Thanks. I will give this a shot next week. I fixed my Dad's old Black Knight pinball machine and had to deal with a lot of solder work on the analog copper wiring for the bumpers and such, so it will not be too unfamiliar to me.

Well . . . I was afraid of this when I took the photo yesterday. Sorry I missed the tear originally.

Now, the internet is full of advice for what I can do at this point in time, but I always prefer the thoughts from this group of learned folks.

1. Fix the connection. How realistic is this at the ...

I am using one of the new Felten branded BMS swap cards like the one in your photo. I had 14 of them, so I did try more than one on this 5S battery to make sure the readings were not from a faulty BMS swap card.

I will use your numbers above to check out the readings on the plates today and report ...

Thanks muehlpower. I will head back to the shop today or tomorrow and do some more investigating with the ribbon cable and retake the voltages to make sure that the top left in the second set of voltages was actually 0. Is it telling that in my "plate to plate" measurements, I never got a reading of ...

OK. So I went to the shop and followed muehlpower's instructions. On the 5 cell battery, here is how it came out:


Untitled spreadsheet - Sheet1 (1).jpg


There was never a 3.15v option, but two 9.48v readings side by side. I am not sure if this was expected or means something is wrong.

When I ...

Hi muehlpower. Thank you for this detailed explanation of how to take the voltages. I will plan to do this tomorrow when I have time. I watched a video over the weekend about taking the voltages directly from the PLATES with the battery on its side with red cable on the top plates and the black ...

Thanks for the additional posts.

Do you have HV fuses or other disconnect devices between your battery boxes?

Yes, but nothing in the middle of any cell groups. I have one box of 6 batteries (36 cells) which passes through a FUSE on its way to the next box with 6 batteries (36 cells) which then ...

Finally, use a multimeter, as you have been advised to do here several times, and measure the voltage between each two cables to find the correct order


I appreciate the response and I have no objection to using my multimeter, but up until this week, I have not had access to the entire module to ...

In Tesla modules, the BMS control wires often fall off


Do you think this is why I am getting the strange readings on Cell 1 and Cell 2?

Do I need to take a multimeter reading on all 340 active cells and see if they all land in the same range to confirm that this is a wiring or programming ...

Thanks again guys. That makes me feel better.

Now, my other question. The readings on the 13 batteries without any dummies came out as follows:

Battery 1
3.132
3.141
3.134
3.156
3.136
3.148 18.847
Battery 2
3.139
3.158
3.146
3.167
3.143
3.159 18.912
Battery 3
3.126
3 ...

As I discuss in another post, I am having to swap out my 14 Tesla Model S modules and aquired a complete TESLA MODEL S / X LITHIUM ION HV BATTERY PACK 75kWh 350VDC. I took all of the modules out of the case and swapped out the BMS cards and took voltage reading on my BatteryGO device.

When I was ...

I agree Tom. Its a mess! I am getting a new ORION 2 from Chris Hazel, since he will be in Nashville next week and we can meet up. While the car is open and all of the battery boxes are removed, I will run the new harnesses to the battery boxes and start over on all of this. Once all of the batteries ...

I pulled out the cell taps from the ORION 2 and inserted them one at a time to take readings. Here is what I got. Unfortunately, I started popping fuses like popcorn when I got to the last one so I shut it all down and emailed Andrew Ewert again. Oh well . . .

Hi Tom. Thanks for the reply. When you say test it with the multi-meter, I want to understand where I am testing it at. The BatteryGO was connected right at the battery mpdule without using any of my wire taps. I previously tested at each of the latge boxes at the HV +- inlets to each box with the ...

I pulled out the driver's seat and took the BatteryGO reading on that one and this is what is says:

image.png

Once again, these are much higher than what the BMS was telling me and they do no match up with any of the numbers showing on the ORION readouts. I wonder if all of my other battery ...

Hello again. As an update on my situation, I am getting the car ready to be towed to the shop for the battery swap out using the recently acquired 14 modules. In prepping the car, I removed the passenger seat to expose one of the batteries. Since I can easily access this one, I used my old BatteryGO ...

I am looking at these params and I am just flummoxed. The one that Johan sent through must have been before these were uploaded and his are how I always had it, so this one is totally whack and makes me wonder if I uploaded the wrong file at some point, but I am kicking myself pretty hard.

"udcmin ...

Once again, thanks fellas.

As to the 170V, the voltage keeps jumping around and settled back at 200V at some point after I took these screenshots, but yes the HV was open when I took these screenshots. Again, the front box of 6 batteries is giving me 101V (now 95) and the rear box of 6 batteries is ...

Thanks guys. This weekend I am going to take the seats out of my car, since 2 of the tesla modules are under those seats and NOT in the larger boxes that hold the other 12 batteries which will require a full tear down to access. Once I can access those 2 batteries, I have an old BatteryGO tool I ...

Hi. SO . . . I pulled the trigger on a new set of 14 modules, since I got them all together in one pack of 14 and the price was right. I was able to visually inspect them in person and they appear to be in good condition and they all have voltage at or above 30V.

When I get the new batteries into ...

Now I just have to remember what is different in the ORION 1 to get that hooked back up! LOL

It has the same battery cell connectors and power, but a different thermistor plug, which I guess I do not need for this experiment, but I think it had a voltage tap piece I would need to reconnect. If ...

Apologies for leaving that out Tom. Yes, I unplugged the entire box and left it overnight and plugged it back in this morning. The result was the same types of readings, with SOC at 230% and then 5% and then 12% and cell readings all over the place.

Thanks Tom. I bought it directly from EWERT and I am in an email exchange with Andrew Ewert and he believes the batteries are the problem and not his BMS. I have no way to know and he has not addressed the wacky readings. All I know is that voltage for each box (6 batteries reading 100V and 6 ...

When I power cycled the front battery box, the ORION readings went nutty. SOC went to 50% and then to 30% and then 5% and then settled on 10.5% and pack voltage went up to 200V and the individual cells changed again. I have not done any charging, but they went up. I am about to jettison 20k worth of ...

I took the multimeter to the front batter box (36 cells) and it also read out as 101.4.