i have been running 48 volt sla batteries, with a 12 ah rating. i noticed my low voltage light comes on and the bike starts cutting out after only using 5.25 a/h (as per a watts up meter). Is this normal or do i have a battery problem? The batteries are about 3 mo. old.
It's normal. Unfortunately lead acid batteries will give their full number of amp hours if you use them gradually over 24 hours but if you use their capacity up in one hour they'll only give about half their rated amp hours.