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enfrafer avatar image
enfrafer asked

Victron ESS with a non Victron EV charger

After a Victron ESS installation at home, I am trying to find a solution to use my non-Victron EV charger normally. My new installation has a system configuration that includes a Fronius with a string of solar panels and a Victron (Multiplus + Cerbo + mppt) with a second string + batteries (2 x dyness A48100).

My EV charger (brand Policharger) has 2 AC amperimetric clamps, for dynamic charging according to home loads and PV surplus.

amperimetric-clamp.jpg

Since the Victron installation the clamps do not measure correctly when the battery is charging or discharging. However, if the batteries are idle the clamps and the EV charger work fine.

As of today, to use the EV charger, I need to manually play and activate the “keep batteries charged” mode or set the SOC target above the current value. Doing this manually every day is not very convenient, so I am looking for a better solution:

  • Should my EV charger be connected in a different way to the Victron ESS?
  • Is there any configuration to automatically detect a high load (EV charger) and then put the battery into idle mode?
  • Any other option?

I got an interesting suggestion to install and use Node-Red, however since I read Node-Red is not supported by Victron, I would like to find other ways. I am assuming the solution to my challenge would be very useful to other new Victron installations where there is a non-Victron EV charger.

Thank you!

cerbo gxESSev charging station
amperimetric-clamp.jpg (797.1 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
@enfrafer

By not supported Victron mean that they wont help with config or problems related to integrated items.

They have however made it a possibility to add it simply to their GX for those who want to third party connected things and play

It does not void the warranty and the GX can be set back to factory image if something is not working right.

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enfrafer avatar image enfrafer Alexandra ♦ commented ·

Thank you @Alexandra. I have installed Node-red on the GX and connected to my home automation system (Jeedom) quite easily. In addition, I have been able to modify the minimum SOC % with the Victron palette. So first of all, thank you for your recommendation, even if I was a bit reluctant to use Node-Red I have to say that it has been very easy and seems that opens a lot of opportunities.

Now, my challenge is to interface with the EV charger (Policharger). This charger has a RS485 connection available so my guess is the interface is possible.

My initial solution is:

1. Get the USB to RS485 cable from Victron to connect the EV charger to the GX.

2. Activate the Node-Red modbus palette and interface with the EV charger.

3. Create the logic for keeping the batteries idle (using the minimum %) when the EV charger is working.

4. Create the logic for dynamic charging the EV according to PV surplus.

Do you have any experience using Node-red on GX and interfacing with RS485 devices? Since this is my first time to connect a GX with a RS485 using the cable any suggestion would be highly appreciated.

Thanks

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Alexandra avatar image Alexandra ♦ enfrafer commented ·
@enfrafer

No experience with the rs485 interface, but it is on my list of things i would like to get into if i get the time (and toys)

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6 Answers
Richard Norman avatar image
Richard Norman answered ·

Hi, which ac out did you use? I don't have any AC out in use currently so I can't really advise on the behaviour during car charging but I suspect it will be the same as the ess management of acin and it will switch the AC only.


The zappi has a grid curtailment setting to limit charging, can be combined with an Eddi if needed to manage across multiples but if you have your own immersion heater I guess that's why you plan to use the multi acin limiter to capture them all.


50amps is a fairly generous limit if that's what you get, I charge a hybrid at 3.6kw, the Eddi at 2.7kw, house base load of 400w and the battery's through my 5000multi 3.4kw and I'm sub 47amps AC I had to also charge my dad's car and get the dishwasher on to push past and that's was a 15kw AC load.


Makes me think about taking my whole house behind ac-out 1 for ups backup as I don't really ever hit the 50amp limit. If I had the zappi on the incoming feed multi would allways be man enough.

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sharpener avatar image
sharpener answered ·

You do not say how the Policharger is connected in relation to the Victron ESS.

I would expect that the Poli grid current sensor must be situated next to the grid connection.

Then if you set the ESS|Grid Feed-in| to export surplus from both AC and DC panels, when there is a sufficient surplus the Poli will detect this and turn the charger on.

At least, that is how the Zappi is supposed to work and I am supposing here the Poli is similar.

