[Peak Steve]

For various reasons, my customer has two 3-phase chargers (22kW) but only 2 x 100A phases available (un-used).
The chargers (Myenergi Zappi 22kW) are perfectly happy for the 3 internal separate "phase" chargers to each be supplied by a single phase, but the big question is: Are EVs?

To reiterate, each supply is capable of supplying a full 100 Amps. But will various vehicles accept 3-phase inputs that are in-phase with each other?


Alternatively, would vehicles be happy with only 2 x 7kW phases (i.e 14kW) of a 3-phase charge?

Any help would be gratefully received.

 

[dk6780]

Alternatively, would vehicles be happy with only 2 x 7kW phases (i.e 14kW) of a 3-phase charge?

Most will be ok, but early Renault Zoë may be damaged if the connection is to L3 rather than L2.
I don't know the answer to the question about the two connections using the same phase - sorry - but will be interested to know.

 

[Peak Steve]

TO CLARIFY: My customer's 2 chargers (above) are NOT YET INSTALLED.

 

[Peak Steve]

Most will be ok, but early Renault Zoë may be damaged if the connection is to L3 rather than L2.
I don't know the answer to the question about the two connections using the same phase - sorry - but will be interested to know.

Thanks. So, do you mean L1 & L2 would be OK as a 2-phase supply?

 

[dk6780]

Yes. But not L1 and L3 unless you ban early Zoë. Also note that a lot of cars will charge no faster with two phases than one as they switch the charger from an unused phase to charge faster from the single phase, e.g. an 11kW three phase charger in the car is 3x3.6kW units, but when charging single phase it uses two to get 7.2, the same as it would get on two phases.

 

[mikegs]

A couple of potential issues.
It will depend on how the car configures for multi-phase operation. If it uses a delta then the same phase on each leg obviously won't work.
For a star connection the neutral only carries the unbalance current. If you connect the same phase to two arms the neutral will have to carry the combined current of both. Shouldn't be a problem for 3.6kW paired, but if they are 7.2kW that's 60A or so.

 

[JeffG]

I don't really understand the question in the title. By definition, the three phases of a 3-phase supply are 120 degrees apart.

 

[mikegs]

I don't really understand the question in the title. By definition, the three phases of a 3-phase supply are 120 degrees apart.

Had me a bit confused but he seems to be asking about using just 2 phases and/or connecting a single phase to two of the 3 phase inputs of the car to double the power ... I think.

 

[dk6780]

That's my interpretation of it, the same phase repeated in each of the phase wires. But as you say, the neutral will be the issue.
So the answer to the OPs question is to use just the two available phases separately as single phase chargers.

 

[Kingpleb1]

As above I can't see it working.

The customer would be better served probably with 3*7kw chargers on each phase. It would technically be just below the limit but would give them the ability to charger more vehicles at a higher speed.

Unless it's really just for 2-3 vehicles that are capable of 3 phase chargjng.

Is there a reason the 3rd phase isn't available to use at all?

 

[cDy]

Yes. But not L1 and L3 unless you ban early Zoë. Also note that a lot of cars will charge no faster with two phases than one as they switch the charger from an unused phase to charge faster from the single phase, e.g. an 11kW three phase charger in the car is 3x3.6kW units, but when charging single phase it uses two to get 7.2, the same as it would get on two phases.

Spot on. My understanding was that (except for the ZOE) most, if not all, cars supporting 3 phase charging used this approach, so there would be no charging speed benefit from connecting two phases instead of one. A pointless exercise.

With regard to the ZOE, here's a discussion of the likely form of the charging circuit: Charger design article on CanZE site

I think the neutral is switched out for three phase charging. (One of the relays can get welded closed if you connect to an incorrectly wired 3 phase charger.)

All the current flow is between the phases. I've not worked it out, but if you remove a phase you may well lose more than 1/3 of the current flow?

And finally, it's clear that for the ZOE the phases do have to be 120 degrees apart.

 

[andrew*debbie]

Mercedes B250e and BMW i3 with 11kW on board will work with the same phase on L1 and L2. The i3 has 3 3.6kW on board chargers. It even ties two in parallel for 7kW single phase operation.

Zoe needs true 3-phase power or single phase on L1 only.

It is a bit risky since you don't know what people will plug in to the chargers 2 or 5 years from now.


Odd that a customer has 2-phase power. I've never seen that.

 

[andrew*debbie]

understanding was that (except for the ZOE) most, if not all, cars supporting 3 phase charging used this approach,

B250e is the execption. It doesn't have internal relays. The only way to get it to charge at higher than 3.6kW is connect power to L1, L2 and optionally L3.

