question

Talfan Stamps avatar image
Talfan Stamps asked

BYD Overvoltage MPPT shutdown

Hi all

Strange occurrence, GX alarm battery Overvoltage at 55.1V with BYD batteries.

8kVA

RS 450/100 MPPT, tracker 1: 5 x Longi 450Watt (231V) tracker 2: 8 x Longi 450Watt (381V) It's within minimum spec for Float V of 52.5V

BYD comms working on GX (BYD shutsdown if comms aren't working)

BYD is supposed to control both MPPT and inverter for charging, but I set up charge tab to 54bulk and 52.5 float in any case. Battery monitor is on, at 400Ah, 98% and 0.99 efficiency.

What seems to be happening is that when generator is on, AC2 input, and the battery reaches 100%, the voltage climbs beyond 54V over to 55.2 is highest I saw with incessant alarms.


Switching off gen input seems to stop the problem, but no AC mains was available to test during this phenomenon, and solar yield had dropped too low to test with it.


MPPT shutdown on overvoltage, error #29.


What I don't understand is why BYD didn't control the situation as it is supposed to......






Lithium BatteryBMSovervoltagemppt rs
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3 Answers
Talfan Stamps avatar image
Talfan Stamps answered ·

Also:

MPPT set up to 53.5V bulk and 52.5V float.


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mysik avatar image
mysik answered ·

Did you turn on DVCC on the Victron GX? This is required to allow BYD BMS to control mppt and inverter

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Talfan Stamps avatar image Talfan Stamps commented ·
yes


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Alexandra avatar image
Alexandra answered ·

We have found with the BYD you need to limit the charge voltages in DVCC as well to 55.2v so make sure it is on as @Mysik mentioned.

BYD recommend different voltage to the one you are using.

https://www.victronenergy.com/live/battery_compatibility:byd_b-box#veconfigure_settings


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Talfan Stamps avatar image Talfan Stamps commented ·
Thanks, DVCC is forced on by BYD, but I have done as you said. I know my voltages are low in VE Config and MPPT, but I set them there intending to eliminate this problem, and it did not work. I've also been getting #35 errors. I've just updated the RS firmware to 1.10 as advised, and will see if the problem clears. If not then we have a faulty RS MPPT. Incidentally, whether linked or not, the GX touch did not work from second 1. It was white, blank, and the GX cerbo would not allow access to itself for configuration. Both were replaced under warranty. Up to this point mains power, solar power, and gen power had not been switched on, just running off BYD, which were staying on, implying successful communication with GX. After replacement there were no issues with them, only the main above issues as mentioned.
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