Hello,

I am wondering if I can charge my double A (1.5 V) battery directly from the 12 V lead-acid battery by connecting them in a parallel connection.

Is it dangerous or not recommended or OK at all?

Thank you.

 

No! You must not attempt that. Your AA battery will overheat and explode due to the high current.

 

OK. Thank you for the information. How about a 9 volt dry cell to a 1.5 volt dry cell (the same dry cell) connect each other in parallel. Will the 1.5 volt battery charge?

 

Do not connect batteries of different voltages together with wire, as a fire or explosion will result.

If your AA battery is NiCD or NiMH, you need to use a proper charger that will regulate the voltage and current supplied to the battery for charging.

You should not attempt to charge other types of AA batteries.

 

Dry cells are not rechargable, but 12V battery can charge Ni-Cd AA by connecting a 100Ω, 2W resistor between them. Remove when warm or 10 hours.