JT1

Hi all, to add my 2 cents. I have recently had 5 x 2000’s returned to the supplier for evaluation. Installed in 2020 and registered with Pylontech for extended warranty. Two batteries recently started flashing alarm with no charge occurring and I contacted my installer as a result. The 2 batteries in question were horrendously swollen and the other 3 already starting to burst casings. I don’t have any graphs or further information. Only that I had what I believe was a good installer install my system (recommended by Solar Advice) and never played with anything i shouldn’t. I never pushed the batteries all that hard nor had more than a few trips on the inverter. 2 batteries to 1 x 5kw Deye and 4 batteries to another 5kw Deye covering 2 of my 3 phases. 1 battery seems to be ok at present. Patiently waiting for a view from the supplier with a way forward. 

@Calvin, Remember on first image Pack #1 - #5 is connected to Inverter 1 and Pack 6-10 (of which only 6,7,8 in image due to 8 limit on monitoring) is connected to inverter 2 hence why the 3 batteries are at different charge states as opposed to Pack#5 (pack 1 to 5 is at same voltage levels managed by inverter 1 which is 0.1-0.2v apart on batteries). Monitoring cables are split across cabinets but that does not influence charge rates per inverter and balancing battery voltages per inverter. Charge rates differ from each inverter and it will charge as per set max absorp and max float. I will check to add a bus bar but from stats I see batteries are within 0.1-0.2v from each other per inverter 5 packs. I maintained these batteries well on temps & DOD but seems 1000-1200 Cycles max. Only time will tell Pylontechs quality or if Wiring issue since I have 2 x US3000C on a single Inverter for 2 years now at another property and 2 x US2000b plus for around 3 years at a 3rd location. I do not monitor these batteries daily as with my own home batteries. I will remove the US2000b Plus next week and check max and min cell voltages on full charge on a monitoring system or via BatteryView and drained charge since it was installed on a single inverter since purchased.

Maybe a little harsh: they did replace 2 batteries under warranty, despite them being installed incorrectly.

This is how it should be connected on the BAT side, according to the Axpert Paralleling Guide:
 
But maybe that it IS connected like this in reality, and @JT1 just don't know it, since he was not the one who did all the DC wiring.
Anyway, batteries went belly-up, Pylontech's legendary 10-years warranty proved itself being non-existent => time to rip it off and replace with something better. 😕
 

@JT1 
Sadly this industry is awash with tales of "certified installers" who are not competent - read this forum for many examples.
 
A bad installation does not guarantee instant failure - abused batteries will simply have a shorter lifespan.  Whether abused or not, "identical" batteries will not all fail at the same time.
 
Irrespective of all the certificates, the fact remains that the installation is wrong.  I would take it up with the installer (assuming he is still in business...), but either way I would get it corrected.

Thanks for the answer. So the inverters are in parallel on the AC side and all the batteries are connected in parallel too, in a common DC BUS?
 
I am using Pylontech too (16 x US3000), since I was looking for a rack form-factor and by the time I bought first one, Pylontech was the only manufacturer with a rack-mount option. As of today there are dozens of rack-mount alternatives to choose from.
So far mine are running okay, but they have just 5 years  and much less than 1000 cycles (can check the exact cycles later).
Anyway, for the future it might be better to choose a manufacturer that is using standard prismatic cells with the screw terminals. Should some of the cells fail, one would be able to buy the replacement anywhere and then just plug it in and rebalance.
(Problem with Pylontech is that they are using 25Ah pouch cells, where US2000 has two connected in parallel, US3000 has three, etc. This design is basically non-repairable and prone to self-destruction in a case that one of these paralleled pouches is weaker than the other. Problem with some other manufacturers is, that even when they are utilizing prismatic cells, their terminals are welded, therefore quite hard to replace.)
 
