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 don't 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.

 

[alphysicist]

I would like to clarify that the fastest way to charge a battery is not solely determined by the voltage or wattage of the solar panel. It also depends on the capacity and condition of the battery, as well as the charging method used.

However, in general, a higher voltage solar panel will charge a battery faster than a lower voltage one. This is because a higher voltage can push more current into the battery, thus charging it quicker. The "ohm's law" that your friend mentioned is relevant here, as it states that the current (I) flowing through a circuit is directly proportional to the voltage (V) and inversely proportional to the resistance (R) of the circuit (I = V/R).

In this case, the resistance of the circuit is determined by the battery's internal resistance, which varies depending on its condition and age. A higher voltage solar panel can overcome this resistance more easily, resulting in faster charging.

Therefore, in the scenario you provided, the 24v 100w solar panel would be the better option for charging a 100ah battery. However, it is also important to consider the safety and compatibility of the solar panel with the battery and charging system. I recommend consulting a professional for specific recommendations and proper guidance.