Failure despite near complete 2005 E4 rebuild

Issue Background: The car is a 2005 GEM car, running primarily on gravel roads. It has lately been suddenly decreasing speed while driving to the point where the maximum speed is sometimes as low as 1 mph with the accelerator fully depressed ( low, high, and reverse all the perform the same).

What has been tried/replaced so far:

  1.   All batteries replaced with new gel batteries.  Result:  The Issue remained
    
  2.   Motor replaced ( it did look a burnt up inside).  Result:  Issue remained
    
  3.   Controller replaced.  Result:  Issue remained
    

After the repairs above were done the issue appeared resolved only to have the issue happen again within a day or 2.

What we know:

  1.   The battery voltages are above 72V and the car shows fully charged on the display when the issue happens.   
    

2… There are no error displayed on the screen.
3. The Contactor measurements were per the manual and though I could not measure all the PSDM points ( didn’t get to the printed circuit board) I checked most of the PSDM lines and the voltage measurements matched the master manual. No fuses are blown.
4. There is an error at the end of the charging cycle that is occurring. There is a 2 blink error on the red LED of the DeltaQ onboard charger that happens. This seems to happen when the batteries are nearly fully charged and not when they are drained.
5. During troubleshooting it seemed like the accelerator resistance was not measuring at all, this could have been an issue with making good contact not sure.

The one odd thing is the performance can be restored for a while by switching the master switch to off and letting it sit for an hour or so to drain off the charge and then switching the master switch back on.

Was wondering if anyone has seen anything like this failure before and/or have any idea’s where the issue might be. Could the charger issue be somehow causing this? Would an accelerator fail like this?

How old are the batteries? What type? A very high percentage of problems w/ GEMs are battery related.

Al

[quote=ARandall;25357]How old are the batteries? What type? A very high percentage of problems w/ GEMs are battery related.

Al[/quote] The gel batteries are brand new–as noted in my write up, I just put in brand new batteries, brand new motor, and brand new controller.

Say these are “new GEL batteries” covers a LOT of territory! Size/brand? Is charger set for GEL?

Al

[quote=ARandall;25361]Say these are “new GEL batteries” covers a LOT of territory! Size/brand? Is charger set for GEL?

Al[/quote] Deka Dominator Gels 8g31, newly installed by Marc of Hollistor Powersports in first attempt to repair this problem. Next attempt was the new motor (and I also opted for the new controller as I am a long way away from repair service). These replaced my 2009 installed Gels, and had normal use/power for a week or so (probably less than 30 miles of use), then the same the problem re-appeared.

Charger maybe? Sounds like you’ve covered all the other bases pretty well. The fact it resolved for a short while and then started acting up again seems suspicious to me. Maybe charger isn’t charging the batteries completely? Can you get a voltage reading once it starts misbehaving? Can you verify that the charger is set correctly for GELs?

We measured the voltage of the batteries when the failure was occurring and it was 78v and at that time the max speed of the vehicle was 1 mph. Since I had gels in there since 2009 and everything was good till this failure (which came before the new gel batteries were installed as the first fix), I am presuming that the charger was set right for gels–and it probably is. Is there an easy way to tell?

Hmm, Sounds about right for new gels and full charge and yet it still wouldn’t go. Puzzling to say the least. I imagine it’s safe to assume charger was programmed for GELs since they were the previous technology and worked correctly (until they didn’t).

I’m wondering if there is a connector or bad connection somewhere in the primary side of the circuit that has too much resistance to let the motor draw sufficient amps once it gets going. The cart can draw up to several hundred amps and if the battery pack is up-to-snuff it should go!

I don’t know enough about the DC motor used in GEMs but I guess it’s possible the field current side is another area to investigate. Maybe someone that understands the technology used in these DC motors can chime in. I’m pretty much out of ideas to chase.

Sorry, good luck. Will be interested to know what finally solves your problem. I’m sure it’s frustrating. You might want to contact either Marlon or Ride-4-fun for their suggestions. Both of them really know GEMs.

Al

Although it seems unlikely, new batteries from the factory can be bad. The double red light blinking means the charger never got its chance to fully charge the batteries. Just one cell in all of the batteries can cause this problem. All the batteries may show a full charge but as soon as you put a load on them one may show its problem. Does the red turtle on the dash show up after awhile? This could be the detection of a bad battery. Be suspect of the battery that has the lowest charge after charging. Even if it’s only 1 tenth off.
Barry🚄

1 Like

Barry makes a good point. We all use voltage as an indicator of battery health but a better way to check is to use a load test to verify that all the new batteries are healthy. Any auto shop or battery dealer should be able to help with this test. I’d run the test after experiencing the problem. You might find one battery is simply “weak”.

Al

Did you check for a stuck wheel cylinder. Brakes heating up can slow you down and stop you.

[quote=ARandall;25382]Barry makes a good point. We all use voltage as an indicator of battery health but a better way to check is to use a load test to verify that all the new batteries are healthy. Any auto shop or battery dealer should be able to help with this test. I’d run the test after experiencing the problem. You might find one battery is simply “weak”.

Al[/quote]

Well, I would tend to agree, except this continuing problem started before I replaced with new batteries, remains identical to the problem, and the problem continued. And, different from the 2009 battery replacement, I have never had a turtle icon show up (even when power drops to 1 mph), while in 2009 I was able to “turtle along” for awhile, charging more frequently, before ultimately replacing the batteries way back then… It behaves differently–no change at all in acceleration when fully depressing the accelerator pedal once the lost power problem appears, and with the dying batteries in 2009 I was able to have a different speed with different level of pedal depression.