GoodweYES

Interesting. If the BMS report cannot be extracted what is the manufacturer basing their overvoltage assessment on. If the cause cannot be accurately determined based on facts and data it cannot be assumed to be an overvoltage even that caused this, the opposite should apply rather.
It looks like the manufacturer is doing everything possible to avoid honoring their warranty and supporting their product and customers.

My take is that the distributers and manufacturers warranties and fine print exist to protect them, not the customer. And they can throw the book at you and that warranty might as well not exist. Here is an example of some clauses, and no, I shall not mention the importer/distributer.
If you read some of the clauses, then from the outset your battery's warranty could be voided within the first year unless you have a hermetically sealed environment. Just some of the clauses:

Batteries are not user serviceable and any attempt to tamper with or open the battery will void warranty. 
Contamination of battery by dust, water, corrosive material, or any other matter will void warranty.
Batteries must remain between 5-25°C while stored and unused, warranty period will be reduced by 50% for every 10°C increase (35°C+) above this.
Warranties are non-transferable, and only applies to the original purchaser

There is no definition of what measure is considered contamination. Dust will settle inside the battery over time, has to, if there is air circulation, which is part of the design to control temperatures. Any dust  contamination inside is subjective and you are at their mercy. You can't clean your battery inside as that voids the warranty, thus there will be dust contamination.

So in essence if they apply the "dust" clause the cost of getting a lawyer to take them on will probably be more than the price of a new battery. 

I paid for my battery without any visions of honorable warranty claims. Should the day arrive that I need it, then a repair under warranty I shall regard as a bonus.

Hi, Just a warning  see my alert/experience dealing with Dyness guarantee
 https://powerforum.co.za/topic/18042-dyness-10year-warranty-anyone-else-had-a-legitimate-warranty-rejected/#comment-159143
 

Did you ask for the BMS data that they pulled from the battery? You should
Did they supply the details of the overvoltage event or events. Again you want then to supply this information to you.
Generally an overvoltage alarm will be triggered at 3.6v for a LFP cells. The cell will still continue to charge up to 3.65v when an overvoltage protect will be triggered and the battery (all cells) will stop charging. Both 3.6v and 3.65v is easily manageable for LFP cells ,and it should not cause cell failure.
You need to check the data for
1. Frequency of the overvoltage events (does it occur daily or is it random).
2. Look at the timestamp of the events. Did they at least occur after the batteries were installed at your premises.
3. Do the overvoltage events occur on all cells or just the one cell with the issue. If it is only occurring on the one cell with the issue then this is a dead giveaway that the cell was likely of poor quality from the start. By example if the swollen cel was at 3.65v while the others cells were still at 3.35v then it is clear that the overvoltage alarm was caused by a poor cell and not actually by an incorrect charge voltage.
4. Are there over voltage events for the battery as a whole or just at cell level. If the overvoltage is for the battery as a whole then the issue was likely caused by an incorrect charge voltage being supplied as opposed to an issue at cell level. Even using BMS communication is no guarantee of the correct charge voltage being applied.
Also ask for the BMS data of the other batteries in the bank to compare the data. If it is only one battery with this issue then this again points to poor quality cells that caused the issue ( or some installation issue).

Point -4- legal resolution.  Forget it.  The legal system only protects the ultra rich and the ultra poor.  You would be wasting your time and money.  Rather contact the local agent and make it quite clear that if the warranty is not upheld, you intend dragging the company name through the deepest mud you can find.  Especially on a forum like this, a reputation can suffer badly... 

You make some very valid points with 1, 2 & 3.

Slightly off point, but worth mentioning, is a story a friend recently told.  She has a 10+ year Victron inverter that stopped working.  The inverter went to a repair centre in Kuilsriver (not sure if these are the formal repair agents).  Anyway, the inverter was declared unserviceable.  She phoned, wanting to know exactly what the fault was.  They explained that the inverter had 3 PCBs.  First they would exchange the control PCB.  If that wouldn't fix things, they would replace the power PCB.  And if the fault would still persist, they would then replace the inter-connect/back-panel PCB.  However, the inverter being more than 10 years old is no longer supported and no spares are available.  She then contacted friends in the Netherlands who got confirmation from the Victron head office that this indeed is correct.

