Quote Originally Posted by Ingvar View Post
I would say this is not a very good method, the heat is produced when you are overcharging(read damaging) the batteries. The whole idea is trying NOT to overcharge. Go with the delta V method, it also works by detecting overcharging, but a lot faster, cheaper and more reliably. Monitoring the temperature is done in "high-end" chargers for safety reasons, don't want the batteries to go "kaboom".
Thank you Ingvar!

So, when you have PIC18F4550 and you monitor your batteries in every case, it is easy then also to follow the delta V and wait for the slope first to go to zero and and then turn slightly to negative, or perhaps just wait for the moment when your voltage is not more growing. One could check also the temperature and why not put a time window also, to be perfect

There is no need to monitor the current during the charging...
Or what could one gain by doing so?

However, there are better(???) systems. Found one that is called Burp charging, also called Reflex or Negative Pulse Charging, for example
you can find:
http://www.powerdesigners.com/pdf/Ne...nd%20Facts.pdf

This raises another question.
If your application has batteries (nominal 7,2V) and you will charge them by plugging a 12V/800mAh charger to the batteries. If you would like to build a Burp charging system you would need to build a discharge system also to your application... how could one do/build that, a discharge resistant or perhaps a discrete circuit that could do it. With how big current should one do that? Is Burp better or not than just delta V, temp and time window. One would think that you, to be perfect, need temp. and time also whatever charger (if not slow C/10) you use...

There are a lot of information floating around,
the only problem is that you have not build before such a charging(/discharging) systems,
and so you lack the practical experience...

PS. how empty can a new 1,2V cell be discharged before permanent damage? Is it the same for an old one, near the end of it's life? Any differences between different battery manufacturers?