Disable MultiPlus 2 charger in summer days

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bernhards asked Apr 29, '24

Disable MultiPlus 2 charger in summer days

Scenario:

- Multiplus2 in ESS mode

- MPPT

- Cerbo GX

During sunny days, the battery is heavily loaded by the Multiplus2 which is not what I want. The solar modules of the MPPT are delivering enough energy during the day to load the battery so that the other PV inverter can feed in to the public grid and earn $.

In the Cerbo GX setting in the device Multiplus2 there is a setting 'switch' to set the device in inverting only but this does not really work - it stops charging but blocks inverting, too

Is this a bug of the CerboGX or only works without ESS? Is there another solution - which can be controlled via ModbusTCP later on?

I thought this is a standard scenario to get the most out of the devices.

Best regards

Bernhard

Multiplus-II cerbo gx battery charging MPPT SmartSolar Modbus TCP

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Answer 1 · 2024-04-29T06:58:29Z

nickdb answered · Apr 29 at 06:58 AM

In invert mode it won't charge and it does supply loads with the MPPT and Battery.

Grid is dropped so PV inverters can't backfeed.

Charger only mode, will passthrough grid power and will not invert, mppts will only be used for battery but PV inverters should still operate aiui.

Not sure if you got your modes confused, but that is definitely how it works.

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Answer 2 · 2024-04-29T07:49:30Z

floki answered · Apr 29 at 07:49 AM

Hello
Simply set the Cerbo GX under ESS->Limit charging power = switch on
and
Maximum charging power to 0 W

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nickdb ♦♦ commented · Apr 29 at 01:22 PM

Nope. That will also stop every MPPT from doing anything, including supplying loads.

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Answer 3 · 2024-04-29T09:34:18Z

duivert answered · Apr 29 at 09:34 AM

normally you dont have to worry about this, ESS will do that automatically

PV power > charge battery > surpluss house load > then grid feed in

and if batery full same: surpluss house load > then grid feed in

or am i misunderstanding your question?

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Answer 4 · 2024-04-29T10:49:53Z

bernhards answered · Apr 29 at 10:49 AM

Well, I want to charge the battery with the MPPTs only and let the Multiplus2 just run. The pv inverters are not connected on the Multiplus2.

Limit charging power would limit the MPPTs, too I guess?

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nickdb ♦♦ commented · Apr 29 at 01:22 PM

Yes it stops all DC generation.

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Answer 5 · 2024-04-29T11:22:18Z

duivert answered · Apr 29 at 11:22 AM

so you dont want the mppt's to deliver surplus to the grid?

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bernhards commented · Apr 29 at 11:39 AM

No. I only want that the MPPTs load the battery. Then they can just wait. Therefore I want, that the Multiplus2 doesn't load the battery so that the energy of the other AC PV inverters (hoymiles for example) will go into the grid. So the idea is, to have a loooong charging time of the MPPTs instead of getting the battery full in some hours because most of the energy is from Multiplus2 + the other AC PC inverters.

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Answer 6 · 2024-04-29T11:41:56Z

duivert answered · Apr 29 at 11:41 AM

ok,

have you tried scheduled charging? i used to use that for a charging "window" during daytime

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Answer 7 · 2024-04-29T12:13:55Z

mondeoman answered · Apr 29 at 12:13 PM

You could set the Grid Setpoint to a very large negative value, a bit larger than you AC PV power, e.g. set "-10000W" if you have 8 kW AC PV.

Then the MultiPlus 2 will not take power from the AC-IN to charge the battery, it will let the AC PV to export as much as possible.

Also make sure that "Export DC-coupled PV" is disabled in ESS Settings.

And when you want to re-enable charging from AC PV surplus, then set Grid Setpoint to a low value (e.g. 50W or whatever you normally use).

You could make a NodeRed flow on your GX Device to automate this setting based on the Forecasted PV energy for the day.

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Answer 8 · 2024-04-29T14:58:22Z

nickdb answered · Apr 29 at 02:58 PM

What about using node-red or MQTT to set /Device/DC/0/MaxChargeCurrent to 0 (if it is allowed) or a low value. This will allow the system to work as normal but prevent/limit AC charging.

IIRC it's the same parameter can be set via VC app or VEconfigure.

Not tried this myself, maybe it works.

screenshot-2024-04-29-at-165034.png (48.9 KiB)

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pwfarnell commented · Apr 29 at 04:26 PM

There was that discussion a month back about this setting not sticking because what you update is a live value in RAM not the saved setting and other processes such as DVCC could over write your setting from Node Red.

See

https://community.victronenergy.com/questions/271884/set-maxchargecurrent-to-0-within-node-red-works-bu.html

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nickdb ♦♦ pwfarnell commented · Apr 29 at 04:31 PM

I though as much as there is a "current" value that fluctuates, it is also not listed on the official register.

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bernhards commented · Apr 29 at 06:33 PM

MaxChargeCurrent would limit both, Multiplus2 (OK) and MPPT (NOK).

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nickdb ♦♦ bernhards commented · Apr 30 at 06:42 AM

Not necessarily this parameter which seems to be multi specific (it matches the limit set on the inverter itself) but as pointed out, it seems to vary under DVCC control so can't be statically set.

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Answer 9 · 2024-04-30T06:36:46Z

jetlag answered · Apr 30 at 06:36 AM

Did you try the proposal from @MondeoMan? This sound like it could solve the problem.

I have the same situation and will try it as soon I have enough solar power comming in the next days.

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jetlag commented · Apr 30 at 09:59 AM

Ok, this does not work. Setting a negative grid setpoint will force the MP2 to discharge the batteries in moments where the AC coupled PV can't deliver...

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Answer 10 · 2024-05-01T08:25:28Z

bernhards answered · May 01 at 08:25 AM

I have implemented it in Node Red by setting the DVCC Max Charge Current to the Amps the MPPT delivers (+50W). Together with the forecast.solar and some safety functions (JK BMS max voltage and battery temperature). In case of bad whether conditions the Multiplus2 is used, too. Works pretty good

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dutchsolarfreak commented · May 01 at 08:53 AM

Could you share your nodered flow?

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bernhards dutchsolarfreak commented · May 01 at 08:32 PM

Yes, when completely done.

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Answer 11 · 2024-05-01T21:00:29Z

palom170 answered · May 01 at 09:00 PM

Hello, I am really so sorry for my bad English. What you want to do is possible using an assistant called control limit charge or similar.

It uses the aux what you chooses and when you close the contact it doesn’t charge. It is configurable in the assistant.

Have a look to that assistant. You can start using the default values.

Try it!

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