Error 16, but Isn't?

07 E4, 96v lithium, -12v diode, AMD 7.5 motor. Showing about 87v remaining. Casually driving for 20~ min in DL yesterday and lost power. Flat road, no bumps or potholes. Coasted to a stop, turned the key off, back on and still no power. Flipped the main breaker off and back on, got power now showing error 16. Killed main power again for a minute or two, back on and no error, back in business. Ran another 10min or so without issue.

Looking up error 16:

Error code doesn’t seem to match the symptoms, considering I’d been driving it for 10-15min. Felt the controller and motor, didn’t seem overly warm. Any thoughts as to what caused the power loss?

Did the diodes overheat, is that even a thing? Seems like the controller was reading real battery voltage for a short time? 87v would be a 16 error.

Good question. I thought they just worked or failed?

Spoof only has effect at initial key-on. Over voltage while driving is fixed and senses capacitor volts.


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Any way to resolve? I’m guessing reprogram?

Next time the car goes dark, bring up your app and see what the BMS is reporting.
(this is ANT BMS)
Did the DISMos shut down?
Was V high for some reason?
Could be a short shut down the BMS? Shutting off the main power let it reset? (I thought you needed to manually turn FETs back on, but I could be wrong)

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Ah good idea, will do, didn’t think to check BMS. Still not fully used to it.

Also, a -12v spoof on a 96 pack sounds a little close. You might need to go -15v? You said it in your own statement:

Showing about 87v remaining.

I’m surprised you didn’t get a code 16 right away. You might be right on the edge. (I thought it was triggered on anything >86v).

Turn on key- measure V on B+ at controller(without MC kicked in) This is measuring the pre-charge through P1. Then let it sit there for a few minutes and feel spoof. Is it hot? Then measure V again. Same?/Higher?

Theory - Maybe the spoof is heating up and going a bit higher? The check for code 16 is at key on and it no longer looks to see what is there until next power cycle. A quick power down and back up again will find a hot diode and see higher V. Powering down like you did allowed it to cool and back into spec (pure speculation but I DID stay at a Holiday Inn a while back).

I agree 12v is too tight for 96v. Is it one diode or 2 in series? charger profile #161?

I this case my pack was reading 87, which controller would see 75. Sorry I should have specified.

Yes sir, this is your pack and charger. BMW 74ah with DQ on profile 161.
I’m using a single -12 diode.

ok that is good. My spoofs have 2 diodes soldered together(preferred way). I actually use a 6.2v and 7,2v diodes in series. when doing that the total voltage drop is less than the sum of the 2 diodes, don’t know why. But as stated don’t think it is your problem, if it was true high voltage it would only show, fully charged, at the beginning. My guess is controller going bad. I had one that would lose power and start throwing codes when I was driving, random. After 2 tows home I changed controller, problem solved,

So I’ve done quite a bit more testing on this. Looks like it’s the BMS doing it’s job.

I have the BMS “Low Cell Voltage Protect” setting at 3.1. Got a live screen capture under full acceleration on DL and DH. On DL, CellLow will drop to around 3.1 under full acceleration, then stabilize. In DH, it drops to 2.9ish and BMS shuts the party down. I tested again lowering the “low protect” and “low recover” settings to 2.950 and 3.050, respectively, and still got a shut down under full accel in DH.

Could this 7.5 motor be a little too hungry for my batteries to be able to put the hammer down in DH, or am I being too cautious with my low cell protect settings? Thoughts?

Around 00:03 is normal acceleration in DL, flip to DH at about 00:06, and full accel around 00:09. Shutdown right around 00:10 to 00:11.

No, cell protect is doing its job. Need more battery power or less amps.
I only see 200a pulling a single cell low. High cell looks fine.
Check balance leads and series connections.

need to see which cell is going low

Good call LG. What appeared to be cell 9 at first, quickly turned into the whole first pack after a quick drive around the block.

I think I need to run through every one of the settings on this BMS and make sure it’s 100% configured correctly. I didn’t have these sort of issues before installing the BMS…and when I DID install the BMS, all cells were within 0.01 of each other.
I did check all connections before re-charging and everything is secure.

lets try turning on balance. What is under voltage protection set at?

Auto balance seems to have been going all day intermittently. First was taken around 8 this am, second about 7:30 when I got home. Only cells 10-24 only ever turn green. Not sure what that means.

needs balance charge so they are all within a few hundredths of a volt from each other…

Voltage params:

Looks like you have a cell difference setting of 0.4V and as you can see in your green and blue displayed boxes they are all less than 0.4V difference. Me, I look for more than 0.05V for cell difference and when I see it I do a bit of cell balancing by putting my charger to take my cells up to 4.1V and the top balance circuits on each of my cells takes them down to 3.95V over night.

My setup is not the same as yours but the idea of cell difference voltage is the same. 0.4V is a wide variation for a lithium pack I would think. Let one of the Lithium guru’s chime in though since I’m no expert.