Multiplus II GX with ESS is stuck in float mode at 80-83% SOC

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daniel1976 asked Dec 9, '19

Multiplus II GX with ESS is stuck in float mode at 80-83% SOC

Hi Community,

I run ESS with Battery Life mode. I have set minimum SOC to 70%. After some days with little sunshine the active SOC limit is at 80%.

It alternates between discharging to 80% and charging in "float mode" and it charges very slowly even if there is a lot of PV power.

This way I am stuck between 80% and 83% SOC.

The lead battery voltage is at 51,6V (12,9V) which seems to correspond to 100% SOC.

So I assume that the battery is actually fully charged and the Multiplus GX battery monitor is just wrong currently. How can I get the battery monitor back to 100% ?

Thank you for your hints.

Best regards

Daniel

ESS

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Answer 1 · 2019-12-10T03:30:52Z

JohnC answered · Dec 10, 2019 at 03:30 AM

Hi Daniel.

If using the Multi's SOC, you can tune it within VE Config. In the General tab you'll see Battery Monitor. Maybe set 'State of charge when Bulk finished' to (say) 95%, even higher. This is a much coarser soc derivation than a fully-fledged BMV, but it suffices for many.

Maybe you're using your batts as a ups, rather than cycling them. So sure, it won't push high current in Float mode..

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Answer 2 · 2019-12-10T10:24:12Z

daniel1976 answered · Dec 10, 2019 at 10:24 AM

Hi John,

thank you. Yes, I am cycling. The issue seems to be that currently the SOC is only 76% but the actual battery voltage causes the Multi to run in Float mode (54.2 V and 9A in this moment)

This way, getting the SOC display back to 100% will take a while...

Maybe the only way is to modify the VEConfig Battery Monitor settings as you mention:

Shouldn't setting the battery capacity temporarily to a very low Ah value help to get the SOC number climbing very quickly ?

Thanks

Daniel

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JohnC ♦ commented · Dec 10, 2019 at 11:17 AM

Yeh, little point 'temporarily' doing anything. If you really want to use SOC, no point mucking about, it'll likely drift anyway without regular 'syncs'. I don't bother with soc personally, but that's just me. Tis a calculated figure, and if to be useful needs to be set up correctly. No shortcuts in the literature. :)

Sorry, but your figures don't mean much without knowing your whole system specs. I consider my Pb's 100% when in 55.2V float, and the charge A is ~1% of total batt Ah (after consideration of loads).

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