 
 

I have a 6 year old installation in a 4 x 5kW Axpert Inverter setup as attached with 20 x Pylontech US2000 Plus (And some new US2000C Top batteries in Cabinets for failed US2000C Plus Replacements). US2000 Plus Batteries started failing 1 or 2 at a time since 2 years ago with 900-1100 cycles on the batteries. Initially when installed in 2017 Pylontech approved the 53.2v Float/Absorption charge settings for the 10 year warranty and it was submitted to them by installer. 2 Years ago they replaced 2 batteries. The voltages on inverters was then adjusted by installer due to 2 batteries failing to a lower voltage 52.7v Absorption and 52.4v float, according to installer Pylontech's new recommendation is lower voltages to prevent overvoltage which still indicates the batteries are charged 100% full after the settings changed, so voltages seemed fine.  Earlier this year another 2 batteries started to discharge faster than other's and Pylontech did not replace it and attributed it to overcharge voltages. How can 2 batteries in 2 cabinets fail out of 20 (4 x 5 Strings of batteries, 5 batteries per inverter) Insurance declined physical or electrical damage claim and attributed it to wear and tear. Pylontech should cover battery usage (Wear and Tear) for 10 years correct ? If warranty not covering these batteries and insurance not covering it under electrical/surge damage does anyone have a resolution here please ? Last week I noticed another battery discharging faster than other's and since Pylontech is not replacing I opened it to check if swollen. It was swollen as attached as the previous ones which they did not replace so I did not care I if voided the warranty by opening it. Today another US2000 Plus started discharging faster than other's. Some sample monitoring screenshots attached. The 10V Battery on the left side of image attached was swollen, on other 2 batteries the 30V right side was swollen. Totally random and different inverters on these batteries. All battery cycles since installed 6 years ago are less than 1200 Cycles. Since day 1 battery monitoring was done (1st ICC then then swopped to Solar Assistant), battery voltages never exceed 53.2v and the past year never exceeded 52.7v after lower voltages set on inverters. Cut-off voltage done before reaching minimum voltages around 20% battery remaining on cut-off but low voltage according to Pylontech warranty replacement was not the problem, overvoltage was. Battery temps as per 3 months graphs indicates battery temps are within suitable temp ranges. I can only monitor 8 batteries at a time due to US2000 Plus limitations but I swop the monitoring console cable to a different set of batteries every 3 or 4 months to check if batteries still good. So 6 Batteries failed out of 20 and Pylontech attributes this to overvoltage and only 2 replaced. 1 I opened so voided warranty and the one I checked today not opened yet. Any ideas since I will rather not recommend Pylontech for honoring their 10 years warranty at this stage. I also queried them dates of which overvoltages occured but they just ignored me.

To be clear: BrandX is not PylonTech.

I'm not sure any other brand would have given you significantly better service. My system is about 5.5 years old now, but the batteries are younger. This is because I originally had a different brand of battery. Let's call them BrandX and say that they were replaced with Freedom Won.

Anyway, round about the 3 year mark the BrandX batteries started showing much quicker drop in SOC under load when there was no PV. OK... so I understand that things decay and don't last forever, and, like most of us, this is my first PV system and I'm still learning what it is to live with this system, and for all I know this is a usual drop in performance after 3 years. 

So I asked BrandX (which gave them a way to pre-empt the shenanigans that followed) and my installer: Is this a usual drop off of performance after 3 years? If I'd been told yes, I'd have filed this away under "lessons learned", and would have adjusted some timer switches to run some loads a bit later in the day when PV is available. 

But nobody would give an answer to that question. Instead BrandX took my batteries away for testing leaving me with no protection (and implying a response of "no" to my question), but I suppose it's fair to let them examine and test if it's a potential warranty claim. They then said that the batteries were absolutely fine, so I asked them to explain the change in performance - which I could show. They then sent technicians out who plugged in some diagnostic software and said I'd been overcharging. I asked them why they'd said the batteries were OK and are now saying that actually they are damaged and have been misused.

No answer.

