Battery Problems US 8 volt

[bigstik40]

Originally Posted by hooknup

So that one battery can drag the whole cart down like that. Do you know if the US batteries have any type of warranty.

One bad battery in the series string can cause the whole pack to look bad. Your pack is only as good as the worst battery. Also check for loose, corroded connections. - Good luck - Ray

[JohnnieB]

Unless the battery store specializes in golf cart batteries, they probably tested that battery with a SLI (Start-Lights-Ignition..... aka car battery) type tester rather than a load tester specifically designed and calibrated for deep cycle batteries, so you still don't know if it is good or bad.

As I mentioned, the 0.5V variance is troublesome, but until otherwise proven, it only means that the pack is imbalanced and needs to be equalized.

To equalize the pack, charge the pack until the charger shuts off automatically.
Unplug charger from cart for at least ten minutes and then plug charger back into cart.
When the charger shuts off automatically again, disconnect it for at least ten minutes and plug it in again.
After the charger shuts off for the third time, drive cart about 500 yards, then let it sit for about 30 minutes to allow the battery voltage to recover after being discharged, then measure the pack voltage and the individual battery voltages.

The pack should now read 53.1V and each battery should read 8.55V. Hopefully the variance will now be less than 0.5V.

Drive cart a few miles, or until it start getting sluggish, then wait 30 minutes and measure the pack and individual battery voltages again.

How far the voltage dropped depends on distance driven and efficiency of the cart, but the variance should be the same, or mighty close to the same.

If it is the same, the problem isn't a weak battery, it is a whole set of weak batteries.

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You haven't identified the charger being used, but if it isn't one with a US Battery charging profile, your nearly two year old batteries have likely been chronically undercharged for their entire life and may very well be at the end of their usable lifespan.