Tinbum

I think you need to give much more detail for people to be able to comment. Eg We don't know if it has worked in the past, what batteries, how they are connected etc etc.

Just had a quick glance at the manual and it shows a warning here and says pretty well what I thought. and It also explains here how the system works. A reinstall as a first install system would have sorted it but making sure that other conditions above are met first to ensure no high surge currents that could damage things. this is for multiple strings though. A full read of the manual is always a good thing.

Pylontech will have factored that into the design so you won't need a balancer. I'm sure it's because the new ones were fitted at a vastly different soc as I said above. They probably will balance, as shown by the 1A setting but it will take weeks / months. Edit The new batteries need removing then the old batteries discharging to the same soc as the new ones and then the new ones adding in again. Their may be other ways depending on what you have available.

Ah, that's because the BMS is limiting it. In your first shot the battery is at 52% which is when you say it reaches its max SOC. I'm pretty sure your problem is because you fitted the new batteries when they were at 52% SOC (or perhaps say 30% and SOC is average), as supplied by Pylontech and the older ones were 100% SOC ie fully charged. (Edit probably the opposite way round as the manual says they come at 100% soc unless otherwise requested by supplier.)

Did you balance the batteries before fitting? As they are in series as soon as a single battery gets to 100% SOC it will stop any current flowing through the others. (Unless Pylontech have a way of overcoming this internally).

Think you need to alter this.

I'd say it doesn't really matter, both will work fine, but it would more depend on how you wish to fuse and if you want the ability to isolate if you have a problem.

Have you looked at the data that Growatt send over the CAN bus? It's massive!! Growatt BMS CAN-Bus-protocol-low-voltage-V1.08.pdf

@Shortcut What is the firmware version in your batteries?

That's a strange one to cause problems as it's only cell id's, isn't it..

I have done a lot of programing to translate CAN communication so that different systems can be combined and communicate with each other. One system I am using uses Growatt batteries. Growatt have their own protocol for which I have written a program to translate it to Pylontech so they can be used with none Growatt inverters. Growatt batteries are one that do require a signal from the inverter showing that it is present or that won't power up and they have been like that for many many years. I have never heard of any Pylontech 2000C, 3000C or 5000 requiring that and many people use them without communication.

I'm not stopping him. I'd already said about the firmware!!

No, it's the inverter shutting down because it hasn't communication. It's not the other way round.

They are normal batteries with a normal bms unless they have added something in the last firmware which I very much doubt.

That's a new one on me if they mean the batteries require comms, unless its something new in the firmware. It would be possible to do as inverters do 'tell' the battery they are there. I would think they mean the inverter requires communication. I don't know the Victron equipment so don't know if it has 'non communication' manual settings. Presumed you'd already set them.

Should work fine if newest battery is master. We need more details on what the trips are to diagnose though.. Use BatteryView.

Now that's clearer. You won't achieve anything by looking at the older battery it's a different kettle of fish.. You should have a fuse / breaker on your battery anyway. Your system is badly designed and you don't have enough batteries for the inverter. Until you fix that you will have problems. If warranty is refused then I would open the battery up, check the fuses, replace with the same if needed and then buy more batteries.

In your first post ; You said that the batteries were brand new, I didn't know that they were still making the US5000b. What are the production dates on the batteries? The link to the battery teardown thread starts with the older batteries, this may give you a clue as to how the fusing possibly is- thought they don't have the CB.

Sorry I'm getting confused with the other thread where the battery is 18 months old.

Have a look at That shows a US3000C later on in the thread which should be fairly similar. (The fuses are chips)

That's a bit of an awkward one. It should protect the battery, so has failed in that, but then the system should be designed properly in the first place, as I mentioned earlier, and it shouldn't be required!

The Pylontech do a soft start and will detect this as a short circuit so it shouldn't really damage the BMS. (I've experienced this many years ago with an SMA inverter and no damage was done).

Reading the inverter manual is helpful and a search on here will give you recommended settings depending on your battery settings up.

Cell 11 is fine.