So you think Samsung have battery problems?

[Nick]

I am working on a way of safely charging dodgy Li-Iron batteries and will start a new thread when I have sorted it out with or without the fireworks.
Testing so far has come up with a dodgy battery that charged without exploding a few times before it began to de-laminate internally causing it to bulge and become difficult to insert into the device.

The chemistry of Lithium-based batteries is complex and quick to anger - really, you should not under any circumstances attempt to resurrect suspect units - it's just dangerous - a false economy.

As the charging profile is complex, subtle (must be exact), dangerous (if you get it wrong) and generally requires load-balancing at a cell level and sensor feedback, e.g. thermistors buried in the pile, several of the standard chip manufacturers produce ranges of cheap ICs that do all this for you. Phone batteries have exactly this - they are not just a LiPo stack.

e.g. Maxim make over 70 different charger ICs, some of which are universal, i.e. chemistry-independent. 

https://para.maximintegrated.com/en/sear...=batt_chrg

...also Linear Technology: http://www.linear.com/products/Linear_Battery_Chargers

One huge plus for the Linear Technology devices is that they provide full Spice models and examples for LTspiceIV - you can model the behavior of your design for free. I'm a big fan of LTspice and use it as my Spice of choice, as do 100s of 1000s of other engineers. And it's free

The App Notes for these chips are very good - I have used Maxim power management ICs in several designs - other manufacturers also have similar.

Whilst the appeal of doing this yourself may be great, I would encourage you not to - there is a lot of wrong and plain bad information on the www - and what works for you (some or even most of the time) may well cause a fire for someone else.