 

[dk6780]

Odd that a customer has 2-phase power. I've never seen that

I interpreted the OP to mean that they have 3 phase but have used most/all of the capacity on one phase meaning that there are only the two other phases with capacity left. I have come across similar situations many times in the past.

 

[Peak Steve]

Thank you for all the replies. Apologies for not making myself clear:
The (domestic) customer has 2 EVs and wanted 2 x 22kW chargers, but only had 2 "spare" phases (the third was already fully utilised as a single phase supply).
The original costs of installing a new supply had skyrocketed (not helped by the seemingly random manner in which SSE "calculate" installation quotes), so he had purchased (or more importantly - I had purchased for him) 2 x 22kW 3-phase chargers but with only 2 phases available!

My thought process was:
1. Could L1, L2 and L3 of a charger be commonly connected to a single phase source of power? A single phase 100A supply would be just enough to provide the 22kW required, and the charger manufacturer confirmed the charger "doesn't care". So it was a query regarding how 3-pase vehicles utilise the power to charge their batteries (if there is a common standard), and if they would accept the same single phase on each of their 3 inputs. Obviously if they are Star/Delta arrangements there is an issue, but as dk6780 pointed-out above, some 16A chargers combine L1 and L2 inputs in certain circumstances.

Or
2. My other option would have been to utilise the 2 phases available and connect (e.g) L1 and L2, but leave L3 disconnected.

Your replies have put in-mind that the actual charging cable ( and connector) has only a single neutral core, which would have to carry some 96A, thus making my first proposition impossible
(as the conductor certainly doesn't look big enough!)


Thankfully, as of last night, the client has agreed to pay for the additional supply - so this has now become merely theoretical.

 

[mikegs]

The chargers (Myenergi Zappi 22kW) are perfectly happy for the 3 internal separate "phase" chargers to each be supplied by a single phase, but the big question is: Are EVs?

Myenergi are a bit off-piste with their info. These things aren't actually chargers, the are 'charge point's which are basically smart sockets. The charger(s) are in the car. (This is for AC, DC is another matter).
The power part of a charge point is just a contactor, which is why it doesn't care much about phases.

Thankfully, as of last night, the client has agreed to pay for the additional supply - so this has now become merely theoretical.

Good

 

[andrew*debbie]

The (domestic) customer has 2 EVs and wanted 2 x 22kW chargers

For AC charging:

Most modern "Type-2" EVs either have a single phase 30A 7kW AC charger or three single phase 16A chargers for a total of 11kW. A handful of EVs (mostly a few Teslas) have 3 32A chargers. The big execption is the Renault Zoe which has a true 3-phase charger on-board. Zoe uses the motor field coil as part of the charge circuit. Zoes come with either 22kW or 44kW on-board charger. The 44kW needs 63A per phase which is normally only found at public rapid chargers.

A 22kW charge point is, of course, 3 x 32A.

When connected to a 22kW 3-phase charge point:

A 7kW car will take 32A from a single phase. LEAF is best known example.
An 11kW car (most German EVs) will take 16A per phase.
A 22kW car will take 32A per phase.

 

[Peak Steve]

Myenergi are a bit off-piste with their info. These things aren't actually chargers, the are 'charge point's which are basically smart sockets. The charger(s) are in the car. (This is for AC, DC is another matter).
The power part of a charge point is just a contactor, which is why it doesn't care much about phases.

Once again, my own inexact use of English: Myenergi told me their Zappi product (charge point) "doesn't care" what the 3 inputs were fed with, phase-wise.
(Customers more readily understand "charger" than "point". "If it's not a charger why do I need it?" would be an expected response)

 

[Hilltop Dave]

Odd that a customer has 2-phase power. I've never seen that.

In some rural locations a split single-phase supply (230-0-230v) is provided which would result in two supply fuses in the customer's premises. The obvious clue is that the local pole-mounted transformer has only two high voltage terminals.

2-phase supplies (with the 2 phases 90 degrees apart) were provided in some areas the 1930's for driving induction motors etc, but as these required a 4-core cable (as there were two 'neutrals'), the supplies were converted to 3-phase as this made better use of the cable, with Scott wound transformers Scott-T transformer - Wikipedia being installed to power the older 2-phase equipment.

 

[Peak Steve]

Once again, my own inexact use of English: Myenergi told me their Zappi product (charge point) "doesn't care" what the 3 inputs were fed with, phase-wise.
(Customers more readily understand "charger" than "point". "If it's not a charger why do I need it?" would be an expected response)[/QUOTE]