Just to add some info on the float chargers I have, both CTEK brand. one I use on the Morgan the older of the two is suitable for use on older type wet lead acid batteries and is pretty simple having a charge mode for motorcycles and by comparison larger car batteries, it also has a float mode for long term low level charging
The other CTEK is specifically designed to cater for both lead acid and has a selectable option for AGM batteries, it has a multi stage programme option for small batteries and normal car sized batteries similar to my other charger, it also has a reconditioning option which may off-set the effects of long term float charging as Richard pointed out. I believe that AGM batteries operate at different voltages to older lead acid wet type batteries and that applies to in-car charging too, which may make swapping out an old lead acid and replacing with an AGM in some way problematic, in that it may be the case that old style car charging circuits may not bring an AGM up to it`s full charge requirements to ensure max capacity and perhaps longevity..?
The dual charger I use is a CTEK MXS 5.0 the 5.0 relating to it`s maximum charge output in amps, there will be plenty of info on line.
Good luck in your choices.
