[Feature]: Make a difference between DC and AC connected solar with regard to battery costs

SimonYoungtree commented 9 months ago

Contact Details

siempoot@gmail.com

Description

The costs for using the battery are mainly (90%?) caused by using the Multiplus to convert from AC to DC and vice versa. I have both DC and AC grid-connected solar, so I can imagine that there are moments for which it would be smart to dump the AC generated energy straight to the grid, but at the same time charge the battery by using the DC capacity.

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Additional Context

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SimonYoungtree commented 9 months ago

I am happy to see that currently the system is charging the battery from DC only. Power from AC is going out to the GRID directly. So this has already been implemented?

SimonYoungtree commented 9 months ago

Is there any plan to consider the "battery" costs to charge from DC connected solar to be 0 (Zero)? I do not think DESS makes optimal use of this. The above remark seems to be a coincidence after having done further observations.

MichaKersloot commented 7 months ago

Not sure if I see the same. I only have DC connected PV and at this moment DESS decided to sell to the grid, while the batteries are at 45%. My battery-costs are set to 3 cents, but in the evening the prices are 7 to 8 cents higher than now. As losses in the batteries itself are almost nothing I'm don't understand why DESS decides to sell at this lower price and not charge the batteries and sell it at a higher price in the evening. The losses are virtually the same.

p.s VRM ID: c0619ab410ae

SimonYoungtree commented 7 months ago

I have "tricked" my system by setting the ESS discharge limit to zero between 10am and 4pm via Node Red. This way all DC connected solar energy is stored during that time window. The AC connected solar still follows the DESS rules. DESS does not seem to have a problem with this. After 4pm DESS accepts the SOC% as it is at that moment and incorporates it: no fierce discharging is taking place to return to some old plan.

MichaKersloot commented 7 months ago

Sounds like a neat trick.. where did you do this? I seem to be unable to find ESS discharging limit ;-) Hmm.. I see 'shed charge' instead of 'external control' so you disable DESS and enable the default ESS schedules?

SimonYoungtree commented 7 months ago

ESS Control Node: Venus settings : Max Inverter Power (W) can be set to zero or any value your inverters support. Of course this value, if not zero, should match the capacity mentioned in the DESS configuration (fb_max) I do not disable DESS.

MichaKersloot commented 5 months ago

As there is since long a sunny day. I noticed the charging power (W) really goes down when the battery gets full. Battery Parameters say: CVL: 53.2V, CCL: 40A, DCL: 160A Solar charger settings: Charge voltage 52.40V, Charge current 100A Current solar charging: Battery: Voltage 52.40V, Current: 5A (250W)

When I change the limit back from 0 to the 4100 I normaly have the Solar charger can produce a lot more power: Battery: 51.6V, 49A (2500W)

So this solution is limiting the yield from the system (a lot?)

dirkjanfaber commented 5 months ago

@MichaKersloot I do notice that you are not running the latest firmware right now. v3.20\~17 vs v3.20\~35. The older versions limited the solar chargers to prevent getting to the target too soon. Also noticing that your flow does not contain restriction fields. I suggest updating that too.

MichaKersloot commented 5 months ago

Hi @dirkjanfaber , thank you for your time. I did try the ~33 version, but had problems with the mqtt p1 connection: https://community.victronenergy.com/questions/244325/venus-os-v32027-available-for-testing.html?childToView=247950#comment-247950 is that solved in ~35 you think?

dirkjanfaber commented 5 months ago

There where some changes regarding the mqtt broker between \~33 and \~35, so it is worth a try:

dbus-flashmq, newest master https://github.com/victronenergy/dbus-flashmq
- Adds support for /Identifier to supplement /DeviceInstance in cases there is more than one of something.
- Fixes writing arrays as values, including null, which becomes an array.
- Fix dealing with signals that don't contain the values of paths
- Fix publishing all known item data on read/getvalue

MichaKersloot commented 5 months ago

Hi, i've just tried ~37 and there the p1mqqt got connected after a reboot of the esp device, but no data is updated. But mqtt explorer does show data:

MichaKersloot commented 3 months ago

Ok, today I was able to update (took the released 3.22 version). It seems there was a change in https://github.com/freakent/dbus-mqtt-devices needed and the new version of that solved my previously reported problem. I've also updated the node-red stuf and installed the most recent example flow. That one is now running without changes.

Long story short. I'm back for testing.

MichaKersloot commented 3 months ago

And here my first observations. No clue how the algorithm works, but it surely looks off.

For me it now looks like there are no losses in charging from the grid. Or the charging from PV are the same as charging from the grid... Aha ok. Back to disable charging from grid during the day I think.

P.s. Portal ID: c0619ab410ae

MichaKersloot commented 3 months ago

@SimonYoungtree how are you managing this now? Seems like the update to 3.22 broke the trick to set the inverter power to zero doesn't work anymore?

