Tinbum

You need to find out why this has happened, before the other battery goes the same way.. Give details of your setup.

I thought that they would reject it. You really need to try to file a claim against the inverter company.

Read the manual (US2000C or US5000) for the order to put them in- it's all in their.

Put the the newest as master.

Download the manual for the US5000 batteries and it will show you what order to place them in. I would think you shouldn't need a hub

What year / age US5000?

Yes, I think this is an inverter fault that has caused the battery problems. I would probably ask the installer to confirm the settings are ok and get them to actually measure the voltage coming out of the inverter when the inverter thinks it is at 53.2v. It's a pity you dont seem to have the log files for the batteries from initial installation date. I would check that again in battery view.

I'm pretty certain they will throw it out due to over voltage. What about the installer? I'm in the UK so no.

I would try that first and if they aren't helpful then go to Pylontech themselves. Did you register for the extended warranty?

Your chances are good as long as the battery hasn't gone overvoltage ie above 54v. How old is it though?

The battery will record logs all the time, you just need to download them with BatteyView. I suspect you have a cell in that battery that is going over voltage very easily/quickly. The battery disconnects from the bus (inverter/other batteries). The bms then re-balances the cell, the battery connects again, probably cell goes over voltage again and cycle continues until all cells are balanced. That's when it then reaches 100% SOC. Serial number erased just as a security measure. I would expect you to be making a claim for a replacement as it's not normal behaviour. (Edit Cell 8 looks to be a bit different to the rest so it could actually be that that cell is always low causing the other cells to be higher). Was this the first battery you bought in your setup?

I would use battery view to pull the logs for the second battery and post here please. Redact serial number. I think the second battery is disconnecting due to high cell voltages. Looks as if it may have a bad cell. The balancer does seem to equalize it though eventually, but not normal behaviour.

To get back on thread how did it go?

Great, can you pull the cell high and low values and the current for the battery 2 at the same time as the voltages.

You know quite well I am referring to the advice of not using communication.

Where is the voltage data coming from? What software?

The old US2000's should have worked fine with the US3000C's, you just have to make sure you put them in positions 2 to 8. Pylontech are reliable batteries, most problems come from charging at too high voltage most often caused by poor inverter control. Victron did start to limit their max charge voltage in the firmware from the 53.2v to 52.5v. Did you keep you Victron system updated and did you initially just run it with the US2000's alone? Pylontech now reduce the max charge requested from 53.2v to 52.8v in their battery firmware. Using CAN communication should update values automatically in your Victron system. I would ditch the LVhub and just connect the master battery directly to the Victron. Should you keep with Pylontech and expand beyond 16 batteries you could then put it back in.

They are not extreme at all, inverter regulation by battery temperature is used all the time. Forums like this attract people that are having problems and you don't hear about the 10's, 100's, 1000's of thousands that don't have a problem. Many of the problems on here boil down to bad installers, poor design and probably most of all poor quality inverters. This thread is nothing to do with the author neglecting proper inverter settings. Read the thread again from the start. Your advice is bad.

I would remove the bad batteries, remove the hub. Connecting the new batteries is pretty simple then. It's worth looking atvthe logs of the old batteries to see what voltages they have been up to.

You can have 16 batteries without a hub.

Not a fantasy, reality. Just because your set up can't do it doesn't mean another can't. It's not just overheating batteries it's also applies to batteries that are cold. Why limit charging current in the inverter, that would apply all the time, and limit your charging for no reason and wasting production? What happens when you have a sunny morning, but have limited the current, and then the afternoon is dull and you don't get enough to recharge you batteries? This is a public forum and advice should be correct for ANY scenario.

Wrong they are charge managing parameters. In your system if a battery overheats it shuts down. The inverter keeps charging at the same current, the next battery overheats and shuts down until they have all shut down. In a connected system the inverter reduces it's current as the battery warms and the whole system stays up and running. Unconnected is dangerous. If yours, say you have 2 batteries and you set the inverter current at 2x the batteries max charge current and then a battery bms shuts down you will then be putting 2x the max charge current into 1 battery. In a connected system inverter will know to reduce the charge current to the max a single battery can take.

That's what pretty much what any decent BMS does. The Pylontech BMS has done that here but it's voltages are set a bit on the high side- hence the later revised voltages in the latest firmware. Here though if the inverter had been working correctly the voltages would never have got up high enough to require the BMS to physically intervene. It also enables infinite ramping down of voltage / current and not just on/off or limiting to say 10A.

The JK BMs has comms.

Battery charging should not just be controlled by battery voltage. The BMS takes into account individual cell voltages, cell temperatures, charge currents, discharge currents etc etc. I think this thread has shown the information in the inverter lies.