Charging times.

[davelectronic]

Times come for me to find a charging solution for a mobility scooter in a Lockup garage that has no power points. I've come up with two SLA batteries in parallel, powering an inverter and the scooter charger. My two SLA batteries are 12 Volts and 110Ah each, so I'm going to put them in parallel. The mobility scooter is powered by two 50 Ah batteries in series, so the scooter is a 24 Volt system. The part I'm struggling with is, as my journey times vary, I can't work out how long I need to charge from the inverter to scooter charger through the two SLA batteries. In recent times (emergency) I have charged the scooter via one SLA 12 Volts 110 Ah battery, this managed approximately 3 hours charge time via the inverter to scooter charger. I'm not asking for the numbers to work this out, more the formula to assume an average maximum charge time. The charger for the mobility scooter charges at 8 Amps, but drops to 4 amps as the charge nears completion. So once I've charge the mobility scooter through the SLA batteries, I then take the SLA batteries indoors to recharge the pair of parallel SLA batteries, ready for the next charge. Any help appreciated and thanks for reading.

[madires]

That sounds like a quite inefficient solution. And the batteries need to be replaced every few years. Is it feasible to get mains power to the garage, to get a garage with power, or to install a small PV system?

[davelectronic]

I agree it's inefficient, but I'm in a tower block, and my elevator is out of service for 3 months. There is no way I can get a power point installed, these are council community lock ups with no power in any of them. I will have to use the alternative elevator on the next floor down two flights of stairs. My Son is going to use a sack barrow (stair climbing varient) to get the two batteries down the stairs. I've tried to find another solution. But I'm out of ideas.