I am developing a backup power system to power a controller using a (12V 7AH LiFePO4) battery (BA50-1) which is replacing a lead acid one. Although the battery has a built-in BMS I would like to integrate a controller which has an input from a power supply and outputs to both the battery and the load (The load only requires a maximum of 1.2W). This device needs to be able to output the constant current and constant voltage required to charge a lithium battery correctly. I have found it difficult to find a single PCB to handle all these applications. Does anyone know of a product like this or a suitable alternative?
Assuming I’m looking at the same product spec you are, the BA50-1 battery is designed and marketed as a direct replacement for sealed lead acid cells of the same form factor. You should therefore be able to use it as such, including selection of charge adapters.
So long as the chosen device functions to limit charge current and voltage to less than the stated maximum values, the built-in BMS should take care of the rest. These limits are within the range common to automotive trickle chargers, of which the “dumbest” will probably be a better choice. (Stay away from anything with a “desulfation” function) PCCG-SLA12V1800 might be a good selection.
Thanks for the feedback I’ll check out the products you sent. They say direct replacement but in reality most lead acid chargers don’t even meet this batteries minimum current level to even start charging the thing.
Could you provide a reference to the portion of the product specification you’re referencing?
Any charge source exceeding the ~1mA self-discharge rate should produce an increasing state of charge.
“Smart” chargers however may interpret a LiFePO4 battery at low state of charge (or disconnected by the BMS) as defective/unconnected however, and refuse to activate their output. Hence the suggestion to look for a “dumb” charger.