SimonYoungtree commented 3 months ago

I am at 3.30 and the "trick" is still working at my site.

Op zo 24 mrt. 2024 14:53 schreef Micha Kersloot @.***>:

@SimonYoungtree https://github.com/SimonYoungtree how are you managing this now? Seems like the update to 3.22 broke the trick to set the inverter power to zero doesn't work anymore?

— Reply to this email directly, view it on GitHub https://github.com/victronenergy/dynamic-ess/issues/60#issuecomment-2016817050, or unsubscribe https://github.com/notifications/unsubscribe-auth/BBFKQDF4QQVK6Y6Q5C6GCBLYZ3LFBAVCNFSM6AAAAAA4X2VKXSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDAMJWHAYTOMBVGA . You are receiving this because you were mentioned.Message ID: @.***>

MichaKersloot commented 2 months ago

I've altered the logic a bit to look at PV starts producing instead of time of day and have the current price lower than average.

[{"id":"8f445330606365fb","type":"victron-input-solarcharger","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","service":"com.victronenergy.solarcharger/273","path":"/Yield/Power","serviceObj":{"service":"com.victronenergy.solarcharger/273","name":"SmartSolar MPPT VE.Can 250/100 rev2"},"pathObj":{"path":"/Yield/Power","type":"float","name":"PV Power (W)"},"name":"","onlyChanges":false,"roundValues":"0","x":300,"y":1060,"wires":[["fd5ec03195b8a8be"]]},{"id":"fd5ec03195b8a8be","type":"rbe","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","name":"Filter small changes","func":"deadbandEq","gap":"5%","start":"","inout":"out","septopics":true,"property":"payload","topi":"topic","x":640,"y":1060,"wires":[["483b55b459ce6726"]]},{"id":"483b55b459ce6726","type":"join","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","name":"","mode":"custom","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","accumulate":true,"timeout":"","count":"2","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":230,"y":1140,"wires":[["1da48e45d5e34c2b"]]},{"id":"e8d7fd69dc16d657","type":"victron-input-battery","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","service":"com.victronenergy.battery/512","path":"/Soc","serviceObj":{"service":"com.victronenergy.battery/512","name":"Pylontech battery"},"pathObj":{"path":"/Soc","type":"float","name":"State of charge (%)"},"name":"","onlyChanges":true,"x":250,"y":1200,"wires":[["483b55b459ce6726"]]},{"id":"1da48e45d5e34c2b","type":"function","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","name":"Inverter settings","func":"let dess = flow.get('dess');\nlet date = new Date();\n\nvar PVPower = msg.payload[\"SmartSolar MPPT VE.Can 250/100 rev2 - PV Power (W)\"];\nvar BatSOC =  msg.payload[\"Pylontech battery - State of charge (%)\"]; \nvar lastValidUpdate = new Date(flow.get('lastValidUpdate')).toLocaleString();\nvar hour = date.getHours();\n\n\nfunction calculateAverage(array) {\n    var total = 0;\n    var count = 0;\n\n    array.forEach(function(item, index) {\n        total += item;\n        count++;\n    });\n\n    return total / count;\n}\n\nvar prices = Object.values(dess.output.p_s);\n\nvar priceavg = calculateAverage(prices);\nvar pricenow = prices.slice(hour, hour+1)[0];\nvar InverterPower = 4100;\n\n//node.warn ('price avg: ' + priceavg + '| price now: ' + pricenow )\n\nif (BatSOC < 93 && pricenow < priceavg) {\n    if (PVPower > 100) {\n        InverterPower = 0;\n    } else {\n        InverterPower = 4100;\n    }\n}\n\nnode.status({ fill: 'green', shape: 'dot', text: InverterPower + ' Pnow:' + parseFloat(pricenow).toFixed(2) + ' Pavg:' + parseFloat(priceavg).toFixed(2)});\n\nreturn { payload: InverterPower};","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":400,"y":1140,"wires":[["39bc68fea0f0a45d"]]},{"id":"39bc68fea0f0a45d","type":"rbe","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","name":"Pass changes only","func":"rbe","gap":"","start":"","inout":"out","septopics":true,"property":"payload","topi":"topic","x":630,"y":1140,"wires":[["b40ffb46a8af08bc"]]},{"id":"b40ffb46a8af08bc","type":"victron-output-ess","z":"5ec7274ba2dd58cb","g":"ea6da7c4489bd0ad","service":"com.victronenergy.settings","path":"/Settings/CGwacs/MaxDischargePower","serviceObj":{"service":"com.victronenergy.settings","name":"Venus settings"},"pathObj":{"path":"/Settings/CGwacs/MaxDischargePower","type":"integer","name":"Max inverter power (W)","writable":true},"initial":"","name":"","onlyChanges":false,"x":1000,"y":1140,"wires":[]}]

victronenergy / dynamic-ess