[mozer]

I have just purchased a RAC Smart Battery Charger HP239 and its not so smart I have some small 12 Volt 6 cell lead acid batteries that are not totally flat ie 10 to 11 Volts remaining and will still drive a 12 volt compressor so they still have some Amp power to them.
the problem is it will not recognize any of the said batteries as 12 volt. I have tried boosting them up to to just above 12 volts then connecting up to do a full charge to NO avail, any one got any ideas.

[Santa]

AFAIK the "smart" thing is simply that they stop charging when the battery is fully charged. It may be that it thinks your batteries are already charged sufficiently at 10/12 volts.

Cheap equipment is usually worth what you pay for it.

[wagolynn]

Doe's the charger warn you if you have connected the batteries the wrong way round?

If not, are you connecting them the wrong way round?

Have you tried connecting the batteries in parallel (+ to +, - to -) this doubles the capacity, the idea is to make them look more like a car battery to the charger.

If that does not work, try it on a car battery, if it works then the charger is too smart to be fooled by the smaller batteries (you make them sound smaller).

OR simply take it back, or contact customer support.