question

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cyril-ev asked

EV Charging Station - maximum COMBINED amps

Hello,

I already have a grid-connected installation with:

- Multiplus 48V-5kVA

- 2x MPPT a total peak 8kW solar

- 4x Pylontech US2000C

- Cerbo GX

Everything works well, I'm really satisfied with this.


I also have an EV (Tesla), and a Tesla wall charger. I made a home-made script which gets the Victron info from Modbus, the Tesla info from the Tesla API, and starts/stops/sets the charging amps automatically. In fact, it does almost the same thing as the Victron EV Charging Station.


Now, I'm going to get a second EV, a non-Tesla one, without any API to control it. So instead of having one Tesla charger, I plan to have 2 Victron EV Changing Stations (the NS model). I have read the manual and some posts on this support forum, and I still have one question:


Is it possible to set a maximum combined amps for the two chargers? I know I can set max amps for each charger. But I want to be able to charge only one car at 20 amps, or both at the same time at 10 amps each. The total must never exceed 20 amps. When charging with solar of course it won't go over 20 amps (because the 5kVA Multiplus is the bottleneck), but when setting the charge to manual, It could go to 40 amps, and I really can't afford this.


Also, if some Victron employee reads this, I'd love to emphasize what other people have already asked:

- having the possibility to get the AC IN from the bottom or the back of the charger is good. Adding a possibility on the top would be even better. Or maybe I could drill a hole on the top, and add a nylon gland myself?

- having the possibility to have a non-removable cable instead of a type 2 plug would be awesome. I understand that you made this choice because not all cars have a type 2 plug, so anyone can use the appropriate cable. But if you don't provide the cable, one could also connect his preferred cable directly inside the charger, just like we do for the AC IN. In fact, it's probably doable right now, isn't it? If I disconnect the short wires inside the charger, I should be able to replace them with the wires from a cable of my choice. I'll pass the cable in the free bottom nylon gland (maybe I'll need a bigger one and enlarge the bottom hole, that shouldn't be a problem).

Thanks a lot for your help!

ev charging stationev charger ns
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cyril-ev answered ·

@Lucian Popescu (Victron Energy Staff) any insight on this?

Thank you.

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

"Is it possible to set a maximum combined amps for the two chargers? " - yes, that's the overload current. When exceeded, devices will reduce power or stop if already charging with 6A

"Adding a possibility on the top would be even better" - the is not pre-drilled hole on top. And I wouldn't recommend passing the cables from top for multiple reasons (water can go inside easier, high current AC lines will pass near some areas that are can be affected by EM etc)
"it's probably doable right now, isn't it? "- Yes, you can probably do that yourself, I heard that some other users did that. Or you can buy an extra type 2 cable and leave it connected, it's simpler.


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kudos50 avatar image kudos50 Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
side note from another thread; you cannot actually set the overload value. It's inherited from the Multi AC-IN input current limit. Even if you move it between AC-IN and AC-OUT locations.


In all honesty, I tested with a single device last weekend and have the same situation you have with 2 EVs. Single device on a 16A overload setting works fine but it does require some reading. IF the limit is hit too often (or too long cannot remember) it will stop charging. If configured for manual start it will not restart. Not sure why that is but I can imagine using 2 means you hit the limit more often.

Still considering to buy a second NS to replace the EVBox Elvi. With the Victron ESS "ecosystem" it's just easier to hook it all up without custom programming.

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Lucian Popescu (Victron Energy Staff) avatar image Lucian Popescu (Victron Energy Staff) ♦♦ kudos50 commented ·
Glad to hear this! And we are open to improvements.
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kudos50 avatar image kudos50 kudos50 commented ·

Sure I do... question is if they are just unique to my use-cases and setup :-)

I do have one on this topic. The current feature is really designed around overload protection of the Inverters instead of the grid as long as that's the same thing. In my case it's not (25A versus only 16A). Because it uses the grid meter setup from the multi's it happens to provide a limited form of load balancing. If I replace my Elvi with another Victron unit I will end up having one unit on AC-in and the other on AC-out (physically no alternatives).

Would be good to learn a bit more about the plans for the EV charger overload protection to work together with the new ESS/DESS grid parallel overload feature that Dirk-Jan says you guys are working on. Also, prioritising between 2 EV chargers that are in conflict during power limiting could be something to think about. The added complexity of having 2 EV chargers and DESS deciding to charge batteries from grid simply won't fly on 3x25A :-)

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cyril-ev avatar image cyril-ev Lucian Popescu (Victron Energy Staff) ♦♦ commented ·
Thank you for your answers!
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