If anyone needs Pylontech batteries....

[Oldgreybeard]

Just watched this about what seems to be poor service from Pylontech:



I've watched a few of this chaps videos, and whilst I agree with his conclusions that the service he's had from his supplier and Pylontech are not up to the standard that someone buying something like a Macbook might expect, none of the issues he's had come as any surprise to me. I've been buying batteries, controllers, chargers etc from China since the early 2000's. The very first lesson I learned was that you cannot trust any specification and that any warranty provided on goods shipped direct from China wasn't worth the paper it was printed on.

Had my fingers burned a couple of times by outright conmen trading on sites like Aliexpress, and I've learned a lot about the way stuff is manufactured, the gross problems with specifications and instructions often being a bit lacking, or just plain wrong, but the bottom line is that you get what you pay for in the main. If you want a battery system that will be plug-and-play, have good installation and operating instructions, and will have customer support on the end of the phone, then you have to buy something like the Tesla Powerwall. Not the most flexible or adaptable system, but it will work reliably and it will be supported for the duration of the warranty.

One thing I've learned when dealing directly with Chinese vendors and manufacturers is that the concept of lifetime support for products is just an alien one for many of them. This isn't really malice, it's just a cultural difference where our expectations from a supplier or manufacturer are a million miles away from the expectations of a domestic market customer, and there are a lot of companies that really just don't get this at all.

If there is one takeaway from this video and the others that this chap has produced, then it is that you need to REALLY do your homework when buying items from a range of different suppliers and manufacturers and then trying to get them to all integrate and work nicely with each other.

Interestingly, in this specific case I think the advice he's been given makes sense, in that he has got a problem with the Modbus daisy chaining protocol. I may be wrong, but I have a faint recollection that there was an issue with stacking more than six Pylontech batteries at one time, in that the Modbus relaying part (where data from upstream batteries gets combined with the data from other batteries as it ripples down the stack) wouldn't always work reliably. I very strongly suspect that the problem he's seeing is just a comms issue, rather than a major problem with the batteries themselves.

It's a bit like our Sofar RS485 comms, which is also flaky as hell. There's a bug in the Sofar firmware that means that about 1 in 50 Modbus packets has a CRC error. It's not an issue with the physical link layer, as such, it seems that for some reason the Sofar firmware just doesn't reliably calculate the CRC checksum sometimes. The data is fine, valid and accurate as far as I can tell, the only issue is that the CRC is wrong. I've just adapted my code to ignore the CRC errors and everything then works absolutely fine, it's just a quirk that I can live with (as the data is only feeding Home Assistant, anyway).

The key thing for me from this video would not be the headline, of not ever buying Pylontech products, but it would be to lower your expectations when it comes to customer service from the manufacturer. Pylontech are a hell of a lot better than very many far-eastern manufacturers, but none offer customer service of the sort of standard from companies like Victron or SMA. As the old saying goes, "you pay your money and take your choice". In many ways I feel sorry for this chap, as all through his journey into building an off-grid system he seems to have suffered a fair bit from not fully understanding what it was he was buying, or what level of support was available.