Disabling charging during time period

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davebaldwin asked Oct 12, '23

Disabling charging during time period

I have a multiples 2-5000 with pylontech batteries and separate AC coupled solar array. I want to just charge the batteries during my off peak tariff and not when solar is being generated during the day. I am on Intelligent Octopus (7.5 off peak kWh) and their Outgoing Octopus export (15p/kWh) so I want to export any excess solar power after what the house uses and not use it to charge the batteries. None of the house power comes from the dedicated multiples AC outputs so I cannot do much about the house using solar power without a big rewire of the consumer units. I still want the batteries to run the house when solar is insufficient.

I have two charging schedules set up:

1. Start time of 23:30 and duration of 6 hours, SOC limit of 100%.

2. Start time of 05:30 and duration of 18 hours, SOC limit of 5% and self consumption set to PV&Battery.

I have just added the second schedule and it isn't working, i.e. charging is still occurring from solar when the batteries are 90% SOC so I don't understand why.

I believe I am on the latest firmware.

I have had a brief look at ESS mode 2 and it looks like this may be an alternative from MQTT but I would prefer not to have to go down this route.

Any help or guidance on how to stop the batteries charging during peak hours appreciated.

Dave.

Multiplus-II battery charging

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Answer 1 · 2023-10-13T17:46:43Z

Alexandra answered · Oct 13, 2023 at 05:46 PM

@davebaldwin

maybe the Dynamic ESS in beta would interest you.

There is also the webinar on YouTube if you want to know more before digging in there.

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Answer 2 · 2023-10-15T11:17:03Z

davebaldwin answered · Oct 15, 2023 at 11:17 AM

Thanks Alexandra. I looked at the Dynamic ESS but didn't see anything in there that would allow me to do the rather simple thing I wanted. It is something I will consider if I lose this favourable tariff.

The solution I ended up with was to use Node Red to switch the Multiplus between Inverter and Charger modes between set times. Victron have a similar example on their Node Red examples page that I based my flow on. This was my first encounter with Node Red and it was rather easy to setup and use.

Dave.

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Answer 3 · 2023-10-19T12:52:06Z

It turns out this didn't work as expected - when the Multiplus was in invert mode it wasn't powering the house and instead grid power was being used, even when the batteries were full. Maybe because the house loads were on AC-in and not on AC-out?

I have fixed this by setting the charge current limit to 0 during peak times and to 100A during off-peak times.

My flow is as follows with peak times from 0530 to 2330.

Dave.

[{"id":"195f739c5ddc2f80","type":"tab","label":"Disable charging during peak times","disabled":false,"info":"","env":[]},{"id":"1898bb04.622815","type":"rbe","z":"195f739c5ddc2f80","name":"","func":"rbe","gap":"","start":"","inout":"out","septopics":true,"property":"payload","topi":"topic","x":650,"y":240,"wires":[["7180d1e17c4c16c8"]]},{"id":"1b5620693c2b25d8","type":"inject","z":"195f739c5ddc2f80","name":"","props":[{"p":"payload"}],"repeat":"60","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"go","payloadType":"str","x":310,"y":240,"wires":[["26dccad281c3ed40"]]},{"id":"26dccad281c3ed40","type":"function","z":"195f739c5ddc2f80","name":"peak time?","func":"// get current minutes past midnight.\nconst mins = new Date().getHours() * 60 + new Date().getMinutes()\n\n// Trigger a message if the time is between 5:30 and 23:30 or the peak times\nif (mins >= 5 * 60 + 30 && mins <= 23 * 60 + 30)\n msg.payload = 0 // peak electricity, set max charging current to 0\nelse\n msg.payload = 100 // peak electricity, set max charging current to 100A\n\nreturn msg","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":470,"y":240,"wires":[["1898bb04.622815"]]},{"id":"7180d1e17c4c16c8","type":"victron-output-ess","z":"195f739c5ddc2f80","service":"com.victronenergy.settings","path":"/Settings/SystemSetup/MaxChargeCurrent","serviceObj":{"service":"com.victronenergy.settings","name":"Venus settings"},"pathObj":{"path":"/Settings/SystemSetup/MaxChargeCurrent","type":"float","name":"Charge current limit (A)","writable":true},"name":"","onlyChanges":false,"x":920,"y":240,"wires":[]}]

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