Bicycle water pump + battery charge

Hi there Bio-people!
I've made a pedal water pump, thus for filling a water tank... Quite new, don't have statistics yet, but only that 20' is not enough for pumping 500 liters... but I believe almost...
I'd like some help on how could I do to get some extra advantage of the excercise, since I have to do it anyway, in order to help charging the batteries (usually charged by solar pannel).
Thanks a lot, and here a pic of the stuff.

You want to pedal harder? A battery will do that for you!

If you wire a 24 volt electric scooter motor to a 12v pwm charge control, and drive the motor with your sproketry, you can charge a 12v battery.

Check polarity with a meter first.

Hello Manuel Munilla, first of all great work done. You can charge a 12v battery as frank li mentioned.