2008 GEM display shows no charge

I need some help with a charger or display problem with my 2008 GEM 825. The “state of charge” indicator on the display is showing only a single red bar, meaning charge is less than 10%. But the Delta-Q charger is working normally – I can watch the charger display go thru the bulk and absorption charge phases, to finally get a charge completion indicator. The batteries are now at about 76.3 volts. Each battery is 12.73, 12.64, 12.64, 12.85, 12.71, 12.77v, and I have load tested each battery with a 100A load tester, with results of 11.63, 11.55, 11.52, 11.89, 11.66, 11.72v under load.
I took the cart for a 5-minute run, and rechecked the battery stack at 75.9v, and each battery is 12.67, 12.60, 12.61, 12.79, 12.67, 12.68v. The charger profile is correctly set for #13 for my trojan flooded batteries. Then I ran the charger until complete. It goes thru the charge phases normally. After an hour to rest, I checked the battery stack at 78.4v.
However, the state of charge indicator is still showing one red bar. The cart will move normally for a short distance, and then goes into turtle mode, so we limp back to the garage. Battery stack is still at 78v. HELP!
Is the display or PDSM missing a critical signal to measure battery voltage? Which module actually contains the voltage measuring circuit? And how do I diagnose the problem? Is there some sort of interlock not working?

It is possible that something is wrong, but first try what @AssyRequired posted in another thread (there are lots of threads about charging, did you search?)

If you have never reset the SOC indicator it just may need recalibrating.

Resetting the SOC meter should be done when your pack has finished it’s charge cycle. Verify by plugging in the car and making sure your charger fully goes to green light (on the CHARGER Display, not the dash display). Do you know where that is?

You can reset the meter by using the following steps:

  • Turn the key on.
  • Push and release the TRIP/ODOMETER switch until it’s showing the
  • While holding the switch down, turn the RIGHT signal on, then the LEFT
    signal, then return the blinker to the center.
  • Release the TRIP/ODOMETER switch. You should be seeing data (P0105) on
    the display now. This number may be different depending on your display firmware loaded.
  • Turn the RIGHT signal on, then off repeatedly until the display reads:
    SOC (State Of Charge).
  • Push and release the TRIP/ODOMETER switch. Now it’s remaining capacity in percent.
  • You can now raise (or lower, for that matter) the SOC with the blinker
  • When you’re happy, Push and release the TRIP/ODOMETER switch. The display reads: DONE.
  • Turn the key off.

*Ignore all of the other settings in the secret menu


any thoughts on using the battery load tester to take those 2 higher voltage batteries down to the same as the others? The idea is to do a full charge, run the cart around until you’re getting around 12.60 for the highest battery and then using the load tester drain the 2 highest voltage batteries down to the same voltage as the 4rd highest battery. In the above list battery 4(12.79) and 6(12.68) would be run down to 12.67V.

You really want your batteries to be pretty equal in voltage give or take .08V. Battery 4 is almost .20V higher then the others and that can just get worst as charge cycles start adding up.


Hi Rich. Welcome to the fun and frustrating world of Gem Cars!

I was looking at these battery voltage levels too. Thanks for taking the time to test and post your info to this detail.

I agree - This pack needs a good balance session.
What is the history of this pack?
Is this a new car to you?
Depending on how you answer these questions it may direct where to go next.

I think adding volts via an external car charger is easier than dropping it with the load tester, as it is more hands off. Put the charger on the low ones and let it go through it’s cycle. See if they will come up and stay the same as the higher batteries. If not, then they are the weak links in your chain.

Once you get the pack balanced you can use the onboard Gem charger to give them another hit. Let them cool off and settle down to their resting voltage THEN you can Reset the SOC using the instructions listed above ^^^.

Also note that when the car is plugged in to charge the Dash Display should show a little yellow plug and the battery display should animate and the car will not drive when you turn the key(this is known as the charger interlock). This needs to happen for the SOC to operate properly. If it does not do all these things then it has been bypassed for some reason and you need to find out why.

The full battery bars may make you feel better but it probably shouldn’t be trusted until you are sure your pack is not tired/damaged/flogged like a tired donkey in it’s previous life.
Take the car on a few short runs and measure when you get back.

The 100a load test is only a small picture of what is happening to these packs when driving. Your car may draw up over 200-300A when accelerating and pulling hills. Try hooking your meter probes to the POS and NEG of your controller and monitoring the PackV as you are driving around and see how far your pack ACTUALLY drops.

First look from here, your pack looks and sounds weak. A huge V drop when running is what is triggering your turtle after your 5 minute drive.


Thank you for your (gentle) advice about the SOC function. I was so wrapped up about getting the battery pack in shape, that I overlooked this reset. Replacement batteries had been installed, then I found a bad battery, replaced it, worked to equalize, then realized the Delta-Q charger was not set for flooded batteries, fixed that issue. Next I used your method to reset the SOC and it worked! Thanks for the help. Next step is to do a better job equalizing the batteries.


Anyway to reset this with earlier models i.e. 2000-2004? I don’t have a TRIP/ODOMETER button on my carts. Or do I?

Thank you.

Nope. This feature isn’t on the older T1 & T2 carts.