I can understand the 10-year limit on spares support.  What I can't understand, is why the local guys seem to only be PCB/module replacers just like BMW or Merc mechanics.  It sounds that no attempt is made in actual repair, i.e. fault tracing and replacing down to component level.

Some of the Victron MPPT chargers are completely potted.  On youtube people show how they cut the box open with angle grinder or hacksaw, just to replace a fuse.

You expect a 10 year guarantee.  Other companies can't even keep the spares for that period.  Granted, batteries and solar panels are somewhat different to a box of silicon.

Many good reputations are build on rubble.  I have forever ignored guarantees and am willing to break the tamper sticker on the first day.

They should definitely replace it or repair it at least ,give them hell. 

Hi,
 
I had a Dyness B3 4X battery stack installed by a supplier on 3 August 2020 . At that time the installer informed me that I had a 10 year warranty on the Dyness batteries.  The settings of the  Goodwe 5048 inverter was set on 50% DOD on grid and 80% of grid. One of the batteries failed and I requested my installer to assist. He informed me That CNBMSOLAR the Dyness service company refused as they said the battery was given over-voltage. Now I do not understand the logic as there were 4 Dyness B3 batteries in the stack with this being the second one in the stack and wired as Dyness prescribed by the installer. All the batteries have their own BMS and as well only one battery were set as the primary which was the top one.
 
Could you please advise me if I am correct in assuming that Dyness is shirking their responsibility as:
1) What is their basis or ground  to say there were over-voltage and should the batteries Dyness BMS not protect it?  I understand the swollen cells indicates overvoltage but their BMS and circuitry is to blame and should protect the cell  ? 
2) If the BMS failed is this not still/also the battery manufacturer issue?
3) How come all the other batteries in the stack are fine? Did their BMS work correctly and this batteries not? Is it still the manufacturer's issue? .
4) Anyone that has followed a legal resolution and what were the costs of this?
5) Do I have any recourse ie asking Goodwe why their inverter supplied overvoltage or will this just start a ping pong game in China with not respnsibility taken by anyone?
6) Any other recourse?
I would appreciate any advice as it would seem the battery manufacturer intends to not wanting to honor their warranty when there is cells that are swollen regardless if the failure is caused by the BMS or the poor quality selection of the wet cells that were used. If someone had a similar experience and got it resolved I would also appreciate some advice.
My advice in the mean time is to think carefully when buying Dyness batteries and you want to assume the 10 year battery warranty is valid when comparing to other brands. This one B3 battery failed after 2 year and 2 months and it was not really worked hard with  the full stack only going about 12 times to 80%dod and the rest of the time to 50%.  So the battery could have given me 1400 kWh out if the possible guaranteed 16800kWh ( 3.5 @80% dod x 6000 cycles ).  
 

Some interesting reading from SSEG.org.za
https://www.sseg.org.za/municipality/city-of-johannesburg-metropolitan/

Maybe old.....
City-Power-Embedded-PV-Generation-Application-Form-V2.pdf City_Power_Install_Standards.pdf

Hi see https://github.com/mletenay/home-assistant-goodwe-inverter/blob/master/custom_components/goodwe/goodwe_inverter.py for detail and say thank you to https://github.com/mletenay 

Hi see https://github.com/mletenay/home-assistant-goodwe-inverter/blob/master/custom_components/goodwe/goodwe_inverter.py for detail and say thank you to https://github.com/mletenay 

Hi see https://github.com/mletenay/home-assistant-goodwe-inverter/blob/master/custom_components/goodwe/goodwe_inverter.py for detail and say thank you to https://github.com/mletenay