Home charging outlets - load sharing

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Chuq
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Home charging outlets - load sharing

Post by Chuq » Sun, 18 Mar 2018, 15:08

(This is one of a number of topics related to home charging. Since the questions are separate, I'll post each in a separate thread! Other threads - Simple type 2 outlet for home charging, Solar diversion)

I currently have some of the plaster sheeting removed in my garage, so I'm looking at putting some EV charge outlets in for future proofing. I plan to have two outlets in my double garage, and a third outside in the driveway (for guests, or other situations where I may not be able to access or use one of the internal garage outlets)

Of course I am conscious of the total electrical capacity of my home and am wondering if I can set these outlets to load share across a single circuit, to limit my peak demand.

I'm being conservative and am planning to have three outlets share a 32A single phase connection. So a single car plugged into one outlet will draw 7kW, if two are plugged in each will draw 3.5kW, etc.

The only systems I've seen where this is possible is Tesla HPWCs, which allow four on one circuit, and some Clipper Creek units sold in the USA. In both these cases the "smarts" seem to be in the wall units themselves. Is it possible to configure load balancing in an EVSE-agnostic manner? I'd prefer to run the wiring now and select the EVSEs later when I need them (at the moment our only EV is a Leaf, which charges using a 10A EVSE plugged into a 15A socket, so no need to get spend $1000s on wall units just yet!)

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reecho
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Re: Home charging outlets - load sharing

Post by reecho » Mon, 19 Mar 2018, 17:59

Look up OpenEVSE "hydra"

Don't know if it's still in development....

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Re: Home charging outlets - load sharing

Post by antiscab » Tue, 20 Mar 2018, 00:18

Just put in 3 x 15A power points and remember to only use two at a time.

How many cars do you have to charge?
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Re: Home charging outlets - load sharing

Post by Chuq » Tue, 20 Mar 2018, 20:16

reecho wrote:
Mon, 19 Mar 2018, 17:59
Look up OpenEVSE "hydra"

Don't know if it's still in development....
Found a video! It looks good for a homemade creation, but doesn't seem to do what I wanted (it doesn't intelligently balance the supply - e.g. when he connects the second load the first drops from 30A to 15A even though the second is less than 1A). Understand it's a home-made job, so still rather creative. The kind of thing Greg would have in his boot :)

https://www.youtube.com/watch?v=bX33EAvZMNs
antiscab wrote:
Tue, 20 Mar 2018, 00:18
Just put in 3 x 15A power points and remember to only use two at a time.
Right now - I have one Leaf. So I have one 15A, and that's fine. My thing is that at the moment I have the plaster ripped off the ceiling of my garage and am considering taking the opportunity to install the wiring to future proof my place. I consider 3x outlets, any one of which can handle 7kW on its own, as the bare minimum for when EV are ubiquitous. But I'm also conscious of (a) having no idea what additional capacity my house can handle, so I'm conservatively assuming I'll only having capacity for another 7kW of load, and (b) the effect on the grid of suddenly having 2x or 3x devices drawing 7kW for hours at a time.

My off-peak tariff runs from 9pm to 7am, so can pull 70kWh from the grid over that period. In the hypothetical future I'd like to have my families Leaf and Model 3 (which have done 20-30 km each commuting), and a friend's Kona (who has driven 200 km from Launceston to stay overnight) and have the ability to plug them all in at 9pm, have them all full by the morning, and know that I haven't drawn more than 7kW between them at any one point in time.

Real life, at this point in time - my Leaf charges off the 15A, my other car is a gas guzzler, and if someone from Launceston travels down in their Outlander PHEV I can unplug the electric gate from it's 10A socket, and they can plug an EVSE into that, assuming it's not raining... it's fine, it's half the fun of being an early adopter. But it's also fun being able to see the future just before it happens .. and be ready for it :)

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Re: Home charging outlets - load sharing

Post by 4Springs » Wed, 21 Mar 2018, 17:24

Chuq wrote:
Tue, 20 Mar 2018, 20:16

My off-peak tariff runs from 9pm to 7am, so can pull 70kWh from the grid over that period. In the hypothetical future I'd like to have my families Leaf and Model 3 (which have done 20-30 km each commuting), and a friend's Kona (who has driven 200 km from Launceston to stay overnight) and have the ability to plug them all in at 9pm, have them all full by the morning, and know that I haven't drawn more than 7kW between them at any one point in time.
It's nice to know you are preparing, but how did you know I was after a Kona??

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Re: Home charging outlets - load sharing

Post by Chuq » Thu, 22 Mar 2018, 19:03

4Springs wrote:
Wed, 21 Mar 2018, 17:24
Chuq wrote:
Tue, 20 Mar 2018, 20:16

My off-peak tariff runs from 9pm to 7am, so can pull 70kWh from the grid over that period. In the hypothetical future I'd like to have my families Leaf and Model 3 (which have done 20-30 km each commuting), and a friend's Kona (who has driven 200 km from Launceston to stay overnight) and have the ability to plug them all in at 9pm, have them all full by the morning, and know that I haven't drawn more than 7kW between them at any one point in time.
It's nice to know you are preparing, but how did you know I was after a Kona??
Well I guess 220 km will also be fine :P

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