I am designing a circuit that will be powered by two rechargable coin cells in series, and I need to include a module to recharge them in-situ.
I have had a look on RS at the range of rechargable coin cells and it seems that there are two variations with regards to the chemistry; Lithium Vanadium Pentoxide and NiMH.
I am trying to determine suitable charging circuits for both types of batteries, bearing in mind that there are two cells in series. I am having trouble finding any example charging circuits, particularly for the Lithium Vanadium Pentoxide battery, which I am most concerned about as I know some types of Lithium battery require specific charging cycles.
What do these batteries require from a charging circuit?
Are there any things that must be avoided when charging these batteries?
Can you reference example charging circuits and/or charging IC's for these batteries?
Extension: I have also found lithium-ion coin cells that have a nominal voltage of 3V.
Please can you advice me how to design a charging circuit for a pair of these in series?