Converting NiMH battery to Li-ion in mobile phones

[bialasikk]

Hi!

I love old mobile phones. I have really huge collection, but sadly really big part of them have NiMH batteries (and most of them are dead now).
It's really annoying because I have a lot of phone's batteries from newer phones; most of them are Li-ion. Cells inside are perfect in dimensions but it's totally another type of battery - another levels of charge, another algorithm for charging...

I have a question - is it possible to make a NiMH -> Li-ion converter? It will be small board which will be a 'bridge' between old charging system in phone and new cell inside battery. If it's possible, have you got any ideas how can I make it?

Thanks,
Marcin

PS. that my first post here, main Polish electronics forum (elektroda.pl) is really unfriendly for new users and questions like this, so nice to be here!

[jeroen79]

I suppose it is possible.
You will need to make a two way dc dc converter that will on one side (dis)charge the Li-Ion within it's limits and on the other side mimic a NiMH, taking a (presumably) constant current charge and then doing something to indicate that it is full.
Without knowing how exactly the phone does the charging this will be difficult to get right.

Can you not find new NiMH cells?
They're not extinct yet.