Bongo Fury

I have 2 bran new 12 v 45 ah sealed gel batteries which were bought for an electric wheelchair but not used. Can I use these as a ;easure battery in my Bongo, and charge them with the split relay. does any one know if they are different to ordinary leasure batteries?

Possibly but .....
The normal charging voltage for a wet lead acid battery is 14.2-14.5 Volts.
For Gel type battery the recommended charging voltage is only 13.8 Volts.
If you let them charge at the higher voltage, then the release valves will open to reduce the pressure that would otherwise build up, but that will eventually lead to there demise.
Having said that there are some types of Gel batteries that can withstand up to 16 volts but they aren't very common, normally used in fast charge setup's where the charge time can be controlled.

Plenty of info. available on Wikiedia http://en.wikipedia.org/wiki/Gel_battery#Gel_battery and for standard Lead acid http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery

thank you very much for the information. I shall have a read of the link you sent and maybe learn something. Seee you at the bash