It's quite simple ... A 90 Amp hour battery is rated that it (under ideal conditions) could run at discharge rate of 90 amps for 1 hour! If completely flat all you have to do ...divide the 90amps by 4(amps) will take around 22 hours to re-charge. It's far better to trickle charge batteries than give them a whacking great belt....especially these days with complex ECU's fitted to most Cars. So the 12 volt 4 Amp battery charger is ideal.
It's quite simple ...A 90 Amp hour battery is rated that it (under ideal conditions) could run at discharge rate of 90 amps for 1 hour!If completely flat all you have to do ...divide the 90amps by 4(amps) will take around 22 hours to re-charge.It's f