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enfrafer avatar image enfrafer commented ·

Hello @sharpener, if I understand well, you are proposing to place the Poli sensor to measure the PV surplus (as export to the grid). I think this is a wise suggestion and might work! As explained the Poli has 2 AC amperimetric clamps, one measuring the home loads and another for the PV generation (not surplus). Since the Poli EV makes the calculation of surplus (PV - home loads), I have to check how to make home loads = zero and this should work.

Now, I need to check if for the other mode to charge the EV (from the grid - e.g. during night) the limit of the grid in the inverter with 20 A is sufficient, which corresponds to my 4,6 Kw contract. Maybe if the Poli does not see a home load it will not be able to modulate the EV charging.

I will let you know; in the meantime, thanks so much for your idea!

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sharpener avatar image sharpener enfrafer commented ·
If you connect the home loads current sensor to the terminals on the Poli and close the clamp without clamping it over any conductor then it will think the home loads are zero and you should be OK.
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enfrafer avatar image enfrafer enfrafer commented ·

Hello @sharpener, I finally realized that if I feed the Poli with the PV surplus info, when the Poli starts to charge the EV, the surplus will go down to zero and the Poli will understand there is no additional surplus and stop charging. Don't know if you have any comment or suggestion, but I think the Poli needs to get a PV input data separately, I mean that does not depend on the load.

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sharpener avatar image sharpener enfrafer commented ·

The zappi has a setting called Export Margin, to fix this problem you set this so there is always a small amount of export e.g. 100W, does the Poli have something similar?

I am installing my new zappi today, maybe I will have some further ideas after I have done that.

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enfrafer avatar image enfrafer sharpener commented ·
I don't think so. I continue to investigate. Also waiting for the USB to RS485 cable to see if I can play & connect with the Poli through Node-Red.

Thanks so much!

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Richard Norman avatar image
Richard Norman answered ·

Hi, I had a similar issue with my ess and a zappi, the only way to stop the ess attempting to meet the load you need to connect the charger on the dno side of the grid meter, so that the victron system isn't aware of the load.


I used to do as you and switch the inverter off but I also have time of day tariff where I have now setup a charge event in the ess, during this state all house load is provided by the grid so I charge my house battery and the ev just fine.


Even once the battery reaches the specified SoC it doesn't provide power for the entire period. So even if you left a 10% SoC limit during your cheap charging period you would have neutralised the ess even in summer and leave charging capacity for solar.

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sharpener avatar image
sharpener answered ·

Hi @Richard Norman you might have some further thoughts on this.

I am waiting for a response from my DNO but I think they may want to impose an import limit for my zappi. So I have wired it on the AC-Out of my Multiplus 5k in order to make use of the Multi's 50A current limit feature. This will leave 18A for charging my Pylontechs during the night and doing this will as you suggest also stop the ESS from trying to charge my EV.

The zappi has its own CT which is on the meter tails to detect excess PV being exported (not much risk of that atm!), is there anything else from your experience that I need to do?

I also have an immersion heater controller of my own making which also measures the surplus, that requires about 100W export to turn on fully. I am hoping that I will be able to choose which has priority by setting the zappi's Export Margin to be greater or less than that figure.

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sharpener answered ·

@Richard Norman wrote "Makes me think about taking my whole house behind ac-out 1 for ups backup as I don't really ever hit the 50amp limit."

I have the whole lot working from AC1-Out so as to have the UPS capability. Might have used AC2-Out for the zappi if I had planned it from the outset, but then the rainwater treatment plant in the garage would not have UPS power. Have fitted changeover switches so I can bypass the MultiPlus if it fails, final step is to automate that to be fail-safe so the freezer keeps going when we are away.

Had been waiting for a sunny day but finally completed the zappi commissioning yesterday. It needed the Export Margin increasing to 100W but after that it only uses the excess solar in Eco+ mode as intended. It remains to be seen whether it will fight with the immersion controller though.

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Tobias Franklin avatar image
Tobias Franklin answered ·

I made a low tech solution here - gets you 80% the way there and very easy!

https://salesforceconfig.com/victron-solar-ev-charging-on-a-budget/

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