Im losing my mind!!

[gmehal]

Help im losing my mind. I started this project months ago and have had limited success. Months ago after watching a few of Wills videos I decided to pickup 8 190ah cells from ali express to build a 24v system. Months later they arrived and the build began. I have 2 Dali BMS's, one an 8s and another 4s, I also have a 21s BMS that Will feateured one of his videos. In addition to that I have a Electrodacus SBMS0.

To date the ONLY configuration i can get to reliably work is the 4s 12v system! Every time I hook up the other 4 cells to make the 8s 24v system the BMS's I have wont charge it and the Giandel 24v inverter dosen't work either! Stupidly frustrating. No matter what 8s BMS I use and I have 3 it just wont work. Im hoping that someone can see something obvious I missed.

Hardware list
4, 100w solar panels
Victron 150/35 SCC (set to 24v)
8, 190AH Lifepo4 cells from ali express, all verified at 3.3v per cell 26v for pack
Victron 200A battery protect (set to 24v)
Dali 8s 100a BMS, Ebay 21s BMS, ElectroDacus SBMS0, Dali 4s BMS
Renogy 1000w 12v inverter, Giandel 24v 2000w inverter




THIS INVERTER IMAGE ABOVE SHOWS 26.5V, SORRY THE DISPLAY FLICKERS

THIS IMAGE BELOW SHOWS MY POWER STRIP CONNECTER TO THE 24V INVERTER, IM NOT SURE WHAT THESE SYMBOLS MEAN BUT I THINK ONE IS GROUND? NO POWER AT POWER STRIP

 

[MisterSandals]

Based on what your klein dmm says and what your victron app says, you may have your 8s loom hooked up incorrectly.
With you dmm, test the loom connector.
Put the negative probe in the 1st hole and positive probe in the second.
Does it read about 3.2v?
If so, move positive probe to next hole. Did voltage increase by about 3.2 (reading about 6.4)?
Do this for all holes. If you find a discrepancy from the 3.2v increase, you found the wire in the wrong place.

 

[gmehal]

Great idea, will test now

 

[gmehal]

Ok did the above test and all looks well. Voltage increases pin to pin by 3.3.

What else? Any more thoughts? Like I said whe I hook this up in a 4s config it works great. Im so baffled

 

[KauaiMolokai]

Is the photo of your Inverter reading 2V input?

Are you able to connect the Inverter to your 8s battery, without anything (BMS, etc) connected to the battery?

 

[gmehal]

Did you read the caption under the photo?

The display refresh rate wont allow me to capture it with phone. Its 26.5v. With or without BMS its the same problem. Remember I have tried 3 separate BMS's

 

[gmehal]

Here is what the 3 LED lights indicate on the power strip Red, Green and Yellow. This is connected straight to the inverter, again in the 4s config this works without issue

 

[onemorebattery]

Put aside the BMS issue for a second. Connect your inverter straight to the 24v battery and verify that the inverter/battery combination works. Does it work? If yes then take a moment of joy then go back to the BMS issue.

 

[KauaiMolokai]

Did you read the caption under the photo?

The display refresh rate wont allow me to capture it with phone. Its 26.5v. With or without BMS its the same problem. Remember I have tried 3 separate BMS's

You get a lot more help from people on here (and in life) if you're calm and polite.
No, I missed reading about your photo/refresh rate issue. My bad.

The next poster is suggesting you do exactly what I asked you if you could do. But which you did not even answer.

We have all had "i'm going out of my mind" problems. A fresh set of eyes helps. But don't bite the hand that feeds you for free!

 

[gmehal]

Calm and polite? what are you talking about? I was just asking if you read the post above, chill. Anyways getting back to it, yes I have tried just inverter direct to batteries numerous times, here are photos for proof. I just cant understand why the output to the inverter is wacky and the BMS going in is also wacky just in the 8s config. The inverter image shows the input, it cycles between that and the output being 0. It took me 14 photos to catch that flickering readout lol

 

[KauaiMolokai]

OK, all I can suggest is what I would do. And forgive me for a few questions I ask because I'm not familiar with your equipment. Yeah, its an interesting problem for sure.

So, first question. Let's forget the BMS for now and leave it disconnected.

Is your inverter capable of accepting some range of different input voltages (say 12V, 15V, 18V, 20V, etc) and still producing 120VAC output?

If so, I would connect the battery to the inverter and use a different number of cells until you get that flickering input number to be steady. In fact this test might work even if your inverter doesn't produce 120VAC with less than 24VDC input but still reads input steady.

