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Discussion Starter · #1 ·
Where there's 3-phase power available for public charging, and where there's multiple sockets, do the installers try to balance the phase load by rotating L1/L2/L3 to L2/L3/L1 and L3/L2/L1, given that most vehicles on the road today can't actually use 3-phase charging, and so will always draw from the L1 conductor of the type 2 socket?

Do any public AC chargers actually loadshare cleverly, where they change the available output power to each outlet based on the draw from the others, so when a vehicle is tailing off the current draw because it's getting full, it can advertise more current to the other outlets? (I know the Tesla superchargers do that with DC)

e.g.
Chargepoint is fed with a maximum 32A feed.
Car 1 is a 3.3kW Leaf, chargepoint advertised 32A capability, it connects and draws 15A worth of charging.
Car 2 arrives, a 6.6kW Leaf, chargepoint notices other outlet in use at 15A, and reduces offered current to both sides to 16A.
Car 1 is nearly full, and is drawing far less, dropping down to 6A. so the chargepoint can re-advertise a higher current to car 2 (22A), but less to car 1 (6A).
Car 1 disconnects and drives off. Car 2 is then offered a full 32A charge.

OpenEVSE hydra does similar, but does it just by halving the advertised current, rather than adjusting continuously based on drawn current.
 

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Discussion Starter · #3 ·
With regards to rapid chargers, all but the most expensive DBT units don't even try to load share. Guess how many of those get sold?

I think that the Siemens rapid chargers, and ABB rapid chargers will load share between the different connectors. The only time I've been near one where it might have been possible, we both wanted the CHAdeMO connector.
 

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I can't take full credit I built upon another members work (I can't find the post)

The problem really isn't the sharing algorithm, thats a field that has been researched to death - but not in the context of EV charging.

ABB and APT produce units that can share power, the ABB rapid units can share intelligently much like the Superchargers can, Siemens/Efafec Rapids I think are dumb split down the middle as are DBT. The problem is that if you were to install 10 x 7kW units with a sharing controller (APT make such a system) you still have to size your supply to the total rated power requirements so in this case 70kW, so even if you can do all the science and share resource you gain nothing because the regs don't take this into account.

Similarly if you install 3phase EVSE, all EVSEs should be capable of supply max simultaneously.
 

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Discussion Starter · #6 ·
Similarly if you install 3phase EVSE, all EVSEs should be capable of supply max simultaneously.
Not so. There's plenty of units out there that will load share between two sockets, but in a 50% split way. APT, and I think Elektromotive can do that. APT certainly make 3 phase units that will split 22kW into 2x11kW as necessary. The system is fed from a single 22kW three-phase supply.
 

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Not what I meant should have been clearer, has to be sized to the type sticker on the device, whether that device shares that out 2 sockets is up to the device. But that only applies as far as I am aware to a single self-contained unit. So in a car park setting where you might have 10 (we can dream) units, separated across spaces you start to come unstuck, as I think most if not all systems are modular and rated individually and not as a whole system.
 

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@Simon Hewison : If you've got more then one EVSE then they generally can't talk to each other and you need to add up all their max capacities to find the capacity for the main fuse. So if you've got 4 EVSE's that are rated at 22kW (3 phase 32A) you need 3 phase 128A available at all times, even though a few of these EVSE's might only draw from a single phase at a time. Then again, the cost of the thicker cables and main fuse are negligible compared to the cost of the EVSE's and the electricity drawn over the years.
 

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The problem is that if you were to install 10 x 7kW units with a sharing controller (APT make such a system) you still have to size your supply to the total rated power requirements so in this case 70kW, so even if you can do all the science and share resource you gain nothing because the regs don't take this into account.
I don't think this is a regs problem - the regs say:

Where the final circuit supplies more than one charging point no diversity shall be allowed.
Diversity may be allowed for a dedicated distribution circuit supplying multiple electric vehicle charging points if
load control is available.
What's being discussed here should fall under the 2nd sentence.
 
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