Should I Send My Battery for Warranty Service? Don't Want to Be without Electricity!

[AgroVenturesPeru]

We're living off grid in a remote part of Peru, and one of our four batteries has been acting up. Actually I hope it's just one. This one battery is the only one to show an erroneous low temperature alarm. First, the entire stack limited itself to about 89% charge, and progressively over the course of a couple months now won't get above a 82% charge. I've read about others having this issue, but haven't heard from any of them what their actual solution was.
I won't go into detail here, but you can read my other thread to learn more about the problem:

Why Does My Battery Bank Now Top Out at Only 88% Capacity?

I thought about this thread overnight and the only thing I can come up with is what I stated already: Disconnect communication between the BMS and the rest of the system and see what happens. Well thanks for the suggestions. How should I go about doing this? Just unplug the CAN cable on the top...

diysolarforum.com

The batteries are under a manufacturer warranty, and the manufacturer first suggested getting a laptop cable to run their batteryview software, They reached out to the distributor in Lima (the opposite end of the country from where we live) to request they sell me the cable. They asked them to get me the cable, and the distributor finally responded about a month later, saying that I will have to ship them the problematic battery. Long story short, I don't trust the distributor (you can search my old threads to learn why I feel they are a shady business). I fear that if I send them my battery, that they'll just sit on it for at least a month, and never really accomplish anything. If they ever send me the battery back, I can assume the problem will end up recurring. They are very frustrating to deal with. Why take an entire month to respond, and then not even obey the battery manufacturer by supplying me with the laptop cable, but instead demand that I disconnect my battery and send it to them. Not a very logical first step. Maybe there's a simple fix that doesn't require me to be without my battery/batteries for who knows how long.

The distributor could really screw us over in this situation. What if they retained the battery and ignored us for a long time? The authorities in this country are next to useless for resolving scams.

Anyway, I calculate a high probability that the distributor will not help us out satisfactorily. Not to mention the risk of irresponsible shipping companies in this country. I suggested the manufacturer let us use an alternative distributor (there are others in the country) if we ever need service. Still, I'd rather not send my equipment anywhere. I guess it's a matter of tiptoe-ing the line to learn what exactly I can do on my own to the batteries to not invalidate warranty. Last resort I assume would be sending back and forth from China, which would be a total nightmare.

What do you do when you're totally dependent on faulty hardware to provide your electricity?

 

[SilverbackMP]

Buy a fifth battery? And then keep one as a backup?
“Two is one and one is none.”

 

[Powderfilm]

Ive read that its beneficial to have some high C discharge after charging, to break some formed up cristals. Maybe your battery is so big that you always C/2-C/8? Try 1-3C load (depending on your battery rating) for a few % capacity and check if that helped?

Have you considered creating a dis/charge curve of each cell?

Also, check for IR of the cells. That tells the most as far as knowing it will be a resistor and leech energy, corrupting the cells capacity and the entire system. You may even notice it with some thermal-camera if alot of energy dispate in heat?
There is acutally some A.I. driven online program: With the values you measure, it tells you how many cycles it got threw already and predicts its health. That could maybe give you a hint too if the cell just cycled already quite often.

Website:

Zell-Vorhersage

lili.fortyone.ai

(after reading it again I am not sure if its only intended for 18650 cells. Anyways, maybe going this direction still helps you)

Greets

Ps.: Opening a topic for replacing a BMS is funny... that should be a no brainer and google itself quick.

 

[time2roll]

I would simply order a new battery from China and replace it. Assuming that works, see if the faulty battery can be warranty adjusted by a local dealer.

At some point I would be planning on a full second set to run in parallel to avoid losing power if there is trouble in the future. The question is to buy 3 or 4 depending on the warranty resolution.

 

[hclarkx]

If I'm reading correctly, you are saying that a faulty low temperature alarm is the problem. And I gather it is curtailing charging prematurely?

If that's the case, and you are comfortable working inside of a battery, you could replace the BMS with an after market one. Or try just detecting the temperature sensor if you don't really need it. You'll void the warranty, but that does not sound a problem since it's worthless in any event. If the battery is in a sealed case that is not meant to be opened, this option gets a bit complicated since you don't want to carve into the cells as you take the top off of the case.

I recently had a BMS failure in a commercial battery. Since the cells are very reliable, I voided the warranty and replaced the BMS myself. Opening the battery was the most difficult part of the operation.

 

[AgroVenturesPeru]

If I'm reading correctly, you are saying that a faulty low temperature alarm is the problem. And I gather it is curtailing charging prematurely?

If that's the case, and you are comfortable working inside of a battery, you could replace the BMS with an after market one. Or try just detecting the temperature sensor if you don't really need it. You'll void the warranty, but that does not sound a problem since it's worthless in any event. If the battery is in a sealed case that is not meant to be opened, this option gets a bit complicated since you don't want to carve into the cells as you take the top off of the case.

I recently had a BMS failure in a commercial battery. Since the cells are very reliable, I voided the warranty and replaced the BMS myself. Opening the battery was the most difficult part of the operation.

That's almost right, except the faulty low temperature alarm is a separate issue that pops up every once in a while. The main issue is that the stack has completely lost the ability to charge to full capacity, and slowly but surely keeps downregulating. I first noticed the system stuck at 88%, now a couple months later it won't charge above a 82% SOC.

I'm really not techie enough for any of the suggestions given in this thread. One of these battery modules is like $2000 in this country. I'd rather not void the warranty. Unfortunately the only official distributor of Pylontech batteries in Peru is a company on the opposite side of the country that has shown that they have horrible customer service.

To clarify some of the other responses here, I won't be replacing a BMS or any other component. If anything I'm just going to replace the battery that seems to be causing the limiting issues. I don't have another 8 grand to buy back up batteries, and even if I did, I wouldn't buy more of the same brand of battery that couldn't even last a year without generating a problem.

First step is I'm going to order some cables to connect to the console port on the batteries and run the BatteryView software on my laptop, which was suggested by Pylontech to be able to view voltages of individual cells. Not sure what else you can do with that software.

Just want to do a little more diagnosing on my end, before I risk having the battery shipped across the country twice and letting a dubious distributor have their way with the unit for who knows how long. Others have suggested I shuffle the batteries in my stack or disconnect the problematic battery to see if the other three will charge to 100% on their own.

 

[hclarkx]

Really need more information to help. I think key is what voltages you are seeing and under what conditions. I.e., are you using voltage readings to back up the SOC readings. And confirm that the four stacked batteries are remaining in balance.

 

[AgroVenturesPeru]

Really need more information to help. I think key is what voltages you are seeing and under what conditions. I.e., are you using voltage readings to back up the SOC readings. And confirm that the four stacked batteries are remaining in balance.

How should I do this? Just stick my multi-meter on the pos and neg terminals of each battery? Their is a software given to me by the battery manufacturer that views more specifics such as individual cell data, but as usual, the distributor is not helpful in acquiring the cables I need for that.