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Discussion Starter · #1 ·
New house has three phase (plus single phase, somehow - two meters). Plenty of room for installation, spare ways etc.

Given I have:
  • my Chargemaster ‘disc’ charger from the old house
  • a new EV qualifying for the installation grant

what would you do to get things set up so I can charge two EVs at once?

I’m not considering three phase charging just yet, we do have a Zoe (and Leaf) but 7kW is fine for us right now in terms of mileage
 

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I would:
1. Question why you have 2 meters, make sure you are not paying an extra standing day charge.
2. Go for three phase charging, the price difference for the Zappi 22kW is not that much different from the 7kw, dependent on your cable run. It will future proof your install and balance out your loads.
3. Get an electrician to install the chargemaster, but use a 5 core cable utilising only 3 cores and earth the other 2. When you need to upgrade, replace the chargemaster for another 22kw zappi.
 

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Take care balancing the loads across the phases - most EVs charge on just a single phase (L1) and it would be very easy to end up drawing 64A from a single phase which may be close to the limit. I have seen some charge point deliberately wired L2 to L1 to avoid this issue.
 

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Take care balancing the loads across the phases - most EVs charge on just a single phase (L1) and it would be very easy to end up drawing 64A from a single phase which may be close to the limit. I have seen some charge point deliberately wired L2 to L1 to avoid this issue.
Excatly why you should go with a unit that has load balancing intergrated into the unit like the Zappi.

Bit off track, but do you think its possible to install a TP Zappi and wire to SP?
 

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The obvious thing to do is use different phases to supply the two charge points. All supplies along roads, etc are three phase usually, all the DNO does normally is split houses off so as you go down a road every adjacent house is on an alternate phase. With a three phase supply then you can either opt for three phase charge points or just fit two single phase charge points, with each on a separate phase. Unless you have a real need to charge at 22 kW, and one of the very few cars that can actually use three phase, then there doesn't seem to be much merit in fitting three phase charge points. You really need to be driving a very high mileage every day to justify three phase charging at home.
 

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Discussion Starter · #6 ·
Thanks all. Currently the loads are split (3x100A fuse holders)

L1 - 6A
L2 - 26A
L3 - 40A

I wonder whether the L1 is also where the house supply is connected (before the billing meter, it is a separate metered supply)

I suppose I could install 2x 11kW chargers (total 32A per phase?)

also any complications with an approx. 15m cable run?
 

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I suppose I could install 2x 11kW chargers (total 32A per phase?)
A 11kW is 3.6kW per phase, fine for the Zoe (and a lot of other cars) but if you have a 6.6kW LEAF it'll not be charging at it's potential as its only single phase. Whether that's an issue depends on how fast you need to charge.
 

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I'm a bit confused. What's using the L2 and L3 if your house is on L1? Also are those typical, a snapshot, or maximum currents?
 

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Discussion Starter · #11 ·
A 11kW is 3.6kW per phase, fine for the Zoe (and a lot of other cars) but if you have a 6.6kW LEAF it'll not be charging at it's potential as its only single phase. Whether that's an issue depends on how fast you need to charge.
Ah I didn’t realise that the Leaf will not draw 7kW from a 11kW three phase, but of course it makes sense that it wouldn’t. May need to do one single phase then.
I'm a bit confused. What's using the L2 and L3 if your house is on L1? Also are those typical, a snapshot, or maximum currents?
The house is on a completely different single phase supply with its own meter. On the three phase supply, those are the maximum ratings of the MCBs. I suspect L1 might also have a pump connected to it related to a sewage tank but I don’t own the property yet so my opportunities to poke about are currently limited :)
 

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Discussion Starter · #12 ·
We've finally moved!

I have a spare circuit (L1/L2/L3) on the three phase distribution board. Can I use it to power two 7kW chargers? I'd like to run a single cable across the driveway - or install ducting/dig a trench for it at least. Can I use one cable for this?
 

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Run a suitably protected three phase, 5 core, sub main across the drive, terminate it in a suitable small enclosure and then split off two single phase cables off to each charge point. Might be possible to fit an extra gland in one charge point and run the three phase cable to that, then loop out to the other one. You might save money by fitting a three phase connection box at the feed to the sub-main, with open PEN and DC tolerant earth leakage protection, as that way the charge points can be simple units with no additional protection.
 

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The Easee Robot chargers talk to each other over WiFi/mobile to load balance and are also three phase capable. So, if you plugged in one car you'd potentially get the lot (up to what the car could take) & if you plug two in they will share nicely. You can even use their app to tell the chargers which proportions to use, I think e.g. if you wanted one to be higher priority than the other. Not terribly expensive either.

I don't have one, but I am considering...

Kind regards
- Garry
 
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