We have a lithium pack and an AC motor on our GEM. Went out to the parking lot to drive home after a meeting for a few hours and the car had no power when turning the key, and nothing when flopping the breaker.
Checked the BMS and saw the pack had shut off as the cells had disappeared.
Looked under the seat, and all appears normal and no damage.
Not sure what to do at this point other than to wait a bit and see if it comes back. Any ideas appreciated.
Which lithuim pack is this? Post a few pics. Look closely at the small red wires as they run around and especially as they gather into the white header plug and go into the bottom of the BMS. Do not unplug anything at this point.
Grab a meter and measure the battery posts directly.
Is this car in a good spot where it is right now? Or do you need to get it home? Depending on what you find on your batter posts, we might be able to jump the BMS to get the car to another spot.
Thank you for the fast reply @AssyRequired .
I believe it is a Samsung pack. It is showing 94v when I measure from the two posts on the lithium pack itself.
There were some leaves and dirt on top of the pack, but nothing seemed out of place.
Tried to take a few more shots of the label.
The NEV is in an okay spot, and it’s dark now. I would be okay leaving it here till morning if I needed to so I could look at it during the daylight
Battery looks full. I would bypass bms to drive home.
It should be safe to unplug balance leads and reinsert, but may be a pre/switch bms.
Needing 9v battery to reboot.
Thanks @lnwo for the reply and help.
It does have a small pushbutton on here, not sure if that does anything.
If it is better for me to leave it, I do have a car cover I can put on it.
I do not have the tools to disconnect the the battery on me so I would likely wait till morning to do that and come back with the right gear.
Unless there’s a way I can force the BMS on without a wrench
Now that I see it, go ahead and shut it down via long press on that button. (if you are still there)
Come back tomorrow with a couple of wrenches and we can instruct you on how to move a couple wires around and bypass the bms.
I’ll drive back over tonight and long press on that.
I assume to bypass the BMS I just want to connect the B- and B+ direct to my motor controller for the short hop home. Then can troubleshoot from the garage.
I wonder if emergency button would bypass that fault.
I long pressed the button and shut down the BMS tonight.
I was trying to lookup what the emergency mode actually does, as I didn’t want to cook anything.
I wonder if emergency button would bypass that fault.
Interesting thought. Might be worth a try. Depending on how wet this thing is internally, I’d hate for anything else to go poof on the way home and leave the car stranded in the middle of the road.
I assume to bypass the BMS I just want to connect the B- and B+ direct to my motor controller for the short hop home.
No, Much easier than that.
Right now, Your B- cable comes from the front of the car, back to the pack and attaches to the black legs coming out of your BMS. Detach/unhook this cable and take it to where your BMS Blue legs are going (to the stud on the front of the battery). You can remove the blue legs going to that stud. This takes the BMS out of the loop of control.
Do this with the Car Main Switch OFF. There is Voltage on that stud so be careful with the connections.
Thank you!
I was able to get the Nev back home where at least is easier to troubleshoot things.
Absolutely no issue once I connected the battery direct to the controller. It was a short less than 10 minute drive on flat surfaces as well so hopefully it didn’t put too much stress on balancing the cells.
I’m going to give everything a good cleaning to see if that helps, but I assume there’s a way for me to download the existing programming from the BMS to the app or at least screenshot it so that if I have to replace that, I can move the configuration over.
I haven’t opened up the BMS itself yet to see what I’m signing up for. I’m not sure if these are all individual leads that are soldered or if it’s a plug. Either way, I’m glad to know that the battery itself seems to be fine.
Yeah, Battery is fine. BMS is troubled.
You didn’t say how it got wet. Did you hit it with a hose recently?
Did it rain while you were inside at your meeting?
The Bal wires plug into the base of BMS. With the Blue legs disconnected, Inspect those. It the tiny wire pins are messed up, we’ll need to send you out a new harness to go between battery and BMS.
Remove the BMS to open it up to dry it out.
The two halves of the BMS case will butterfly open if you remove all of those little black screws. Find the 1 or 2 screws under the tape seal. Don’t worry about messing it up. (Consider it toast for now). Depending on what we see it might have a chance of resurrection. If caught when first wet, it would have better odds. If it soaked and sat around powered up for a while, things corrode quickly. (the nature of electrolysis).
No worries about the programming. we can set you up with what numbers will be good.
Now we need to prep another BMS and get it out to you.
Make sure you switch off the car via the MainSw while parked.
So the Battery/BMS was under a black vinyl cover, and it appeared to be overall dry, but there were some water spots that looks like wind blew in while I was inside. We had a rainstorm go through, but it wasn’t as crazy as what we will get sometimes where the rain is going sideways here in Central FL.
I have the disconnect off on the breaker for the NEV, and the cable from the P- terminal on the BMS is disconnected as well.
I will open up the BMS tonight and check if any water is obvious and see if I can tell anything is out of the ordinary/disconnected/broken.
It is in a climate controlled garage, which if something is wet, it should help dry it out. But to your point, the damage likely is already done if it was water.
So, she’s dead Jim.
I took off the cover and it didn’t seem like anything was corroded or cooked, but after putting it back together it is still showing the same issues.
Looks like I need to buy a new BMS.
@Inwo or @AssyRequired is this something you can help with? Or should I order from here
interesting. Do you have a meter?
Next we should check the pins in the header/collector.
Maybe it is something inside the battery case?
Pull the header off the BMS. Maybe tape the collector down so the backside showing the silver tabs is where you can get to them.
Be careful!!! This is tight work. There is no fuse involved here and a bunch of energy stored in this battery. If you somehow jump these pins, or cross your meter probes at this point it would be quite a flash.
Start with your reference leg. This is the black probe on your meter. Tuck in there somehow so it stays attached on the bolt where your blue leg from the BMS attaches at the battery pack.
Orient the header /collector removed from the BMS and identify the black wire. Call that Pin0. That is also B- and not needed yet.
The first red wire next to it will be Batt1. It should read one cell. (whatever state it is in) Looking back up at your posted screen shot you should see 4.06 between those two wires.
Then move down the line. Each pin should show an increase of 4v. (4, 8, 12, 16, etc…) If you are missing one, note which one that is.
When you run out of red wires/pins on this collector, Pull the other collector and it should continue increasing until it gets up to full pack at the last available wire at Pin22, skip 2 spots, then the last wire will also be full pack (88v).
Report back with what you find.
Your pack has 22 cells, that bms is for 20 cells
Hey @EOppegaard ,
Where did you go?
I second this,
I would suggest you use a single probe, (put the black lead of the voltmeter in the negative post of the battery and use only the red to measure the pins,
