Multi RS Solar - PV power requires battery to be charged to also return to grid

DIY
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I’ve the Multi RS Solar installed with a battery and solar panels. For testing reasons the battery is set to max 30A for charging and discharging. When the PV power is above the max charging power, the JK-BMS send message to Multi RS Solar that the current is to high, which is correct as per configuration. Why is the Multi RS Solar not returning the extra PV power not directly to the grid?

I would expect that the battery is charged with max 30A as per config and all the extra PV power is returned directly to the grid. This is not the way how it works currently. After the JK BMS sends the error message, high current, the Multi RS is set into passthrough mode and there is NO PV power coming in anymore.

I do not have any load on the AC1 out. Could that be the reason?

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This is what I’m getting when the Multi RS is switched to ON (including charing and inverting). Good thing it is returning PV power to the grid. But it is not charging at the configured 30A.

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Maybe I was jumping to conclusions to soon, looks like it is working now. 30A from PV power to charged the battery and the rest returned to the grid.

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What changed that’s working now besides the ESS#3 is not present anymore ?..

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Good question, to be honest I don’t know.
Initially I had the Mutli RS set to “Charge only” and later changed it to “On” (so also inverting). That was already the case in the first picture, in which the battery was not charged.

Maybe the system needs time to measure and finally configure how to operate.

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I have a similar behavior with MultiPlus II+RS450+MPPTs+Pylontech setting, so it seems to be part of the VenusOS:

When I have a DC charge-current limit set as well as a maximum DC voltage, both to preserve batteries which have quite agressive limits, and battery gets almost full (typically around 95% and the BMS starts lowering charging current), the RS450+MPPTs are limited in their power first, instead of the MultiPlus being instructed to feed the excess to grid.

This state goes on for up to several dozens of minutes, before the VenusOS “mode” or “mood” changes, and then it suddenly unlimits the RS450+MPPTs and the MultiPluses feed-in.

I’m wondering if this has not to do with “all-or-nothing” “mode”-based algorithms around the current and voltage limits, that thus do not behave progressively.

I’ve reported several times this issue in the old forums, without success. May the power of the new forum be with us this time! :slight_smile:

In my case, that means daily losses of PV power sales to grid.

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