question

vicky avatar image
vicky asked

Too early cutoff when load is low

During years we optimized pwr consumption of our home, idle mode at night is around 250W-350W ish. Last night was the first our new Multigrid / LG RESU 6.5 combo was running the home by battery. Nice feeling btw.
However although minimum SOC is set to 20% system switched back from inverter to grid at 49% SOC.
My first guess - this is related to the cutoff voltage which is relatively high for small loads. If so how can I change this behavior?

ESSmultigrid
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi, Lower the low voltage cutoff values.

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vicky avatar image vicky commented ·

Txs for confirming, to better understand sensitivity of parameters I'll try now

0.005 C= 50.80 V

0.25 C= 49.90 V

0.7 C= 49.20 V

2 C= 48.00 V

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boekel avatar image boekel ♦ vicky commented ·

With a BMS controlled system I normally use the same value as inverter low voltage shutdown (and that at minimum voltage the battery or inverter can handle)

In these lithium systems the bms usually knows best. this setting I see as Lead-Acid battery values.

(please consider I didn't actually study the LG-Resu batteries, so if the manual says a different setting is needed please do that)

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vicky avatar image vicky boekel ♦ commented ·

I had used the LG RESU 6.5 settings outlined here at first, but obviously they need fine tuning.
I hope (expect) the LG BMS, which is integrated into the pattery pack, will ensure the battery health is managed well, independed of my settings.
Would be great to exchange settings and experience amongst LG battery users, but I didn't "meet" a lot yet.. ;o)

-1 Like -1 ·

I have updated the LG manual settings page with some further explanation and some much more aggressive settings for deeper discharge cycles.

Please let me know how your settings above perform and I may use them instead.

The down side of experimenting with the LG is it trips a breaker, and requires a physical action to reset.

1 Like 1 ·
vicky avatar image vicky Guy Stewart (Victron Community Manager) ♦♦ commented ·

My parameters weren't agressive enough obviously, inverter shut off at 29%, so I'll try your settings next


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vicky avatar image vicky Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi Guy,

I can confirm the flat cutoff settings work for me.

Thanks

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vicky avatar image vicky vicky commented ·

voltage and amps until inverter stopped

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vicky avatar image vicky Guy Stewart (Victron Community Manager) ♦♦ commented ·

Txs Guy, no sun these days, so I'll charge the battery and see how it behaves tonight. Breaker tripping is no problem, climbing all the stairs up and down keeps me heathy ;o)

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