Same old problem after much troubleshooting

2008 e4 loses power after about 1 mile. Total miles less than 6000. Only about 2000 since new batts in 2019. No error code displayed, but suddenly slows down to less than turtle speed and after a few minutes will just stop. I’ll turn key off and wait a minute, then limp it on home. Delta Q charger profile 14 checks out and works fine. 2019 new Deka gel batts 8G-31 have all been individually load tested with 25 amp draw for 190 minutes, checked out fine and show maybe 10% loss, typical for their age. Controller was sent to Ride-4-Fun to be bench tested and checks out fine. Any ideas? I’ve been struggling with this situation for a few years now. Frustrated!

What’s the voltage going into the controller from the batteries when it dies?

Thanks, David. Let me get back to you on that. It didn’t occur to me to check full charge voltage vs after.


Did you do the battery testing? Or did you have it done?
When was this done?

Do you have a meter to test it yourself?

Yes- as David suggested- sending us some numbers will help to figure this out. Otherwise we are all just guessing.

If you can tie your meter leads to your controller posts and monitor things when you are driving around that would be even more helpful. With special attention paid at point of failing.

If you see a big voltage drop at the controller do the same test across the connections of the main contactor. A good contactor will show no volts across when driving.

What is your SOC meter saying during all this?
After a good romp around the block have a feel of all the big amp connections for a warm/bad one. Make sure all are shiny, bright, and clean.

What else have you done/tried in the last two years of dealing with this same issue?
I see that back in March you had a -45 error. Since it appears you sent your controller off I’m guessing you assumed it was the fault. Is there another thread associated with this that I am missing?

Did you ever get a look at the brushes and look for brush arc? When was the motor last serviced?

Check for dragging brakes. Do a "brake load test " on the batteries.

Thanks to all for suggestions. After a full charge I took a volt meter and note pad for several hours over the last 2 days. Voltage reading, in order:
73v+ to start, then 2+ miles, suddenly drops speed, meter goes to 1 red bar, no error code, reads 71v+. Sit with key off for 30sec. Drive off with full power but meter only shows 1 red bar. Again sudden drop in power so I stop. 68v+. Sit with key off, then take off, no full power but I drive it for 2+ miles. Suddenly stops and now error code -45 and turtle mode icon shows up on dash. Again, 68v+.
Limp it home, sits overnight, reading this morning is 71.3v with 1 red bar showing.
To test for motor brush arcing do I simply jack up front end, accelerate and observe the motor?
So confusing this 2018 e4.

Meant to say 2008 e4

So you have 6 fully charged lead type batteries and ONLY 73V to start? Simple math( 73/6=12.2V) means your batteries are over 50% discharged… A fully charged lead battery will usually sit at 12.7Vea for 76.2V fully charged.

68V is 11.3V each and you are likely damaging the chemistry by running them that depleted.

Did you do this?..
Need batteries!

Thanks, INWO. I’ll do it. This time with leads to the dash right into the voltmeter. I’ll report back.

Thank you,


Yes, needs to be under load. Any drop to 68v will trigger turtle.
Might just be one bad. Or connection.

Aug '20 - BRAKE LOAD TEST Put your volt meter on 1 battery, hold your foot on the brake HARD and push the throttle for 2 seconds and note the voltage. Do all 6 batteries. The dud will show up. Rodney

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Will do. Thanks, Rodney.


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Everything checks out. Never drops below 76, even when sudden slow down and turtle mode. Car will then actually stop when in turtle mode and I have to turn key of for 30 sec to be able to start back up. Again, never drops below 76.

Still trying to figure out what’s wrong. Also did a brake load test on each individual battery. All check out fine.

Brake load test checks out all good

The only thing I haven’t tested is for motor brush arc. Do I simple jack up front ens, press pedal and look for signs of arcing at the motor??

Motor service $100 labor. Machining and parts at cost if required. Check my reputation.


tested is for motor brush arc. Do I simple jack up front ens, press pedal and look for signs of arcing at the motor??

Yes, that is exactly what you do. Where to look depends on what motor you have. Certain motors may not have clear visual access to the brushes and you may not see blue flash so you will need to listen. Some motors have a solid band clamp that will help if removed. Some motors have stamped holes you can see through. It may also help if you drag the brake when stomping on the accel. Having an assistant to do this will help.

Brake load test checks out all good

Tip: If you want further help, you will have to do better than this. You currently have an audience of some of the smartest people on the planet (and me) and thousands of hours of actual hands-on experience. Using the words “checks out all good” just brushes off the current line of questions and assumes you know more than everybody here. That contradicts why you are here asking for help with you non functional car.

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