2008 Electric club car not sure whats wrong

[slee44708]

Ok so here we go my 2008 electric club car runs great for 10 to 20 minutes then it starts slowing down, but yet me battery voltage is still up. I let it sit for 5 minutes or so then it runs fine for another 10 minutes or so. Any ideas maybe the controller going bad?

[OLD MEC]

GO BACK TO BASIC'S DONT THINK JUST BECAUSE BATTERYS ARE ONLY 2-3 YEARS OLD THAT THEY ARE GOOD. Have you load tested or hydrometer tested batterys? Either you are unhooking charger before its done, or you have bad cell or cells in batterys?
Do you have a single float hydrometer with temperature correcting scale ( NOT A ANTIFREEZE MULTI FLOAT UNIT ) if so after charging battery pack until charger turns off and WAIT one hour for pack to stabalize test and record readings on each battery cell and let us know what they are. REMINDER if you have added distilled water since last charge wait until after next charge and then allow one hour and do same as above.
A load tester used as instructions show will give you an idea of battery condition and if you have a bad cell or battery it will show a much lower drop during test.
I have used the hydrometer test since getting into auto mec in the mid 1940s and find it works and gives me batterys condition and rate of charge without depending on meters or dash guages.
REFER TO STICKIES ABOVE FOR "STATE OF CHARGE CHART READINGS"