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Pylontech US3000C / Venus GX / MPPT 150/35 High voltage alarm at 49.14V

Hi,


We have a new off grid solar install reporting Solar Charger [258] - Error code: #2 - Battery voltage too high, and is not charging battery, it is discharging and powering its load.


PylonTech US3000C

Venus GX, Firmware 2.93

MPPT 150/35, Firmware 1.47


I have read the info at: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom#high_voltage_warning_or_alarm_shown_on_battery_status


about this alarm being caused by imbalanced cells on newly installed batteries, but I don't think this is the case.


System reports Pylontech battery voltage 49.14V

1677884982021.png


Highest and lowest cell voltage reports 3.276, and battery gives OK accross the board.

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Battery CVL auto set by pylontech to 53.2V

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I have tried the advice linked above ("Note: The “Limit managed battery charge voltage” feature should be left OFF, unless you are experiencing “High Voltage” or “Internal Error” alarms. These alarms can indicate that there is an internal cell imbalance in the battery. It may be useful in this situation to enable this feature, and then adjust the voltage limit down so that the batteries are able to balance charge without reaching over voltage internally. ")


adjusting the Limit Managed Battery Charge Voltage all the way down to just above the voltage reported by the battery, and rebooting the Venus GX, but the high voltage alarm returns immediately after boot.

1677885591010.png


What is the next step to resolve this over voltage alarm and failure to charge?


Cheers


Pylontech
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3 Answers
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technology answered ·

Got it.... victron connect was not even listing the MPPT charger, because VRM 2 way comms was not enabled on the Venus GX..... Ugh.


Enable VRM 2 way communication on Venus GX (Settings > VRM Online portal > VRM 2 - way communication)

1678064843621.png

Victron Connect > VRM > *the site* > Devices then lists the Charger, and clicking it prompts to update chargers firmware. Alarm goes away, pylontech battery charges....




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matt1309 answered ·

Hi @Technology

I might be miles off here but what are the settings you've got within the charge controller itself. If the error is coming from the charge controller is there maybe a voltage setting in there that is incorrect.

I'm not too familiar with pylontech but just googled and can see they have 15cells in series. Many LiFePO4 battery packs use 16cells in series. If you've used default settings for LiFePO4 in MPPT you might have set absorption/float voltages too high for a 15cell battery pack, hence why voltage is peaking.



(Sorry if you already know this but this is the logic behind my guess):

It's worth noting that if cells are unbalanced they'd likely peak when charging and might drop down to a "normal voltage" when charge controller disconnects/stop charging (and balances kick in). However i don't think that's the case here as your cells seem a fair way under a high voltage. 53.2/15 = 3.55 per cell and yours are sitting at 3.27 per cell without being charged.

If they were 3.3-3.4v without charging then i'd maybe agree it was unbalanced cells and as soon as you added charging the 3.27 might peak to 3.55+ quickly, but 3.27 is a fair way off the steep part of the curve for LiFePO4 batteries in my opinion (i'd say 3.45 is the start of the steep part for most). So my guess is it's not due to unbalanced cells and instead maybe incorrect settings in MPPT.







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technology avatar image
technology answered ·

Hi Matt,


You might be onto something there. From the remote console in the VRM portal I can see the MPPT Charger via the Venus's Ethernet connection (which I would take to mean the VE.direct comms from Venus GX to the MPPT charger are good):


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It looks like the charge voltage is being set correctly by the BMS:


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I can not edit the values from this screen, and would normally expect to be able to from the Victron connect app, but the MPPT Charger is not listed as a device connected when I view this site:


1677891480599.png


Any ideas why The Venus GX would list the Charger, and its firmware, Serial number etc, but I would be unable to edit its settings via Victron Connect?


Thanks


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12 comments
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JohnC avatar image JohnC ♦ commented ·

@Technology

Try using the Remote method (VC-R). You select VRM rather than Local.. https://www.victronenergy.com/media/pg/VictronConnect_Manual/en/victronconnect-remote--vc-r----configuration-and-monitoring-via-vrm.html

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technology avatar image technology JohnC ♦ commented ·

Hi John,


That gives the same result I'm afraid. VRM > *The site in question* > devices: No devices listed at all.

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JohnC avatar image JohnC ♦ technology commented ·

@Technology

Do you get this screen?..

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VRM is selected (the thin red line under the blue), and VRM is ticked Online. When that CCGX selection is clicked it will load a list of the available devices on that installation, whether it's local or remote. This is with a WinPC.

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technology avatar image technology JohnC ♦ commented ·

I do get that screen, once I select the site, there are no devices listed:


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