Gem car won't get to full speed

My gem car won’t get to full speed it is maxed out at about 13- 15 mph. I can come to a complete stop and start again and sometimes it will get up to about 23 and then lower back down while I still have the throttle all the way depressed. It is not showing any error code

Make sure your not in turf mode.

Monitor the battery voltage when the problem occurs and see if it is dropping too low. As mentioned, make sure that the HI/LOW./REV switch is working properly.

Did you ever find a solution? I have the same problem…

That would happen to me and then I’d get the turtle. Would top off batteries (lead acid) and perform individual charges to get them up to 12v and then put on 72v charger over night. Would usually cure it but eventually, I had to replace the batteries as they were 5 years old.

I have a 2010 GEM e2. Discovered I had a loose connection on my A2 output terminal on the controller which caused the post to overheat and melted the cover around the post. I cleaned everything up and reconnected the terminal. Everything went well except that the top speed, which I assumed was controlled by the governor, would only reach around 17 mph. Prior to the loose connection event, the car went to full 25 mph. I assumed that the controller was faulty and had it rebuilt. I reinstalled the rebuilt controller and no results. The car will still only do 17 mph. I heard that there is a circuit in the gas pedal signal to the controller but I don’t know how that works. The batteries are fully charged. Any comments or suggestions on what might be the problem?

Do you have a handheld Multi meter?
As the per the suggestion above^^^

What is the voltage going into your controller at rest?
Then when driving around at full speed?

What is the condition of your battery pack?
How old are they?
When was the last time you checked the balance?
When was the last time you added water? (If wet cell)
How do they work under a load test?
Are ALL of your connections clean and tight?

Also- When was the last time you had your motor serviced?

It also could be a dragging brake or tires not properly inflated.

Did you have a headwind that day? The guys on the salt lake speed runs turn around and go the other direction before they qualify for an actual speed record.

So yeah, there are alot of things that it could be, but sure it could also be a pedal issue.

Possible problems that don’t set error codes 2005 up

1 Bad armature car will run up to 1/2 speed AMD 7.5 GE 7 GE 5 LONG

2 Bad Throttle assembly usually plus 4000 miles

3 Corrupt programming

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Thanks for getting back to me AR. I didn’t get any notifications and didn’t realize there were responses. Yes, I have a multi meter. I have new lithium batteries which have worked well the past year. Voltage at rest depends on level of charge but normally starts between 75 and 80 volts. When driving at full speed it drops slightly in the 72 volt range. All electrical was well before the loose connection. I have since had the controller looked at a second time and it performs to OEM specifications. So there is an other electronic device which is limiting the top speed. It has great torque and acceleration but puts on the brakes (feels like the governor) around 17 mph. The hi/low and reverse switch works fine. I understand there is a potentiometer in the gas pedal circuit. Could this cause the problem?

Switch or switches? Shoujld be a HI/Low switch which limits your top speed to around 15MPH in Low mode and ~2x that in Hi mode. Then there is the Fwd/N/Rev switch which handles direction of travel.

Is turtle on?
Dipping momentarily sets turtle until next charge cycle.
Original charger? Needed to reset turtle. What battery? 80v seems on the low side, but ok.
Measure wot on p7. Should reach 3.0v for 100% throttle.

Reading back, i see you have a bunch of small lfp in parallel.
I dont know anyway to test them, other than possibly one at a time.
Reconnecting after they are all on and balanced.
Or test drive with a known good battery
We have seen limited performace with similar batteries. Even though they seemed to hold voltage drop to a resonable level, top speed was not there.
Last time, Gabe flew out to help, and we had to swap batteries to get full performance.
In fairness, they were series connected, but sounds all too familiar.

Bad armature is a possibility, Also bad pedal. borrow a motor to check. If pedal it will get worse in a hurry

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Yes, switches. In the lo position it only goes 8 mph.

The turtle has been on ever since I replaced the batteries with lithium. The charge display has also been at one red bar the same amount of time. That’s why I installed a separate battery monitor assuming that the display was not compatible with the lithium batteries.

Can you explain wot on pg7? And also 3V at 100% full throttle?

P7 of controller is the signal from the throttle. Full throttle is 3 volts.
Not the issue, as i see you disconnected the oem charger.
That will keep car in turtle mode.
I’m having a hard time feeling your pain, after you ignored our advice and went your own way.
We do 100s of conversions and know how to make our batteries work in Gem cars.
Byron has a better attitude and will get it ironed out eventually. :slight_smile:

The lithium batteries have worked fine for the past year so it is not a battery issue. It wasn’t until the loose connection on the controller was repaired that the low speed occurred. I assumed it was the controller but I had it rebuilt to factory specs and at full speed in the high switch position still only goes to 15 mph. It definitely feels like the governor kicks in and holds it back.

I guess I misunderstood. Changing the charger has not caused you any grief!

I’m not understanding. What advice did I ignore? I have appreciated all of your help. Thank you.