Lithium iron phosphate (LIFePO4) battery charger

After two DIY Li Ion chargers this week (first, second), here is a lithium iron phosphate (LIFePO4) battery charger. These batteries are a safer cousin to the standard Li-Ion batteries, but sacrifice some of it’s energy density for the safety. The charger above is designed around the PIC12F510 microcontroller which implements a rudimentary USB powered pulse charger.
This entry was posted in Lithium Ion and tagged battery charger, LIFePO4, USB.

Comments
When I saw the title, I was hoping for something a little bigger. I’m considering buying a 300Ah 12v LiFePO4 set that should outperform a 450Ah set of lead-acid batteries. My motorhome (that I live in full time) has a pair of 6v 225Ah batteries, The solar controller is programmable enough for the LiFePO4, but my 55A converter/charger needs hacked for them.
I’ve seen LiFePO4 12V batteries that were advertised as directly compatible with lead-acid 12V batteries, using the same charger. Maybe for the higher amp-hour categories that is not true. They are certainly more expensive, per amp-hour. For some types you get lower internal resistance, eg. higher peak output current. I would think a 300 Ah battery could deliver some scary currents. I have used a much smaller 4 Ah LiFePO4 (two 26650 cells in parallel), which can deliver over 100 A. Not indefinitely, but for long enough to get the spot-welded end tabs red hot…
“Pulse Charger” just makes me cringe given the awful state of USB port power supplies.