J1772 Hydra - charge two vehicles with one charger

[Cottonwood]

I don't have any direct experience with the HPWC. Obviously modifying it will void its warranty. I think that at the end of the day it may be a lot easier to simply construct the EVSE variant of the Hydra with two J1772 cables. With 6 AWG input wire with 90 degree insulation, and with 75A contactors, you'll be able to do one car at 75A or two at 37.5A. In principle, it would be almost exactly the same thing I did with my Mega Hydra, but taken one "notch" higher.

I went with 50A simply because I wanted to not have to hard-wire it (as an experimenter I am always plugging and unplugging), and because I presently only have a 30A car anyway (and only a 40A circuit in any event). Also, the 50A contactor I sourced was particularly inexpensive.

The only tricky part is that you have to kind of squish 6 AWG wire to get it to fit through the GFI coil. But it can be done (it was done by an OpenEVSE builder once upon a time).

The "splitter" variant board requires a J1772 pilot and proximity line on the inlet, and requires J1772 pilot signaling on the output. If the HPWC can be coerced into working that way, then in principle you could "insert" the Hydra inline and break out an additional J1772 plug. But for the cost of an additional J1772 cable, you get to keep your unmodified HPWC as a backup. I think that'd be valuable.

Thanks for the answers. Here are a few of my thoughts.

As far as I know, both the Tesla Roadster and the Tesla Model S are electrically J1772, but have their own physical connectors. That is why the Roadster and Model S J1772 adapters are just "plug adapters" changing only the physical shape of the connector. Here is info on changing the output of a UMC to a J1772: Tesla Model S UMC cut open and modified to J1772, and here is where you can order a conversion: JESLA is THE 40 amp J1772 portable charging solution!
Clipper Creek sells a 75 Amp J1772 cable to convert a Roadster UMC to a 70 Amp J1772 EVSE. Although I don't know of any examples that have put a J1772 plug on an HPWC, it should be possible.

My reason for this is to get 70 Amp charging for my Roadster from my HPWC. Tesla makes a Roadster Connector to Model S adapter, but they do not make a Model S to Roadster adapter. Because I have a J1772 cable for my Roadster, if I can have a J1772 output from my 80 Amp HPWC, I can use that with the J1772 Roadster cable to charge the Roadster at 70 Amps. On the other hand, I don't want to give up the Model S connector on the HPWC, because it is so convenient.

The conversion that I am talking about is non destructive, because I will not be changing the output cable of the HPWC, only disconnecting it and connecting it to the output of the Hydra.

After looking at all of this, I think that, although very nice, the Hydra is overly complicated for my application where I only need to charge the Model S or a J1772 car (my Roadster), but not both at the same time. I think that what I will do is connect the AC power and ground to the two cables as a simple "Y" connection and put in a toggle switch for the J1772 signaling line so that the active signal only goes to one connector at a time and the other will get a ground or an open, whichever seems to work better. I guess I could also use that toggle switch to control two 100 Amp contactors so that only one output was active at once, but because this is just for my use, that may be more complication than I need. See Lloyd's TS-70 to J1772 conversion for Lloyd's conversion of a Roadster HPC to Roadster and J1772 in parallel. I am just talking about doing this outside of the HPWC in a separate box. There is no hope of putting this all in an HPWC; it's very tight inside.

 

[mitch672]

Cottonwood, your plan is simpler, since you aren't concerned with using both the Model S connector and the J-1772 at the same time.

You could do it with the hydra, but it would require (2) 75A contactors, which cost about $120 each (I found a source for them at that price if you check my 75A OpenEVSE build). The advantage to the hydra of course is, you can use both at the same time, and if you choose not too, the unused cable is not energized. Anyway, if you need the 80A J-1772 cable from the HPWC to what ever your going to build, I have a 25' length I bought from Henry, that I never used... LMK if you are interested/can use it.

Edit: here is the link to the contactor, they are now more at $131 each
8910DPA73V09 Definite Purpose ContactorSquare D

Also, you could do this without the HPWC, however, the issue would be finding the 80A Tesla model S connector/cable... As far as I know, tesla doesn't sell it separately.
Here is what my 75A OpenEVSE looks like, you would only need a 2nd contactor and the hydra instead of the OpenEVSE controller:

https://code.google.com/p/open-evse/wiki/75AOpenEVSE

 

[nsayer]

After looking at all of this, I think that, although very nice, the Hydra is overly complicated for my application where I only need to charge the Model S or a J1772 car (my Roadster), but not both at the same time. I think that what I will do is connect the AC power and ground to the two cables as a simple "Y" connection and put in a toggle switch for the J1772 signaling line so that the active signal only goes to one connector at a time and the other will get a ground or an open, whichever seems to work better. I guess I could also use that toggle switch to control two 100 Amp contactors so that only one output was active at once, but because this is just for my use, that may be more complication than I need. See Lloyd's TS-70 to J1772 conversion for Lloyd's conversion of a Roadster HPC to Roadster and J1772 in parallel. I am just talking about doing this outside of the HPWC in a separate box. There is no hope of putting this all in an HPWC; it's very tight inside.

I strongly recommend that you do not simply connect both sets of hot pins together such that a disconnected plug is energized. I see truly spectacular opportunities for disaster in that direction.

A switch that's capable of safely switching that much power from one plug to another is probably not going to be that much cheaper than a pair of contactors. Once you've gone down the road of using a pair of contactors, the Hydra is really not that much further along...

