I’m running my system in ESS mode at the moment. Battery is full, there is solar energy being generated and I expect that this is returned to the grid. Why suddenly is the system discharging the battery? I would expect the battery to stay in idle mode until there is power required which cannot be delivered by solar energy. Any suggestions why this is happening?
Another strange ESS behaviour, in my view. There is enough solar power, the battery is being charged but still power from grid is being pulled. Why?
Tell us more about your settings. About assistants installed.
What do you mean with “assistants”?
Running in ESS mode. DESS is switched off. Multi RS Solar with Gerbo GX and two JK-BMS V15 with EVE 318Ah batteries. There are two MPPT’s in the setup but no solar pannels connected yet. What other information do you need/can I share?
Another strange behaviour, at lease in my view. Could be due to a misconfiguration of course, if so, what to change?
I scheduled a grid charging schedule in the Multi RS Solar → ESS → Scheduled charge levels and of course at the time it starts charging from grid. But the solar generation was reduced, not taken into account when charging the battery. Why not? I expect that the solar generation is always taken into account when the battery is charged and on top of that the grid is being used to maximise the charging power.
When I disable the charging schedule, suddenly the solar power is increased to a much higher value, see screenshot:
@dognose when you have time, can you check this situation? Is this a config issue or a defect in the system? I’ve just upgraded to version V1.24 (Multi RS) and v3.60~85 (Gerbo). VRM ID: 724294.
Thx for sharing that. This is not directly DESS related, but I will forward it to be looked at.
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Thanks @dognose for looking into this.
For clarity, and I hope my expectation is correct and this is the way how it should work. When a charging schedule kicks in to charge the batteries from grid, still all available solar power needs to be used to charge the batteries as well.
My current observations is that as soon as the charging from grid is started, the solar power is reduced. When I stop the charging from grid the solar power increases again. So this is not a cloud that is in the way and reduces the solar power!
Let me know if you require additional information or if you want me to test something. Thanks for the support.
@dognose Another example of this issue, solar generation reduced when charging battery from grid.
Screenshots are taken within 30 sec or so from each other. On the left the charging from grid enabled, solar generation 1453W, the picture on the right, solar charging from grid disabled, solar generation increased to 2269W (about 1kW difference!).
As for the first scenario (discharging to grid) , I had this too in the past. I think this is because, when the batteries are full, the system changes to float which most likely has a (much) lower voltage and the system start discharging the battery at this point till the float voltage is reached. You can reduce this by setting the float voltage closer to the absorption voltage.
For the reduced mppt charging during grid charging. Have you enabled in ess settings; allow DC-coupled pv - feed in excess? if not try this.
Interesting suggestion, thanks. I’m running a Multi RS Solar. My ESS config options are very limited, I cannot find the DC-coupled PV option!
I found another discussion ongoing which is probably exactly the same as I’m experiencing:
Same as I described earlier, btw this is not related to the JK BMS CAN-bus set up as I had this issue too with my previous Lifepo4 batteries which could not communicate with my gx device. For my current set up with 2 x jk bms and CAN bus my charge settings (jk bms master) is Cell rcv: 3.45 V and Cell RF: 3.375 Volt, this brings the max charge voltage to 55.2 Volt and the rest/float voltage to 54.0 Volt. This works smoothly in my set-up.
Thanks @bartG for your feedback and support. This is for the discharging when the battery is full, correct? Your suggestion is to configure the floating voltage in the JK BMS to 3.375V, correct?
For the reduced PV/Solar power when the charging from grid (schedule) is enabled, for this there is no suggestion yet on how to address this, correct?