'09 GEM BDI will not reset after charging

Hi all, hoping someone can give us a tip that may help us. We service electric vehicles and this '09 GEM came into us with old stone dead batteries. We replaced the GEL batteries with new AGM batteries. We also found that the charger was bad so we replaced it and reset the algorithm for the batteries to charge correctly. Everything seems to be working well with the exception of that after fully charging the batteries we have to manually reset the BDI (battery discharge indicator) gauge in order for the gauge to read fully charged. If we do that and drive the vehicle the gauge will go down along with the actual charge of the batteries but if we recharge the batteries the gauge will remain at the level it was at when discharged. Then again we would have to manually reset the BDI. Any advice would be appreciated. Thank you.

Seems as though I’ve seen that when charging with an external charger.
You must be using a different charger, as the gem doesn’t have agm profiles.
And, no I don’t know why! :slight_smile:

Hi, we are using the same make and model charger which is the Delta Q 72V charger. The one we just installed to replace the GEM original Delta Q has the AGM profile available. There is one more difference in the charger programming though and that is with the interlock (green wire).

On the GEM when the charger is plugged into AC power it shows the charger charging on the cluster and activates the interlock feature by switching the 72V power away from the green wire, when unplugging the charger the charger then switches back so the green wire sees the 72 power at the batteries and disconnects the interlock feature. The charger we installed with the AGM profile has it programmed differently and does just the opposite. To compensate, we rigged the new charger green wire direct to the battery power so it sees power all the time and just does not interlock anymore. I can’t see this as being the problem though unless the interlock feature must be on when charging in order for the controller or BDI to be awake when charging.

Any further thoughts?


Gary Birke

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It may be the same model DQ, but Gem chargers have special sw. It prevents agm profiles from working.
Also the green interlock supplies power to the Gem start circuit unless ac power is applied.
As nothing else changed, that seem logical, needing the power cycle from green wire to reset SOC indicator.

It was the interlock wire causing the issue. We were able to add a toggle switch in line to break the circuit from the 72V which then allows both the interlock and BDI to see the charger plugged in. I guess the BDI and perhaps the controller have to be awake when charging. BDI functioning normal now. Just have to switch the toggle switch back to run (completing the circuit to 72V) when not charging. Thanks for all your help.

Hi: specifically, where can I reset the BDI on my 2006GEM? Just purchased and installed new batteries and it keeps showing the red signal (charge indicator)

you can do a full charge and it adjust