question

Vangelis Beligiannis avatar image

BYD LVS High voltage warning on Remote console

I have an offgrid system with a Quatrro 48/8000, MPPT 150/70 and Fronius Primo 5.0 on the AC output.

Charging parameters for the Quattro and the MPPT are entered as the victon-byd instructions demand.

The strange thing is that I receive High Voltage warnings from the BYD BMS on my Remote console. Why is this happening? The BMS is only responsible for the charge algorithm so why does it create warnings for High voltage?

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BYD
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Hi,
I got the same problem with a Quattro 48/8000/110, 2 x Smart solar VE.Can 150/70 MPPT's and BYD LVS batteries. All the devices are updated with the latest firmware and all the setting seems ok. But this warnings are happening every afternoon when batteries are getting fully charged by the MPPT's.


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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Vangelis Beligiannis,

While not ideal, these are only warnings, and the system is recovering before it shuts down in 'Alarm'.

The messages are coming from the BMS, which is connected to the battery, and then communicated to you via the GX device.

Hopefully they are rare and intermittent, and most likely due to a change of solar or load conditions when the battery is approaching the very top of its charge cycle (and most vulnerable to an overshoot).

There is probably not much to be done about them for now, take note to see if they are increasing in frequency - which then would be cause for further action. Hopefully the opposite occurs, and they are becoming less frequent, which indicates that internal cell balancing of the BYD is improving (and able to take more current without spiking individual cells at the top end of the charge cycle).

If you have a grid connection available, you could try to hold the battery voltage at fully charged for as long as possible, as this will also help improve the cell balancing (but can take dozens of hours at 100%).

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Thank you for your reply. I tried to do the charge with the grid connected and the voltage reached 57Volts with no alarm! This is strange because without the grid the alarm pops up at 56.6 Volts.
Nicolás M. Zunino avatar image
Nicolás M. Zunino answered ·

Thank you Guy for your very quick reply. For now I will mute the sounder and just be patient. Also be checking the system closely to see what happens.

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yaute avatar image
yaute answered ·

Hi,
I'm facing the same problem on both architecture, ESS and off-grid. The installation uses a MPPT RS 450/100 and a BYD LVS runing on the last firmware. As soon as the batteries rich the float level I get a warning per minute. I will appreciate if VE reports this point to BYD.
Cheers

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@Yaute

Check on your individual cell voltages, sometimes the high voltage warnings are reported when there is a larger deviation between the highest and lowest cell. So it is cell balancing related.

yaute avatar image yaute Alexandra ♦ ·

Hi Alexandra,

You have right during the warning phase The BYD the minimum cell voltage is 3.36V and the maximum is around 3.75V. I hope the BMS is cleaver enough to balance them...

Cheers

igee7 avatar image
igee7 answered ·

Same problem here: I run an ESS system with 3x MP-II and a BYD LVS 16.0 kWh ... when using default charge voltage limit as it comes from the BMS (58.4V) I'm getting overvoltage warnings as soon as the battery is reaching full charge.

Individual cell voltage is peaking to 3.75V (as I know LFP should never be charged to more that 3.65). Lowest cell voltage is about 3.36V. So I'm wondering why the BMS is not balancing anything. And it always happens on the same module...

At the moment I limited CVL to 54.6V so this does not happen any more. When reaching 0 A tail current cell voltage deviaton is still at >250mV and the battery is floating at around 98% SOC.... So I guess a least one of the cells are having some kind of problem. The battery is less than 6 month old...

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