Having problems with my Pylontech US5000

[Spanish Flyer]

Purchased two months ago to add some storage to my 6 x US3000C battery bank; it was a bit complicated to get it to work together with the other batteries, but in the end almost everything was fine (I say everything because there was a delay on the charging process, being the US5000 the last to fully charge).
After about a month I got the dreaded red led on constant on this battery, so after trying to recover it the best way I could think of, I contacted Pylontech in China and they sent me a file with the latest update of its firmware.

Prior to trying to flash the new firmware, the battery still had one green led flashing every 3 seconds (the one that shows the standby condition of the unit).
Using the latest BatteryView version 3.0.28 and the *.bin file I received from Pylontech I attempted to flash the new version (having the US5000 alone with no other connection but the modified USB-RS485 cable)... It got up to 85% completion and then failed to accomplish the goal.

I had previously sent the "Event" file to Pylontech and they informed me that the battery had been overcharged at some stage, so my warranty was void!!
Can't understand why this happened since it had been working with the other 6 US3000C's and they are all fine (top charging voltage 52.5 V).
Anyway after the attempted Flash, the battery was completely dead; no more green flashing led and voltage across the terminals 0.0 V. BatteryView is no longer able to access the battery data....
Taking the matter into my own hands, and knowing that my warranty had gone out the window, I removed the battery from the rest of the stack, turned it upsidedown and removed the first small cover; all the BMS and wiring looked perfect with no burnt smell or anything that could show any physical damage there... I then proceeded to remove the other cover, the one that holds all the battery cells, but after making sure I had left no screws in place, here is where I could not continue with my inspection, since this main cover seems to be glued to the main battery body; the sides do lift slightly, but the center will not give way.
My first goal was to charge cell by cell with my lab adjustable 5A charger, but don't want to force this last cover.
So my MOST IMPORTANT question is: Has anyone faced this same problem with the cover? Is it glued or just melted due to overheat when overcharged?

I don't want to continue till someone knows about this problem.
Besides of that, I now have the added issue of trying to re-flash the battery,... what a disaster : (

 

[ProfLinux]

I cannot help you sorry, but I find it strange they claim it was overcharged - is this not exactly what the BMS inside should prevent?

 

[Spanish Flyer]

Thanks anyway ProfLinux, and I fully agree with you, I actually asked Pylontech CN that same question and this is what I got as reply:
"Our battery has a protection system and that is why the BMS has alarms and the battery stop working to protect the battery cells."
Can you believe it??
So in order to avoid damaging the battery they... damage the battery in such a way that you cannot fix it, when a simple trip device that you can reset without opening the case would have done the job perfectly...

 

[ProfLinux]

To be honest I don't belive that excuse. A BMS is there to cut-off in case voltage is too high or low, I guess they are just trying to talk you out of claiming warranty. This is really sad to hear, I was also thinking about buying a pylontech 5000, to not have to hit-or-miss with the no-name pre-assembled batteries you get from aliexpress. reading here that there warranty claimes are basically useless, makes be hesitant to pay the higher price they ask for.

I would try to negotiate. If your cells are, what they call, overcharged, then this is no reason for the rest of the BMS to stop working. Why not ask them to exchange the electronics for new circuit boards, while you keep the old cells? Those chinese companies are typically also very sensitive regarding bad publicity, so a blog and a youtube-clip often do wonders.

 

[Spanish Flyer]

And Damaged it was.
However I got help from Growatt CN and they gave me all the help I could get, I was actually surprised that even though I had no help from my rep or european representatives for that matter, Growatt China made the right move in trying to help me.
In the end and after recovering some data using the latest version of BatteryView, it was very clear that the battery had suffered from overcharging when I tried to charge it with my DEYE Sun 5000, while having the CAN COMM cable connected to another inverter (Growatt SPF5000ES)... That error" rendered it as a warranty void failure; now I have to send the "big Brick" to the shop who sold me the battery, so they can (if they can...) replace the BMS and return it to me after paying a hefty sum and of course waiting for it to be returned in the best case by the end of the summer.
What is clear is that Pylontech should protect the battery from overcharging by simply adding a SOC limit device that could be rearmed externally and not like the bees, thay if they sting you protecting their media, they end up dying; not very clever...
So now I want to try and replace the BMS by myself, but wonder if anyone knows if such items can be purchased at all...
Best regards

 

[AlaskanNoob]

...it was very clear that the battery had suffered from overcharging when I tried to charge it with my DEYE Sun 5000, while having the CAN COMM cable connected to another inverter (Growatt SPF5000ES)...

So are you saying that the inverter was trying to charge the battery at the same time the DEYE was? At that resulted in an overcharge?