16 volt scooter batteries

[electrondady1]

my friend bought one of these little scooters. it's a 48 volt using three 16 volt batteries
he let them sit all winter inside without charging  and now they are dead. he left them on the charger over night bu still nothing . any advise ? any sources of new battery's?

[electrondady1]

so anyway these are sealed lead acid batteries.
they still produce the proper voltage
could they have discharged so badly over the winter as to render them now useless.?

[Mary B]

Yes that can kill a battery when it self discharges and then freezes crushing the plates together and causing shorts.

[electrondady1]

they  didn't  freeze, they were sitting in his house.
when he first put then back in the scooter they had no power to even  light up the instrument display
 i put my meter on them and he's getting 50 volts.
i don't think the cells are damaged
just really discharged.
but i don't know anything about sealed battery's.
the scooter came with a smart charger .
i told him to leave it on for a couple of day to see if they can come back.

[Norm]

you're getting 50 volts....so does it run the scooter at all ?
Just because it has a smart charger doesn't mean the charger is smart 
If it runs the scooter at all how long does it run it before it fades ?
what is the amp/hr rating ?
Norm 

[electrondady1]

http://huazhenggroup.com/products/8-dzm-14-ID77.html#.U1f3Byhvf3U

[Mary B]

50.93 is fully charged, he may have a different problem.