Formula Question

Amp hr capacity multiply by the voltage of the pack gives me the watt hrs of the pack.

That tells me how many watt hours a given pack has.

Now if the pack was drained completely I would need to put back in that amount of wattage correct? So if I have a 36 volt 23ah pack I need to put back in 823 watt hrs of juice right? Now how do I calculate how long it would take to put back 823 watt hrs?

Matt

Amp

watts = volts x amps, volts = amps x resistance. amp hours is a capacity measurement of the battery. watt/hours = volts x amp/hours.. Most chargers are constant current for agm batteries. If you are using a 36 volt charger that is 3 amps it will fill your battery at the rate of 36volts x 3 amps/hr = 108 watts/hour.. It will take this charger about 8 hours to charge a 828 watt pack,, 828 watts divided by 108 watts/hour = 7.66 hours

[b]AGM BATTERIES[/b]

THANK YOU!!!!!!!!!!!!!!

THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!

THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The calculations are correct but they leave out the loses. There is normally some loses in the form of heat when transferring energy from one source to another. I don't know what the lose would be in this case but I would make an educated guess of 20 to 30 %. These looses would add to the charge time so the 7.66 hours would be more like 7.66 x 20 to 30%. I will use an average of 25% and the new time would be 1.25 x 7.66 = 9.579 hours.

Chas S.

My Bicycle Pages