Fastest way to charge a battery?

Panamanian

Say you have a battery 100ah and you want to charge it the fastest way.
What's better? if you have a solar panel 12v 100w or a solar panel 24v 100w
(all at the same amperage rating).

I thought the 12v 100w, but a friend is telling something about the "ohm law", which I dont know. Could you please guide me? or let me know?

Muchas gracias.

sophiecentaur

What is the voltage of your battery? You should charge it from a source that is nominally the same voltage. (i.e. 12V battery - 12V charger, nominally) But it will depend upon the type of battery. Is it the lead acid type (they are fairly tolerant about how you treat them)? If not, then you should buy the appropriate charger.
There is a lot of information on this link. It would be worth scanning through it even if you don't follow it completely as it shows just how complicated the charging of batteries can be.

Panamanian

Oh yeah Sophie, the battery say it'd be a car battery 12v rated at 100ah (GEL BATTERY).
what would be the fastest way?

gnurf

If you hook a 12V battery straight onto a 24V/100W solar panel, you'll clamp the solar panel at the battery voltage and not fully utilize the 100W. On the other hand, if you follow Sophie's recommendation you'll operate the solar panel closer to it's maximum power point and hence be able to utilize all (read: more) of the rated 100W. Getting from this basic idea to an efficient solar charger is another story.