Then I asked to see the data. There was an overcharge event in the log but 
1) it was in excess of what my inverter can deliver to (or demand from) the batteries
2) it predated my purchase of the batteries

Anyway... we danced a few times around the floor with no definitive answers to any questions. 

I eventually concluded that all this stuff about 10 year warranties is not worth what it's printed on because nobody's been in this game for 10 years anyway. So what does anybody know?

Not much comfort for you there, I'm afraid. I am a bit jealous of your setup because you have multiple small batteries, so if one or two go belly up or have to be taken away then you still have some protection. I currently have one Freedom Won 10/8, and if they want to take that away for testing then I am left with nothing.
 

Well, Pylontech buys these cells from some Chinese manufacturer or two or three. The manufacturer gives a guarantee for the cells, but it is probably just made up, thumb suck. Pylontech then puts a thumb suck guarantee on their batteries, hoping for the best. They also know they cannot put a short guarantee as their batteries won't sell, so they put an inflated 10 year guarantee to compete with other battery manufacturers that thumb suck as well. Now after all this thumb sucking the thumb is no longer in good condition. If things go wrong, which most likely it will, they will just insist that the customer is at fault, stuff like like overvoltage, bad battery temp, overcharging, undercharging, etc, whatever they can thumb suck to get out of a claim.

@dropkickWill use an old android 10" Tablet for sure and permanently on charge for a display with mqtt values. Will be a lot cheaper. Can also fit more counter values on a larger display than currently on my phone without scrolling. I Mostly check the phone if bad weather and then switch over to utility if batteries is low to charge from utility, especially before load shedding periods in the area. For remote switching between utility/solar I just configured a ddns record and forward mqtt on port 1883 to the pi via router. The mode switch button is Inverter/SetMode on ICC Variable, not a lot of people use ICC to max potential.

That's not a bug, that's a feature!    You''re supposed to look at it like this:   The "MS" stands for MaSter. As far as we can tell, "HS" is their attempt at making two seven-segment characters look like "MS", using their rather poor "font".
It's impossible to please everyone, but the changes are all meant to be improvements. They should all be mentioned in the AussieView™ manual.
If after reading the manual you think that something is unreadable or missing etc, please post specifics. In particular, the keys don't work the same in information display mode.
All I can think of is that perhaps some monitoring software is running in the background (e.g. you might have tried WatchPower and thought that closing the window would stop it from running. You need to use the system tray to exit, as explained in the middle of this post (NOTE: the software in that post is not the latest).

@Coulomb and @weber changed the text a bit to make it more readable. Some of the 7 segment  script is difficult to implement (the letter M was one of the ones they had trouble with).

Currently I have 4 x RCT (Voltronic) 5kva inverters in parallel. The settings are set to charge the batteries 10A max from Utility and 25A per Battery for the Pylontech US2000 2.4kw Batteries. It seems the batteries does not reach above 51.5volts. I have the setting for Parameter 1 = SOL (Solar Only) set and did not mess around with the charging voltages set by installer since do not have a guide for it. The installer who helped with the setup recommended solar only and said it will charge during day with Solar and during Night with Eskom. This does not make sense to me. The inverter is on bypass a lot during night and I am trying to resolve this (Even this morning when panels could supply load it was on bypass and panels charged batteries). When I manually dropped the Eskom breakers the load supply switched over to the PV Panels/Batteries but the power to the house dropped for around 1 sec and there was an interruption on power which caused appliances to power cycle for that short period. The load is around 700w-900w during night per inverter and 900w-1.6kw during day per inverter when I do not switch-on the manual changeovers for some plugs I have on changeover between Eskom and Inverters. I have Parameter 1 set to SBU this morning hoping it will solve the problem with the batteries charging. Is there anything else that can be checked ? Thank you @Chris Hobson for the pics of your ground mount panels. It took me a while to build them all with some help and I change it a bit to ensure the angles can be adjusted best I could do was 11 degrees to 50 degrees variable adjustments. Posted some pics