re: Can I charge a 48 volt battery with a 12 volt charger?

short answer no.


long answer, your charger is outputting 12 volts. 4 12V batteries in series is 48V like you said therefore you can not charge them that way. In theory, you could put them in parallel to charge them all at once. Practically this probably won't work because your charger won't have the current capacity to charge all 4 batteries at once.

you probably wouldn't damage the charger if you have tried to charge them, because most likely the charger has a diode blocking higher voltages from driving back into the charger.

Just use the charge as it's intended and all will be ok.