My theory is that you might have a bad cell.

Have you tried connecting different cells to make up your 4s battery (which works fine)?

 

[MisterSandals]

There is a lot going on that is unexplained. Why are you using a power strip? And that looks an awful lot like an uninterruptible power supply, but I can only guess.
Can you just plug a lamp into your inverter to see if that works?

 

[gmehal]

Ok its just a power strip not a UPS, I tried another power strip and got the same results. I have a line from the inverter to a dedicated wall outlet in my home. Currently I use solar and the battery bank to charge anything battery powered in my home, thats a lot of stuff, hence the power strip lol.

I measured the AC voltage coming out of inverter, not 120v AC. I will check to see if it can accept a 12v input but since i have a 12v inverter as well i have just been switching back to that when i do the 4s config. I have tried using each of the 4 cells as a separate 4s unit and they work fine seperatly.

As for a bad cell what would be the signs? All checked out when I first received them, all were 3.3 nominal.

 

[KauaiMolokai]

Suggestions:
Check the available AC voltage from the inverter without having that yellow plug or anything else but the voltmeter plugged in.
Also check the available AC voltage from you 12V inverter, also with no loads, nothing plugged into its outlets.

Yeah, thanks for the photo - your 24V inverter certainly shows 24V input. I wouldn't bother hooking up less than 24V worth of battery to that.

 

[gmehal]

same result with no load. Seems like the 8s config is the issue, BMS has issues with charging on the input and the output makes the inverter weird

 

[gmehal]

Here are some specs from Amazon on the inverter. I get none of these warnings that they show in the photo, Just Fyi

 

[KauaiMolokai]

OK, so your 24V inverter is not putting out 120VAC.

Either the inverter is bad or the input to the inverter is inadequate.

Can you get 2 sets of 4s cells fully charged by using the 12V system you says works well, first on one string of 4s, then on a second string of 4s, so that you KNOW you are starting with good, fully charged cells?

Then hook up the 2 4s strings in series again so you should have 24V of good, fully charged cells. Then connect this 8s string to the 24V inverter and check the output again, unloaded. If its not 120VAC then the inverter is not right.

Did you check the AC available from the 12V inverter?

Again, for now disconnect and forget the BMS on the 24V system. Use it only on the 12V system since it works fine to charge your cells in that 4s config.

 

[gmehal]

OK, so your 24V inverter is not putting out 120VAC.

Either the inverter is bad or the input to the inverter is inadequate.

Can you get 2 sets of 4s cells fully charged by using the 12V system you says works well, first on one string of 4s, then on a second string of 4s, so that you KNOW you are starting with good, fully charged cells?

Then hook up the 2 4s strings in series again so you should have 24V of good, fully charged cells. Then connect this 8s string to the 24V inverter and check the output again, unloaded. If its not 120VAC then the inverter is not right.

Did you check the AC available from the 12V inverter?

Again, for now disconnect and forget the BMS on the 24V system. Use it only on the 12V system since it works fine to charge your cells in that 4s config.

Yes i have been successful with 2 sets of 4s. I will try this again because I can.

Yes to AC, see post above

Will report back on the 2, 4s config voltages

 

[gmehal]

So after stepping down to the 12v 4s system it works like you'd expect. Man what is it with the 8s config

 

[KauaiMolokai]

Cool. So it looks like that set of 4s cells works well. What is the available VAC from that inverter with no load?

 

[MisterSandals]

Did you happen to check the power coming into 24v inverter when it was putting out 98v?

Its looking like a bad 24v inverter if 24v are going in.

 

[MisterSandals]

Nice work Kauai, you are giving the royal treatment to gmehal!

 

[gmehal]

120v AC, charging a few things now. Basically works the way an inverter should

 

[gmehal]

Did you happen to check the power coming into 24v inverter when it was putting out 98v?

Its looking like a bad 24v inverter if 24v are going in.

I dont think its the inverter, reason being is that the BMS wont charge the cells in 8s config. Something is up with the 8 cells together only.

 

[KauaiMolokai]

Awesome! Now if your 12V system works and checks out exactly the same with the other cells in a 4s config we can be pretty sure you have good cells.

I've chased various things (not solar) for months, and its usually a good idea to go as far back to the basics as possible so you know for sure what you have. Either that or, like my Priuses, just throw parts at them until something improves ;-)

Thanks Mister S, I appreciate your kind words.