How to configure max charge % #2126
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Apologies for the half-written title, I can't edit it. This is a 'how do I configure' type of question. Two interlinked queries - firstly, ideally I don't want the battery going over 90% when either charging overnight, or receiving PV during the day, instead I'd prefer PV to be exported. There is a flat export rate, and it is a big battery, so there is no point in storing PV if the battery is already full enough for the rest of the day. Are there settings to do that? Is there a way to reserve the top 10% of the SoC range so that it won't be used by PV or by the overnight charge? Also, it seems to be randomly flicking between the two modes, immediate PV export, or store in the battery for later export. Presumably inverter writes are going up, and also it will be an efficiency loss & unnecessary battery cycles from storing it locally. Hopefully if it knows the top 10% is reserved, it'll just export instead of storing the PV.
This is on a Fox inverter + battery system. Feed-in First is the mode where solar is first used for the house load, then used for export, then if the export limit is reached, to change the battery. Self-use is where the solar is used for the house load, then charging the battery, then if the battery is full + overflows, it is exported. I manually set it back to Feed-in First a few times. 'Supervisor' is when it is being set by predbat.
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Replies: 2 comments 3 replies
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I've edited the title for you 😉 Trying to answer your questions: Predbat doesn't really have a concept of 'reserve top X% and don't use it', it will charge the battery as much as is needed for the predicted future load. So saying that, if Predbat doesn't see that you need the PV generation stored then it will let it be exported rather than charging the battery unnecessarily. You could also look at setting soc_max in apps.yaml to a lower value but I suspect this will only take an effect when force charging the battery. For solar charging Predbat lets the inverter manage things. In terms of plan oscillation, this is probably due to the plan being quite tightly balanced as to whether its worth exporting or storing the PV. You could increase metric min improvement export to say 5p or higher to encourage it only to export if its financially worthwhile. I also find having the cloud model enabled can cause the plan to oscillate when PV50 and PV10 are not close together, so I turned the cloud model off to prevent this |
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Many thanks :-) Hypothetically, do you think it would be worth doing a feature-request to automatically always export solar for slots where the export rate is = the best export rate, and when the SoC is above some user defined limit, or does Trefor already have enough on his plate as it is? Currently it goes through the optimisation process to decide, but that just adds unpredictability. If it is a simple switch it gets rid of any plan oscillation ... It'd benefit people with flat rate export and batteries bigger than their typical usage. It wouldn't help people with other types of export tariff or smaller batteries who would need the optimisation functionality to figure out if the solar needs to be time-shifted. |
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Yes I think Trefor has enough on his plate already ! There are some longer term things like clipping and improved support for multiple inverter plans and preventing cross charging that I personally wish would get to the fore ...
But, there's no harm in adding a FR in. I'd suggest you keep it simple, if there are too many bits to the decision logic then it becomes hard for people to understand and quite niche.
A max soc % would be a simple concept, to stop charging the battery (solar or grid) when a specified percentage is reached would meet your needs, and would help with #1206 clipping as well as it could be dynamically changed