J1772 Hydra - charge two vehicles with one charger

[nsayer]

Nick, you are a Leaf owner, so you haven't used 75A/80A charging, it moves right along.

Actually, I am a Fit EV owner, and my wife has a Volt.

Proportionally speaking, I do charge at around that speed, thank you very much. I'm just not blessed with an 85 kW-hr battery. Getting 140 MPGe does, however, make up for it.

If he expects to use a J-1772 with a J-1772 to Roadster adapter on one output, and a Tesla 80A Model S connector on the other output, to be worth spending the money on the contactors , sequential mode would be nice, plug in both vehicles and they charge in sequence. To do that, the AC wiring needs to be rated for 80A, requiring a 100A breaker and hard wired with #3 THHN copper.

Fine with me. The Hydra logic board is just fine with that if you can find the wire. It's really easy to find the wherewithal to do 60A per car - that's all I'm saying. And that's 75% of 80A for, oh, conservatively, half the money.

But who am I to judge?

Might have to use 1 GFI coil per AC conductor and a circuit to subtract them from each other (should balance to zero). The wiring will be the challenge on the dual high power hydra, but there are junctions and connectors made for this.

I would modify my 75A OpenEVSE with 2 contactors / cables but I only have 1 EV, the dual charger Model S. I'd do it to prove it could be done, if some one could actually use it when completed.

I am not an expert with current transformers. Naively, I'd say you could connect two in series and run a conductor through each, but you'd need to know for sure that both CTs were wound the same direction, I believe.

In any event, it isn't something I've tried.

 

[hcsharp]

I don't need sharing or sequencing; both garages are 20 seconds walk from my respective bedrooms. What I desire is to charge both Teslas as quickly as I can when I want to.

Do any of you have suggestions on how to do this better, ...

Leave Boulder the way it is. Stop using adapters at home because (you said it yourself up-thread) they are inconvenient except when traveling. In Pagosa Springs, do a parallel conversion to your HPWC like Lloyd's TS-70 to J conversion, except add a native Roadster connector/cable instead of J1772. The HPWC is too tight inside for space so you might have to do the parallel split in a small electrical box on the output cable of the HPWC.

@mitch672 Most breakers don't hold up very well as switches. I realize they wouldn't generally be switched live, but it's still not a very robust solution.

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Another solution for you in Pagosa is this:
http://www.teslamotorsclub.com/showthread.php/14817-Model-S-to-Roadster-adapter

I'm kind of embarrassed that it's not for sale yet but I've sent the order to my machine shop for the parts and just waiting for them to catch up on a backlog.

 

[Cottonwood]

Another solution for you in Pagosa is this:
http://www.teslamotorsclub.com/showthread.php/14817-Model-S-to-Roadster-adapter

I'm kind of embarrassed that it's not for sale yet but I've sent the order to my machine shop for the parts and just waiting for them to catch up on a backlog.

That is exactly what I want! It is the solution that I wanted for Pagosa from the start! Tesla told me that they would never make this. When I told them that I wanted this, it took me 10 minutes to get them to understand why, and then nothing happened.

I should be reading the Roadster forum more. In case I do not, please keep me on your list of people who want the HPWC to Roadster adapter! Thanks for working on it.

 

[hcsharp]

That is exactly what I want! It is the solution that I wanted for Pagosa from the start! Tesla told me that they would never make this. When I told them that I wanted this, it took me 10 minutes to get them to understand why, and then nothing happened.

I should be reading the Roadster forum more. In case I do not, please keep me on your list of people who want the HPWC to Roadster adapter! Thanks for working on it.

You're on my list. And yeah, you should be reading the Roadster forums more. And driving yours more, too!:smile: The Model S doesn't always fit on our winding back roads hear in VT, but if I lived in the wide open spaces of CO I'd probably drive the Model S more often.

 

[JonathanD]

Resurrecting this, didn't see a specific answer but maybe I missed it. We live in a townhome and only have capability for one NEMA 14-50 plug. Currently it works great for our Model S, but if we were going to get a second Tesla it would be nice to not have to swap parking spots every other day. It would be great if there was a way to split the output from the NEMA 14-15 to two different chargers, set them to charge at different off-peak times, and not have to worry about it (other than running the cables in the garage, which could get interesting).

 

[Oba]

Resurrecting this, didn't see a specific answer but maybe I missed it. We live in a townhome and only have capability for one NEMA 14-50 plug. Currently it works great for our Model S, but if we were going to get a second Tesla it would be nice to not have to swap parking spots every other day. It would be great if there was a way to split the output from the NEMA 14-15 to two different chargers, set them to charge at different off-peak times, and not have to worry about it (other than running the cables in the garage, which could get interesting).

Split the NEMA 14-50 outlet with two 25 amp breakers, and charge each car at the same time at 20 amps each.

 

[andrewket]

Split the NEMA 14-50 outlet with two 25 amp breakers, and charge each car at the same time at 20 amps each.

Simpler, but it doesn't optimize charge time. For example, say car A drives 10 miles and car B drives 200. With the simpler config of two EVSEs at 25A, car A will finish under an hour, but car B will take several hours (longer than overnight). Car B could charge faster if it could increase it's charge rate since car A isn't using the available power. An advanced EVSE could optimize this, and could be programmed to optimize on other dimensions as well depending on the user's preferences. For example, charge car A as fast as you can before charging B.

 

[Rocky_H]

Resurrecting this, didn't see a specific answer but maybe I missed it. We live in a townhome and only have capability for one NEMA 14-50 plug. Currently it works great for our Model S, but if we were going to get a second Tesla it would be nice to not have to swap parking spots every other day. It would be great if there was a way to split the output from the NEMA 14-15 to two different chargers, set them to charge at different off-peak times, and not have to worry about it (other than running the cables in the garage, which could get interesting).

A friend of mine with two Teslas does have a solution for that with one 50A circuit. They do have it branch to two different 14-50 outlets that are not used at the same time. The way they set that up is that one of the cars is set for no scheduled charging time, so it starts as soon as it’s plugged in. The other one is scheduled for something like 2 or 3AM. The first one is done charging by that time.

 

[ggr]

A friend of mine with two Teslas does have a solution for that with one 50A circuit. They do have it branch to two different 14-50 outlets that are not used at the same time. The way they set that up is that one of the cars is set for no scheduled charging time, so it starts as soon as it’s plugged in. The other one is scheduled for something like 2 or 3AM. The first one is done charging by that time.

Daring. What if you come home late from a long trip, tired and not thinking well, and plug in Car #1, and it's still charging when Car #2 turns on in the wee hours? You'll at least pop the circuit breaker; that's the good outcome. If I was going to do this I'd just install a switch so that only one could be active at a time, just in case. Or add another circuit (which is what we actually do have)... it doesn't add much to the installation cost of the second 14-50.

 

[Rocky_H]

Daring. What if you come home late from a long trip, tired and not thinking well, and plug in Car #1, and it's still charging when Car #2 turns on in the wee hours? You'll at least pop the circuit breaker; that's the good outcome. If I was going to do this I'd just install a switch so that only one could be active at a time, just in case. Or add another circuit (which is what we actually do have)... it doesn't add much to the installation cost of the second 14-50.

I asked him about adding the second 14-50. The main service for the house didn’t have room to add that extra capacity.