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Help Diagnosing 12V Parallel Valence U27-12XP Bank


New Member
Mar 8, 2024
I have some questions about a 12V battery bank on my new to me boat. It consists of four Valence U27-12XP batteries that were wired in parallel without an external BMS, but voltage-disconnect protected by a Victron Battery Protect device. I've removed the batteries for testing at home. The LED behavior I am describing was occuring before I disconnected them.

Two of the batteries seem to be fairly happy (with a five second green flash and minimal voltage variability) and good states of charge. I plan on reusing these two.

One (that I'm addressing here) is flashing red every 5 seconds and I've retrieved the attached screenshot using the Valence software and cable. I'm guessing that the red flash is due to the intercell variability (lower voltage) on #4? Is there a way to try and rectify this besides the 12 hours of sit at open circuit and then charge it? If I cannot get the flashing red to go away, is this safe to hook back up with the other two and use in parallel as is?

Finally, the fourth battery is showing a steady red LED. I cannot find an interpretation for this online, and the software has been unable to locate the battery when I plug the USB-RS connector in. I'm assuming that this means that this battery is toast (maybe due to the failure of the internal BMS/circuits) and that this one cannot be reused...?

I'd appreciate your thoughts.


  • Valence Flashing Red.PNG
    Valence Flashing Red.PNG
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    Valence Page 2.PNG
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    Valence Page 3.PNG
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Found the answer in a owners manual I was able to download from here:

Steady red means "This indicates that the module onboard electronics is not functioning, and the processor has stopped. If a module exhibits this behavior,, please contact Valence Technical Support Staff immediately to determine battery recoverable. Do not attempt to charge or discharge!"

Considerably worse than the flashing red which means "A red blinking LED indicates that the recommended limits for normal operation have been exceeded.

If the LED indicator blinks RED, one of the following has occurred:
• Over temperature alarm i.e. cell temperature is > 65°C or Internal electronics temperature > 100°C
• Overcharge alarm i.e. Cell voltage is >4.0V.
• Over discharge alarm i.e. Cell voltage is < 2.3V and will not rise above 2.3V after charge current >
0.5Amp for 1 minute.

For the overcharge and over-temperature alarms, the red light will remain latched, even when the condition
for the alarm no longer exists. For the over discharged alarm the LED will be reset, i.e. go to green, if all the
module cell voltages are charged back above 3.3V.

Should a module exhibit a red flashing LED, please contact Valence Technical Support Staff immediately for
help to determine if the battery is recoverable. Do not attempt to charge or discharge!"

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