Multi RS Solar ESS feeds PV to grid instead of charging

DIY
, , , , ,
1

I have a single Multi RS Solar with a BMS NG and both MPPTs used.

For the winter I switched DESS off (in VRM and in GX) and use ESS.

I have set a Schedule Charging Schedule from 11h to 15h to 80%

I set the AC current to max 6A.

The system charges with 6A, fine.

If there is solar, it charges more, fine.

Reaching 80%, it stops charging from grid, fine.

After that point, it feeds all PV to the grid. Not fine. Per the docs, it should charge.

When the feed-in exceeds 6A, it starts charging with what is left over.

As you can see below, the Solar is roughly split between Grid and Battery.

IMG_5226
IMG_52263179×1787 1.02 MB

I believe this to be a bug. Can anyone confirm? Or isn’t it?

2

Id guess the PV power is split between battery and grid since the grid current is hitting the 6A limit. So any leftover is charging the battery. And by chance thats roughly 50/50. So whats your gridsetpoint set to? If you set that to -2000W for example, it will always feed back to grid up to those 6A grid current limit.

Whats the charging shedule for, do you have cheap power in that window?

3

Yes, it is 50/50 by chance. At first I thought everything was fed in until there was more solar.

Grid setpoint is 0W.

During those hours power is very cheap. Hence feeding makes no sense.

The documentation for the Multi RS Solar states for “Optimized without BatteryLife”: “when there is enough solar power to satisfy the loads, then the excess solar power will be used to charge the battery.”

Since there is no statement in the ESS-section that this would reverse (which would be very odd), I assume it remains true (which is logical).

Any suggestions?

4

Is feed-in enabled? If so, have you tried reducing the limit and does it respond?

5

Yes, feed-in is enabled. This is an otherwise perfectly working system.

Reducing the current limit is the only way to let it charge the battery when there is solar. So I set it to 0 and later put it back to 6 or 10 A.

Could it have to do with left-over settings from DESS which was enabled previously? (Then still a bug of course).

6

Possibly. If you disable or limit feed-in, does it behave?
What version is your GX?

7

Hmm, disabling feed-in. A provoking question. Makes me think. Perhaps I should find the places where feed-in can be disabled and toggle them all once. Could give a hint of where the problem can be.

GX is latest version: v3.85. I might as well try rebooting; it is a computer after all…

Tomorrow I will try, when there is solar.

8

When weird issues persist, and since you mentioned DESS, if all else fails, sometimes following the cerbo factory reset procedure (used to be chapter 9 iirc, but don’t hold me to it) is also a useful step to rule out a latent problem.

9

I will be very reluctant to do that since there is no proper configuration management (I am aware of), I must reconfigure everything by hand, which is error-prone and time-consuming. I am afraid it will only take me further down the rabbit hole of not knowing which setting to touch & being unsure if settings work properly. So, yeah, really a last, last resort. (And I will be forever masking the bug of course.) This is my personal system, but I wouldn’t even think about doing that one other’s systems…