Got an error code 76… “capacitor voltage high electrical fault inspect motor controller”. What does that mean? It ran fine, then died at stop sign. Turned key off and back on again and it was fine. It’s an 02 e825 with 72v 100ah lifepo4 batteries on a jk BMS. Thanks so much in advance.
Chris
The BMS is set at 3.56 volts per cell for 100% SOC (state of charge). It was at 77.5 volts (24 cells) when this happened. Should I lower the 100% SOC to a lower number. What’s the max voltage that I can send through this capacitor? Thanks again
-76 → Capacitor (1C) voltage too high during pedal up regen braking.
This status code will be displayed when the voltage at 1C exceeds 96 volts during the regenerative braking cycle.
It sounds like something shut off the battery and the regen suddenly had nowhere to go, and power spiked high and set the -76.
Was this stop sign at the bottom of a really big downhill run?
Do you have Regen turned up high enough to generate heavy regen?
Assuming all your cells are balanced, 77.5v / 24 = 3.23v. I doubt a cell was tripping OVP. Your car would be dark as this would open/shut off the Dischage FETs.
Since you still had an active display, I’m guessing you tripped the Charge Current setting in the BMS. This would Open up the Charge FETs to protect the battery. Typically the setting is really low (~20a). If still low, Crank that up to 100 and see what it does. Then go take that hill again and see how much peak regen you are getting out of it.
If you look on your BMS App, in the upper right corner is a dot pull down menu. I there you can find status logs. Scroll through that and see if your error generated a line.
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Or perhaps this is not a battery issue at all. If your MC stuttered for any issue (loose connection?) this might have caused this overcharged Cap, Look for other signs of heat.
I had it floored to see how fast it would go and then pretty much braked hard to not run the stop sign. Just got the battery finished today and was pretty much treating it like it was a rental car. It’s mostly for an 87 year old that doesn’t have his license anymore. I wanted to max out everything while testing it out, figured ild much rather it break down on me than him while he is driving alone. I think you pretty much nailed it! It was it completely floored for 1/8 mile at 24 mph and then I pretty much slammed the brakes. The 2002 e825 have regeneration when braking? I had NO IDEA! Thanks for the info, I feel better, he’ll never drive it the way I was when I got the code. This thing will actually make the tires bark If I floor it on takeoff. The old man is SO EXCITED!!! THANKS AGAIN, I think your totally right! I can rest easier, and he drove it all around the neighborhood afteri got the code and didn’t have any problems at all. I am impressed with your knowledge, or you’re just frickin psychic! Have a great one .
Chris
Regen on the 00-04 is mediocre at best
Factory programming dumps most of the little regen it does as heat and not much back to the batteries.
The sensors and programming are different than the 05 → bodystyle change and ac drive
You spelled psycotic wrong. 
Byron is one of the best trobleshooters I’ve ever met. Maybe even the best
Not saying any of this is gospel, it was meant to suggest a bunch of things to look for.
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@JarJarJava
Regen on the 00-04 is mediocre at best
Since it sounds like this guy built his own battery pack I assumed he might have gotten into some controller programming too.
I should study up on how exactly regen works a bit more. I doubt it is triggered by the brake pedal switch. The wiring is not there for it.
I’m not sure if the controller is looking at the start switch on P3 (pedal up) in the accel pedal, or pedal position from the pot.
I wouldn’t expect stock controller programming on a normal flat road high speed run to trigger a BMS ChargeFet shutdown, but ya never know. It is worth looking at the ChgCurrent setting in the BMS. Neat thing about the JK is that you can see all this happening real time if you look.
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of the best troubleshooters I’ve ever met.
Most of the time I’m shooting from the hip. If you spray enough lead down range it looks awesome and every now and then something is tipped over when the smoke clears.