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Pylontech Battery High Volt Alarm

Hello. I did search to see if there were posts about my issue but no answers were a close match. I have a bank of 10 x Pylontech US3000C batteries. I am off-grid and only charge the batteries with solar. Recently I have been getting fleeting high volt alarms from (I assume) the Pylontech BMS. These display on my Cerbo console and last for between 30 and 50 seconds and then return to normal.

These alarms occur when the state of charge is higher than 98% and the MPPT chargers are really cranking. This morning my MPPTs were providing 10kW, with 3.5kW going to a hot water service and the remainder to the batteries. As the SOC ticked over 98% the supply to the batteries did start to reduce, but not quickly enough to prevent the high volt alarm. When the high volt alarm came up I could see that the system was still pushing more than 3.5kW into the batteries.

What is curious is that the alarm reports that the voltage is 52.27V, which is actually lower than the float voltage the DVCC sets (52.3V). I was unable to gain physical access the batteries before the alarm cleared and when I did gain access there were no abnormal status indicators on any of the US3000C units.

I will add that this has only occurred on four separate days during the past four months that the system has been commissioned, but three of them have been this month.

I do not have an interface cable which would allow me to interrogate the batteries. If anyone reading this has the details of how to make up the cable to check the batteries, and/or a link to the software download, I would appreciate it if they would make them available to me. I am and electronics tech. and won't be blundering about in there, making more trouble for myself. I'm not stressing about this but it would be nice to eliminate the problem.

Rusty

battery chargingPylontech
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3 Answers
Alexandra avatar image
Alexandra answered ·

@away

The high voltage alarms are likely individual cell voltages that are high. It usually does not have anything to do with the total pack voltage. The BMS should bring them under control by slowing/stopping charge.

Best way to check that is to use VRM advanced and load the cell high low widget. And the battery alarms and warnings widget. You can see when it is being triggered.

Or look on the console under battery parameters you will see some of the information there (depends on the pylontec firmware).

Eliminating the 'problem' is not possible. Even after the batteries have calmed down in a new install you will see them from time to time.

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nickdb avatar image
nickdb answered ·

Sounds like a normal balancing alarm. If you check min/max cell voltages you will probably find one ore more is above thresholds. That is a BMS generated event. High voltage alarms on pylons (and others) is thoroughly documented on many posts.

Transients are normal, especially on new batteries, after newer ones are added, after deep discharging, or spending insufficient time at full charge.

Nothing you can do apart from let them settle and balance, it always goes away and it won't break anything for such minor duration. Some would fiddle with manually lowering the voltage, on your description I would not bother though.

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Alex Pescaru avatar image
Alex Pescaru answered ·

Hi @away

Below the software you seek.

Inside also instructions to build the cable.

Have fun!

Alex

batteryview_usxxxx_series_3-0-29.zip


3 comments
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away avatar image away commented ·
Thank you Alex. Exactly what I was after.


Rusty

1 Like 1 ·
nickdb avatar image nickdb ♦♦ away commented ·
Just remember you can get this data from the GX and VRM (cell ID and Voltage).

Be careful with batteryview, it is not an end-user tool, but the internet has turned it into one and some people have royally ruined their batteries by following advice out of context.

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Alex Pescaru avatar image Alex Pescaru away commented ·

Glad that I could be of service, but also take Nick's advice into consideration and be careful with the Batteryview.

Stay away from the "Login" and "Update" options, unless you know what you are doing. :-))

Anything else is a go.

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