Battery Charger

Are the 3 cells wired up in a pack, so in series? That makes life harder.

If they're separate (or can be separate) then I'd just use 3 MAX1555 chips.

In fact if you're not trying to get the charger to be small and you do have cells in series I'd consider just buying 2 isolated DC-DC converter modules and powering the MAX1555 chips through those. Nice and easy, and safe :)

But yeah, a nice little multi-cell LiPo charger board would be great. I wonder how many people would be interested. My wish list was:

• Charges 3 cells, maybe 4.
  
• Small enough to fit inside the battery pack
  
• Charge via Micro-USB
  
• A button and RGB charge status LED
  
• Potentially a FET-switched output that could be turned on and off via the button - so if you wanted to make (for example) a torch, you could easily get a 'soft' on/off button.
  
  

The implications of it going wrong do worry me, although if all the LiPos have some kind of protection in them now then I guess it's not as bad.