Weird issues with different voltage of batteries

[FrancisZ]

Hey all. Been running my cart a little since I got it. It’s a 1999 36 volt club car resistor cart. I used it quite a bit today (maybe 10 miles total) and noticed it started to slow a lot. I wanted to run it down because I was curious to check the voltages at the end of a charge. Really weird what I found:

1- 4.94
2- 4.91
3- 4.93
4- 5.92
5- 5.94
6- 5.91

It seems odd to me that the first three batteries are so close in voltage and the last three are so close. All the date codes are the same on the batteries. What could I be missing? I guess my next step is to mix the batteries up (keeping the wires the same) and see if I just happen to have three bad batteries or I’m getting some weird draw on the first three in series. The batteries are 2018 Trojans. I don’t think there should be anything wrong with them yet.

[jakesnake27]

Were you driving backwards the entire time?

In all seriousness, that's all I can think of- these carts use 18v for reverse, unless yours has been wired for full speed reverse. Also, with those readings, your batteries are severely discharged. Do not run your pack below 50% SOC regularly, as permanent damage will occur to the batteries.

Here is a handy SOC chart: