2012 Precedent discharging

ncfenceguy

Hi guys and Merry Christmas !!!! I have a question that's been on the back burner for awhile. 2012 CC Precedent randomly discharges while sitting. The cart in question sits for about a week at a time and usually gets driven on Sundays. OBC is still connected and it is using the old style charger (non ERIC). Batteries are 2016 AC Delco in decent shape. Main pack voltage and individual batteries all test in range for their age. About 1 time out of 5 (5 weeks of Sundays) when we go to get on the cart, the voltage has dropped to the mid 30s despite being continuously plugged up to the charger. No accessories on the cart and it doesn't seem to make a difference is the key switch and the run/tow switch are off. Resetting the OBC didn't make a difference either. Most weeks its at 49 volts at rest. Taking it off the charger for a couple days it will hold voltage without being plugged up. I'm suspecting the OBC but didn't know if it can actually discharge the pack. I've been wanting to do away with the OBC for some time but have become interested in the lithium conversions being talked about on the forum, so not quite ready to buy a new smart charger only to not need it when my current battery pack dies. Thanks !!!!

BGW

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yawood

Have you checked the tightness of all the cables?

I would remove the cable end from each terminal in turn, thoroughly clean each one (including the cable end) then replace with a good smear of vasoline or other terminal grease. I would also check the tightness at the controller, solenoid and motor. When checking the motor use two spanners so that you can make sure that the stud does not turn as you tighten the top nut.

Keep an eye out for any burn marks that would indicate a short. If there is any in a cable, replace that cable.

Test the voltage on each battery and keep a record as well as a record of the total pack. If the total pack voltage drops again, check and record each battery individually. It may be that one of the batteries is going bad.

Your pack voltage is not great indicating that the batteries are closer to the end of their life than the beginning so it's possible that an individual battery is dying. For example my three year old US Battery pack still shows 50.9V after I have played 18 holes of golf. See the attached chart for what you should expect.

And of course make sure that they have water and you don't have any dry cells. Also make sure that the tops are clean so that they are not discharging across a dirty battery.

It may well be something else but what I have detailed above should be done first just to eliminate those things as a problem.

Oh, and Merry Christmas to you and yours.

Attached Images

State of Charge Table.jpg (84.9 KB, 0 views)

bobwalter

Are those batteries 12 volt AC Delco?. Not sure they make golf car batteries. Check them to be sure. Sound like someone put 12 volt starting batteries in it. If so, I think that is your problem. Starting batteries do not have the necessary amps to last in a golf car. Check each battery with a multimeter while driving. Hook probes to a single battery, set meter on seat and drive. Write down the reading. Then hook to next battery and do the same. I think you will find that one or more batteries is reading very low. You may need new batteries. When replacing, do not use starting batteries. Maybe your lithium conversion is coming sooner than you thought.