Do not reach 100% SoC on solar but on AC yes?

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Herve RV Nizard asked Aug 18, '22

Do not reach 100% SoC on solar but on AC yes?

One of our systems is behaving strangely.

This is a test system.

2 x 410w panels on 100/20

2x445 w panels on 100/20

440ah agm Northstar bat in 4s2p (12/210)

Multi 48/3000

Smart shunt - Octo gx

We never come back to 100% soc from solar.

We would have far enough sun to.

Seems to go easily to 96/98% but looks like goes too early on float. Hardly reaches absorb voltage.

When we remove VS settings and let the charge from AC ( at only 10 a dc), easily goes to 100%.

Any idea why wouln't it reach 100% from solar but would from AC ? both have exact same settings.

Smart shunt has been reset to 100% when it reached there.

MPPT Controllers SOC

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screenshot-20220818-172150-vrm.jpg (224.6 KiB)

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Modifications Space

Node Red Space

Answer 1 · 2022-08-19T01:20:07Z

snoobler answered · Aug 19, 2022 at 01:20 AM

What are your smart shunt sync parameters?

Are your 100/20 smart and in a VE.Smart network coordinating with one another? Is the smartshunt part of it?

What are your "exact same settings?" MPPT can specify a tail current, AC charger can't.

If your MPPT aren't coordinating, it's very common for one to drop to float as absorption is reached.

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Answer 2 · 2022-08-19T01:43:12Z

johanndo answered · Aug 19, 2022 at 01:43 AM

Your MPPT quits too early, increase the absorption voltage setting, you have too much voltage drop between MPPT and battery, too thin cables, circuit breakers or whatever.

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Answer 3 · 2022-08-19T02:44:29Z

kevgermany answered · Aug 19, 2022 at 02:44 AM

Looks like you have a mismatch between the shunt settings, MPPT settings and multi settings. Also the MPPT is mostly in bulk, which may mean inadequate solar. Looks as if the AC load is overpowering solar output and being supplemented by battery.

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