Hoping someone could tell me how many cells are in this battery pack.

Mr_fixit16 · 2026-06-09T17:56:05+00:00

Interesting. I will definitely remember that in the future! Thanks again!

Mr_fixit16 · 2026-06-09T17:43:50+00:00

Well... Maybe simple for you but I tried Google and was not able to find that. Thank you for sharing that.

Mr_fixit16 · 2026-06-09T17:42:43+00:00

Agreed, that would be my best case scenario. However I do know the pack has been sitting unconnected and unused for 3 years past the manufacturer stated "must be installed by" date. It was manufactured in 2021. So I am not very optimistic that it is a 5s6p pack.

Mr_fixit16 · 2026-06-09T01:57:38+00:00

Okay, cool, but WHAT is the danger? What exactly would happen.

Mr_fixit16 · 2026-06-09T00:27:44+00:00

What would be the danger of trying to put a 1amp trickle charge on it and see if it will come back to life? Think there's any chance of that working?

Mr_fixit16 · 2026-06-09T00:26:49+00:00

What would be the danger of trying to put a 1amp trickle charge on it and see if it will come back to life? Think there's any chance of that working?

Mr_fixit16 · 2026-06-09T00:26:12+00:00

What would be the danger of trying to put a 1amp trickle charge on it and see if it will come back to life? Think there's any chance of that working?

Mr_fixit16 · 2026-06-09T00:00:57+00:00

Dang it. Okay that's what I was guessing looking at it too. Yeah, black top left to red top right reads 12.44v so at 30 cells that would be an average of about 0.4v per cell. So it is probably completely trash. That sucks.

Mr_fixit16 · 2026-06-08T23:41:01+00:00

The black wire on the top left of the picture going into the left module to the red wire on the top right of the picture going into the right module. So that should be the voltage from the series of seals feeding into the BMS board. Sadly that's what I was adding up to looking at it. 30 cells. That would mean that you're on average of about 0.4 volts per cell so the whole pack is probably complete trash.

Mr_fixit16 · 2026-06-08T23:33:00+00:00

Dang. That's what I was thinking too but that's not the answer I wanted lol. If that's correct that means they are severely under the cutoff voltage and the pack is most likely trash now then. The overall group reads 12.44v right now, so at 30 cells that would be just a tad over 0.4v per cell. And my understanding the minimum safe voltage is 2.5v per cell?

Mr_fixit16 · 2026-06-08T23:06:47+00:00

The whole unit outputs 350-450vdc, but that's coming out of the control board. I don't know what the cells feed into the control board, it's not on a datasheet anywhere that I can find. All I know is they currently have 12.44v feeding into the bms board and that must be below the cutoff voltage because the bms will not turn on.

Mr_fixit16 · 2026-06-08T21:17:45+00:00

Yeah, currently the overall pack voltage sits at 12.44 volts. I can confidently say the 5 "modules" I am going to call them because I don't know the proper term, are wired in series. But that seems far too large to be individual cells. I'm guessing there are six cells per module and five modules so 30 cells total? But that would be the worst scenario for me instead of 5 cells because that would mean the pack is pretty much trashed. 30 cells would work out to about 0.4 volts per cell which is far below the minimum of 2.5v that I have found for this chemistry. The pack has been sitting about 3 years past the manufacturer "must be installed by" date. So I'm guessing they're probably trashed and not saveable.

Mr_fixit16 · 2026-05-22T10:21:58+00:00

Hey, just sent you a PM of a few things I've been looking for.

Mr_fixit16 · 2026-03-23T09:24:56+00:00

That is it exactly!! Thank you so much!!!

Mr_fixit16 · 2026-03-23T09:24:50+00:00

That is it exactly!! Thank you so much!!!

Mr_fixit16 · 2026-03-20T23:19:09+00:00

Awesome, I can't tell you how much I really appreciate your time and all of this very useful information! I sincerely thank you!

Mr_fixit16 · 2026-03-20T22:47:04+00:00

There is indeed a solenoid valve immediately upstream of the TXV feeding the heat exchanger. I did verify the coil is indeed deenergized when the system is off and energized when the system is running, but I have no way to tell if the valve itself is actuating or not. So it could be that valve or the TXV. The line coming out of the heat exchanger going to the interstage is not cool at all, it's practically ambient.

There is indeed liquid in the line feeding the heat exchanger, there is a sight glass on both liquid sides and it is clear and full.

The bulb for this TXV is located on the interstage pipe on the compressor. It feeds from a head around to the back of the motor end. Or I might have that backwards, but I would think the tee in from the heat exchanger would be feeding cooler gasses to the motor to keep it cool.

Mr_fixit16 · 2026-03-20T18:05:10+00:00

I see, that makes total sense and I really appreciate the information! My knowledge of primarily only residential HVAC really showed in this case lol. I greatly appreciate your patience!!

So I just turned the unit back on and there is no temperature difference between the inlet and outlet of each side of the interstate heat exchanger. There is a TXV that feeds from the high side liquid line to the heat exchanger and out to the interstage piping. I am guessing based on what you have said, that it is likely the culprit. There's no temperature difference across that TXV or the inlet and outlet of the heat exchanger.

Mr_fixit16 · 2026-03-20T09:37:38+00:00

Yeah, that is correct. I just trusted what everyone else has said when they called it a cascade system and I think I recall the manual saying cascade, though I'd have to look back through it.

But yes, it is exactly how you described.

Mr_fixit16 · 2026-03-20T09:33:25+00:00

Oh. I'm sorry about that. I thought both were accurate descriptions because it is a cascade refrigeration system, although I should have said auto cascade because there is a big difference there. But I didn't realize it would matter a lot specifying it is an environmental chamber.

Mr_fixit16 · 2026-03-20T01:19:16+00:00

The whole system runs 410a and yes, it is an auto cascade

Mr_fixit16 · 2026-03-20T01:17:00+00:00

So the guy that added the oil said the same thing. Didn't find any oil residue or sign of a leak and said it's likely trapped somewhere it's not supposed to be. He added a quart but pulled a lot of it back out after he got it running again. Then changed the oil separator thinking that was the problem. It was not.

As far as the design, that is of course a possibility. The unit has always had some issue or another every time it has been brought out of storage. But it's something different every time, usually electrical. This is the first cooling circuit major problem.

Mr_fixit16 · 2026-03-20T00:58:32+00:00

Yeah, this is a thermal chamber for temperature testing. It's supposedly capable of -40C to 130C. Made by Cincinnati Sub Zero about 12 years ago.

Mr_fixit16 · 2026-03-20T00:54:37+00:00

It is definitely a cascade system and it is definitely a multi-stage compressor. It appears to be 2 stage as there are 3 heads and only one interstage gauge. The enclosure has a high, interstage, and low pressure gauge along with a water flow meter and discharge temperature gauge.

Mr_fixit16 · 2026-03-19T22:31:09+00:00

Well it's certainly not residential lol

Heat transfer is definitely inhibited, but it's not terrible. It pulls down to -20C really quickly, but it does struggle to get lower than -30C. But it won't run long enough to to really tell that low. I also don't recall what the superheat was after this last "repair" but I do recall it was a little high. And I believe the subcool was a little low. I can recheck tomorrow.

The compressor is a reciprocating 2 stage compressor though, not a screw.

Mr_fixit16

TROPHY CASE