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smejfi avatar image
smejfi asked

Victron EV charger without ESS and inverters

Hi all, I have a question regarding the Victron EV charging station. As far as I know, the charging station in combination with ESS should be able to limit the charging power according to the main circuit braker, so ev charging wont overload the breaker when other house loads are running. I have not tested this so far, although I have allready installed a few of those chargers, but I believe this actually works. My question is, if it is possible to install stand alone Victron EV charging station (without inverters and therefore without ESS) and still benefit this feature? Of course I understand that there would have to be an external energy meter which would measure how much power goes through the main circuit breaker and probably there would have to be GX device as well, but if there are these components (Charging station, GX device and energy meter), will this charging power limiting feature work? Also now when new Victron energy meter came out, I was wondering if this was possible also without gx device, but that is probably too much to ask. Thank you for your answers.

ev charging station
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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Yes, it works without ESS, on both grid connected or off grid installations
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smejfi avatar image smejfi Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Thank you for your answer, I get that for Carlo Gavazzi energy meters the gx device was necessary to comunicate with the meter, is this also the case with Victron brand energy meter?
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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Are you sure no further disclaimers are needed here ? As discussed in other threads, overload protection in my setup will not work simply because it is designed to do something different. That's OK, but I did actually buy the chargers because you said "no problem, use overload protection". I ended up writing the node-red flows to accomplish load-balancing myself.

Again, so many people, so many setups. Node-red and modbus are life savers.

In an ESS setup, overload protection max amps is read only. It is taken from the max amps input of the Multi's. No matter if this value actually represents your grid connection max amps. But even if that is no issue for this forum-member / use-case.... than still, during overload detection, the power will only be reduced and if below 6A it will stop charging. And it will never restart. That is proper overload protection but it is most certainly not load balancing.

Writing a flow is not super difficult but the fact that charge current cannot be 0 results in added complexity as you need to cook something up to stop and restart without influencing manual or scheduled stop and start.

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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ kudos50 commented ·

Electric vehicles are not charging below 6A, so I'm not sure what you can do about that.

Then, yes, for most of the systems, maximum AC current, is the one defined inside multi. For exceptions, there is Modbus control and NodeRed is just the perfect tool.

It's pretty hard to have a solution to fit all the possibilities.

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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
If charge current lower than 6A, than charge current is 0A should result in the vehicle reporting SuspendedEVSE instead of SuspendedEV.

From a charging perspective there's not much difference. From a programming perspective it will prevent you from having to write logic for a restart. Without it, you simply do not know if the logic stopped charging or something else. As a result it will start just because grid headroom is =>6A.

In all honesty I think my other remark is more important and less dependant on setup: If overload protection stops the charging process it will never restart. So don't mix and merge the term overload protection with load balancing.

For me, node-red makes it all OK. Happy user. For this particular thread I read between the lines that we're talking about an installer. Using node-red flows to accomplish load balancing as I do might not be his/her cup of tea. Customers like a supported solution.

Happy to share though. It's not that complex. Specially not for a single charger.

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smejfi avatar image smejfi kudos50 commented ·

Thank you very much for your contribution. Yes, Im an installer and although Im used to use Node Red in some cases, this is the case where I would expect originally supported solution. So let me ask again, I was assuming that overload protection means, that in case there is an overload caused by the combination of ev charging and other house loads on one or more phases, the ev charging current will be automatically lowered to prevent the overload. I also assumed that in case this would mean lowering the charging current below 6A per phase, it would stop temporarily charging ev until there would be sufficient current available again and then it would start charging again. According to your description this doesnt seem to be the case, does it? So by the term "load balancing" you probably mean what I just described above?

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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ smejfi commented ·
If the available power is below 6A, it will stop, restart after a while, stop again etc. If the EVCS is not able to continue charging it will stay stopped to prevent overloading the system.
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smejfi avatar image smejfi Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Ok, but how many times does it have to stop and restart after a while until it gives up and stays stopped? And once again, will this feature work "out of the box" also without inverters present in the system as I originally asked? As @kudos50 sugested, the limit power is taken from the inverter setup, so what if there is no inverter?
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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ smejfi commented ·

If there is no inverter, you can define the current, it is explained into the manual

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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·

I think what you are explaining here is precisely what I observed before concluding I needed node-red. It really is overload protection and therefore protects the system (in my case multi's) from overloading. If a heavy peak load like a dishwasher or washing machine is heating water several times before starting the next wash phase, the EVCS will eventually not restart the charge process. This is a great feature, but it's not loadbalancing as (the term is) mostly used by other vendors.


@smejfi please realise my setup is not very common. I have 3x25A grid at the house with a 3x16A 50!meter connection to my multi's in the garage (and back for small no-break loads). Therefore the 16A configured on the input of the multi's will not work with overload protection using that same number.

I have 2 x EVCS NS. One on AC-in and another on AC-OUT. I wrote a node-red flow that loadbalances a max 20A current between the 2 with a 5 minute wait in case total remaining continues to be less than 6A.

I do agree with Lucian that it's almost the same. But as always the devil is in the details. It will not raise the charge current again after lowering it and It will not keep restarting to protect the multi's and/or other components. Whereas a consumer just wants the car to be charged in the morning no matter the amount of attempts or the time between attempts.

<edit> Let me add a disclaimer myself. Behaviour is from what I observed. Specifically not raising the current after lowering it and a cap on the amount of restarts. In the end it's just firmware and choices I guess.

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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ kudos50 commented ·

Below 6A is charging stopped.

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