# How many batteries can I charge and how long would it take?

Using a hydro generator which gives an output of 4.838KW, I am trying to figure out how many batteries I can charge and how long it would take.

I am doing the calculations based on 12V, 17Ah batteries. this is for a theoretical large scale operation so i am therefore looking to charge between 25 and 100 batteries.

If an extra generator is necessary this can be factored in, however the core of this question is to figure out the ration between power output it watts and charging of multiple batteries in V & Ah.

If anyone could help it would be very much appreciated.

## 1 Answer

P = VI

You have a 4838 joule/second input, and a system that holds 12 * 17 Ah = 12*17*3600 =734400 joules of energy

so, if you need 7.344 K joules of energy, and your input is 4.838 J/s that's 734400/4838 = 151.798263 seconds to get that energy

Now the real challenge is that you probably can't charge a battery that fast- I'm a mechanical engineer, so I can't give you specifics, but you need a charge controller that limits the amount of current going in to your battery, otherwise they could overheat and start a fire