🚀 go-pugleaf

Since the great quake of '89 in S.F., preparation for "the big one" here
in SoCal has been reawaken from its slumber. In this regard, I have several
radios and flashlights in which I use rechargeable batteries. Since the
rechargers for these batteries have ac transformers, which would be useless
when power is out in an emergency. I'm planning on buying some solar cells
for recharging these batteries. Is there a formula for determining the
amount of charging voltage and time for a rechargeable battery based on its
rated voltage? Any tips or suggestions?
                                                    - MJB -