LiFePo4 charger ?

[soundcheck]

Hi guys.

I'd like to build a LiFePo4 charger for A123 cells.

The batteries are supposed to replace some 3,3V
voltage regulators. The charger should be part
of the device. I'd prefer to skip external chargers.

Has anyboy done that? Any DIY infos about it?

Thx
Cheers

[abraxalito]

I've got a schematic for one which I haven't tried out yet. I'd be happy to share it here if there's interest. Seeing as it hasn't been built or tested, there are no guarantees

[kevino]

I'm just starting a project to do this sort of thing using a Microchip MCP73123. It's
a tiny surface mount IC but only requires a few extra components. There's a dev
board with both a 1 cell and 2 cell charging circuit that I've just received.
Ideally, I'd like to build a flexible cell-power management module that could be
assembled into multi-cell configurations.

Kevin

[luka]

hmm, to bad is isn't balancer too
be sure to post anything here, I have few of those A123 too
And if your up for it, if you would do some test one for me, I think those china ones are fake

[kevino]

well, if 3.3v is all one is after - as soundcheck mentioned - then this solution is perfectly balanced;-) seriously though - i'm after a 'balanced' multi cell configuration but might
try simple single cell chargers will relays rather than a 'complicated' circuit

[luka]

or few of this circuit in series, each with its own floating supply, that will work too

[kevino]

hi luka, can you explain about "each with its own floating supply"?

Thanks, kevin

[luka]

picture one charger by itself. now if you have 2 or more, you can join one + and one - of other battery to form pack of 2 batteries, connected in series. But each has it own charger... now I don't see, apart from price tag, that you could do 100 like so in series