Tim Lamb wrote:
Is there any essential difference in charger specification for gel
batteries fitted to motorised wheelchairs as opposed to conventional
lead acid?

Yes, gel electrolyte battery chargers have better output voltage and
current control than normal chargers.

For cheapness, Maplin do a couple of chargers suitable for gel
electrolyte lead acid batteries.

http://www.maplin.co.uk/power/batter...acid-batteries

You may need to sort out a connector to match the one on the chair.

Check the voltage used on the chair, too, as I think some of them are 24
volt, not 12.
--
Tciao for Now!

John.