Victron Quattro with BYD battery overcurrent failure

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fanda-eu asked Feb 3, '20

Victron Quattro with BYD battery overcurrent failure

Hello. Our system is Victron Quattro 8kVa with BYD L-box of 14kw and the SMA SB 5 kw solar inverter. The system is configured with Color Control/ ESS in the self consumption mode

The problem: Just before the SoC reaches 100%, the battery might disconnect with overcurrent error message, indicating about 32A in the error message. The battery will reconnect after 4-5 seconds. This occurs normally once per day. The problem can be reproduced when the SMA inverter output is about between 1 and 2 kW.

1. Is it possible to verify that the supplier has provided the correct firmware version for the BYD batteries ? It seem to be below what is recommended, but I might be mistaken

2. I've uploaded the video demonstrating a problem:

https://www.youtube.com/watch?v=HpnYdB5XaZI&feature=youtu.be

the system fails at the index 1:48 min

additional info:

the problem happens both in grid-connected mode and in the isolation mode

when it happens, the Quattro will enter "absorption" mode, and it seem to try maintaining the absorption voltage commanded by the battery, while no longer respecting the charging current indicated by the battery.

Any assistance is appreciated

Best regards,

Oleksiy Frolov

BYD victron

20200203-214141.jpg (6.3 MiB)

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Answer 1 · 2020-02-04T07:22:49Z

byd-service answered · Feb 04, 2020 at 07:22 AM

Hello Oleksi,

The battery must be update to software version 1.4 or above during installation. This should solve the issue. The problem is that the battery requires the inverter to reduce current to 0, the inverter can reduce it but not completely to 0 so it triggers the alarm. Software version 1.4 and above have relaxed the overcurrent protection in these circumstances.

Please download the file from https://www.eft-systems.de/en/downloads

There is a small text document with the explanation, also you can check step 13 in the quick installation guider provided with the BCU or the youtube video below.

https://youtu.be/CDigZKhu6Qg

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fanda-eu commented · Feb 06, 2020 at 12:32 AM

fanda_eu answered · 7 hours ago

Hello. Upgrading the firmware has helped to prevent the battery disconnect in the grid-connected mode:

https://youtu.be/u24rifSMmJo

However, when operating in the off-grid mode (simulating the power grid failure), the Victron takes a very long time to beging shifting the frequency in order to reduce the PV power (takes about 8 seconds for the victron to begin the frequency shift, after the 0 charging current limit is indicated), resulting in the battery disconnect:

https://youtu.be/GH-45ptBAvk

Which interesting enough, was working fine in this mode with the version 1.2 of the BYD, since the maximum charge current, as commanded by the battery was reducing slower than with the 1.5 version.

The equipment firmware versions are:

Color Control v2.42
BYD v1.5
Victron Quattro v469

The ESS assistant frequecy shift is set as recommended in this forum for the SMA SB inverter:

Freq 51.0 51.9 52.5

Any suggestions ?

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fanda-eu fanda-eu commented · Feb 06, 2020 at 08:06 PM

Could the "charge current control assistant" be used to keep the charging current down during the last % of the battery SoC (I believe it can be approx seen by the voltage of the battery). Would the Victron apply the minimum of the BMS current and the "charge control assistant" limit ?

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Answer 2

fanda_eu answered · 7 hours ago

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