Dyness batteries discharge cutoff at 30-40% SOC

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enfrafer asked Feb 6, '23

Dyness batteries discharge cutoff at 30-40% SOC

I am looking to find the root cause of the early cutoff of my Dyness batteries discharge every day.

My recent (Dec '22) installation has a system configuration that includes:-

- A Fronius with a string of solar panels

- A Victron (Multiplus + Cerbo + mppt) with a second string of solar panels

- 2 batteries (dyness A48100, 5 Kwh each)

Every morning, when batteries SOC is under 40% and home loads peaks reach 3-4 Kw (e.g. microwave, coffee machine and kettle or toaster) I get a low voltage alarm (< 46 V) and the battery gets idle for a while.

The installation shows a few things that I do not fully understand and might be related:

- The batteries seems not to discharge at the same speed. In fact, this morning just after the alarm showed up again, the main battery was under 20% and the second under 60% SOC.

- The BMS and Dyness on VRM dashboard shows completely different instant battery discharge values. BMS might be showing like - 2500 W while Dyness shows - 800 W.

VRM Dashboard Enrique.jpg

ESS battery capacity

vrm-dashboard-enrique.jpg (1.4 MiB)

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bcollinson7 commented · Jan 18 at 06:15 PM

I have the same problem.

Installed July 2022. OK till 3 months ago.

Cuts off at 40% and low voltage alarm goes off. All 4 batteries have same fault

.have solar and growatt inverter.

Anyone got a solution to this?

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Answer 1 · 2023-02-06T16:06:02Z

Bonhardt László answered · Feb 06, 2023 at 04:06 PM

- The batteries seems not to discharge at the same speed. In fact, this morning just after the alarm showed up again, the main battery was under 20% and the second under 60% SOC.

could be related to how are the 2 battery parallel wired to each other or the 2 battery never had a chance to balance between as it is never reached enough high voltage.

The BMS and Dyness on VRM dashboard shows completely different instant battery discharge values. BMS might be showing like - 2500 W while Dyness shows - 800 W.

sounds like the communication between the 2 battery is not working, maybe the dip switches on the batterys are not configured properly so you are getting only data from the master pack

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enfrafer commented · Apr 18, 2023 at 06:04 AM

Dear @Bonhardt László, I finally solved the issue with the batteries. In fact my second battery stopped working. The installer reviewed the wiring and it had burnt. There was a nut not tightened properly. In addition they upgraded the Victron SW. Now the system seems to work fine with no alarms. Thank you!

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Answer 2 · 2023-03-23T08:36:19Z

enfrafer answered · Mar 23, 2023 at 08:36 AM

Coming back after some changes. The slave battery that was not properly discharging is being replaced by Dyness. In the meantime, I am trying to review how the system works now with only one battery. And I still see that on VRM, the BMS and the own battery monitor show quite different values. The one from the battery seems to be okay, but the instant current and power on the BMS show quite lower values (see screentshot).

Is there any configuration that can be used to align both?

VRM Diff BMS 1.png VRM Diff BMS 2.png

vrm-diff-bms-1.png (155.8 KiB)

vrm-diff-bms-2.png (111.5 KiB)

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