate a battery. There are lots of videos out there so you can use this as a standard when watching others.
One thing not mentioned in this video is connecting batteries in series. For example, if you have a 48 Volt inverter you will need four 12 Volt batteries connected in series. While the built-in BMS will make sure the cells in a battery are balanced, you will generally need a BMS connected to all the batteries in the series string to make sure the individual 12 Volt batteries are balanced.
