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lawrence-1 avatar image
lawrence-1 asked

Abnormal low voltage alarm on Quattro

Dear all,

I have a 3-phase off-grid system of 3x5kVA Quattros running on firmware version 494 and Pylontech hub of 4x8 US2000.

The inverter settings are 44V for cut-off, 48V for both pre-alarm and restart. A genset is configured via Cerbo GX to start at 8% and stop at 15% SOC. This worked well for weeks but things changed when we started experiencing low battery alarm on the inverter at 18% SOC (which is about 47.2V), way before the DG could start at 8%. What could be the cause ladies and gentlemen?

MultiPlus Quattro Inverter Charger
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2 Answers
nickdb avatar image
nickdb answered ·

Right ladies, let’s polish the crystal ball..

Sorry Lawrence, way more detail is needed about your configuration - settings, loads, wiring etc.

Have you checked the bms for alerts as well?

Is this just the generic battery warning of the inverter or is there an actual problem?

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lawrence-1 avatar image lawrence-1 commented ·
Nickdb,

No BMS alerts.

Yes a generic low battery alarm on the inverter,

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Alexandra avatar image
Alexandra answered ·

@Lawrence

Have you set all dynamic cut off in ESS assistant to 46v?

Also it is probably a battery bank imbalance. How often does it get to full charge/absorption?

And as Nickb said, we need more information. Just guessing and fishing here.


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lawrence-1 avatar image lawrence-1 commented ·

Thanks Nickb and Alex.

Attaching configuration file for reference with a couple of changes to try solving the issue.

https://epge-my.sharepoint.com/:u:/p/dkeya/EZ6cb-K5KDlEpVWQp4JUY5QBUYMdOEv1nlwASWQe859tOw?e=mgkNQE

No ESS assistants configured.

The batteries get to 100% fairly everyday.

This is a community minigrid with peak hours in the evenings at between 8 and 12kW. However, we do have another old system feeding via AC IN1 to assist during peak hours and keep the load at 8kW max. The low battery alarm occurs around dawn during which load is between 4 to 5kW.

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