Also, if you don't want to charge both cars simultaneously, the Hydra does have a sequential mode. The great benefit there is that when one car finishes, the pilot will be automatically given to the other car immediately. No manual intervention required.

 

[Cottonwood]

I strongly recommend that you do not simply connect both sets of hot pins together such that a disconnected plug is energized. I see truly spectacular opportunities for disaster in that direction.

A switch that's capable of safely switching that much power from one plug to another is probably not going to be that much cheaper than a pair of contactors. Once you've gone down the road of using a pair of contactors, the Hydra is really not that much further along...

Also, if you don't want to charge both cars simultaneously, the Hydra does have a sequential mode. The great benefit there is that when one car finishes, the pilot will be automatically given to the other car immediately. No manual intervention required.

If this were in a public location, there could be arguments about not energizing both cable with 240 Volt AC. However as Lloyd has pointed out in Lloyd's TS-70 to J1772 conversion, the risk of an energized J1772 plug, a Roadster plug, or an MS plug is very slight. The risk is very similar to a 14-50 receptacle in a garage or a live 14-50 extension cord used in an RV Park. To make contact with the hot, 240 Volt connections requires probing into the connector; simply dropping a conductor onto one of these plugs, dropping one of these plugs on a conductor, or putting one of these plugs in your hand creates an extremely small, nearly non-existent, risk.

If this were in a public location and not my garage, then I would consider going your route to allow convenient resource sharing, and use the hydra board, but I agree with Lloyd, in a private location, parallel is a reasonable, safe solution. OTOH, using the hydra could be fun! Thanks for all of your hard work!

 

[nsayer]

If this were in a public location, there could be arguments about not energizing both cable with 240 Volt AC. However as Lloyd has pointed out in Lloyd's TS-70 to J1772 conversion, the risk of an energized J1772 plug, a Roadster plug, or an MS plug is very slight. The risk is very similar to a 14-50 receptacle in a garage or a live 14-50 extension cord used in an RV Park. To make contact with the hot, 240 Volt connections requires probing into the connector; simply dropping a conductor onto one of these plugs, dropping one of these plugs on a conductor, or putting one of these plugs in your hand creates an extremely small, nearly non-existent, risk.

I still can't approve of such a configuration, but if you're going to do it, then at the very least, make sure that none of the hot lines bypass the GFI system. At least that way if any moisture creates a path to ground there will be some protection.

 

[TonyWilliams]

The Clipper Creek HPC is really easy to convert to a J1772 plug. I made this conversion with a Clipper Creek for the old BMW MiniE.

The old (yes, 2008 is old in the EV world) BMW MiniE configured Clipper Creek is only a 30 amp EVSE with a 65 amp relay, so you would need a larger relay for higher power installs up to 80 amps. The BMW proprietary car connector had been removed, but the really nice shielded wires were attached. I planned to use that as my power cord and I got a new ITT brand 75 amp rated J1772-2009 connector and wires (about $250, no longer available).

I had sent out the mother board to be reprogrammed from 30 amps to 40 amps (about $50). This had a one week turn around. It came with a new sticker to identify the box as modified to 40 amp continuous service.

I bought a new Leviton NEMA 6-50P plug to put on the power cord ($15). Since I got the unit for free, my total expense is $315 to modify it. This is a great project, since it recycles something that might have been discarded, it only requires very simple hand tools, and only takes a few hours:

The inside of the EVSE has a simple schematic:

I took everything out of the box and cleaned it. There was plenty of lose bits floating around in there. Then I installed the power cord with its new plug, and installed the J1772 cable. Since this is a bit larger than the original one, I had to make the inlet hole bigger with a file. The same was true of the power cord inlet; this cable was bigger than the original hole.

The ribbon wire in the box goes to the mother board.

- - - Updated - - -

... be finding the 80A Tesla model S connector/cable... As far as I know, tesla doesn't sell it separately.
Here is what my 75A OpenEVSE looks like, you would only need a 2nd contactor and the hydra instead of the OpenEVSE controller:

No, Tesla doesn't sell parts like that. Also, there aren't any J1772 plugs rated at either 70, 75 or 80 amps on the market anymore (ere never were 80 amp rated ones).

We may offer that in the coming months, however the market is virtually non-existent. It would be expensive.

 

[nsayer]

No, Tesla doesn't sell parts like that. Also, there aren't any J1772 plugs rated at either 70, 75 or 80 amps on the market anymore (ere never were 80 amp rated ones).

eMotorWerks sells 60A rated ones. They are 2x6, 1x8 and 2x18 gauge. I used them for the Mega-Hydra.

 

[mitch672]

I think all of the Model S owners with dual chargers bought all of the remaining 75A ITT J-1772 cables, that's one of the few applications for them, with the Tesla Model S to J-1772 adapter (which every Model S comes with). Myself and Chris Howell have assisted a few high current OpenEVSE builders, costwise it's $500 less than the Tesla HPWC, if you can find the high current J-1772 cables anywhere.

I just completed a 40A OpenEVSE with the Model S connector and 40A cable I bought from Tony/EV Quick Charge (hooked up the 3.3V so the button opens the door too), testing Chris's new European OpenEVSE that can run 240V contactor coils directly. I'll post some links to pictures when in get them up. Don't mean to hijack the Hydra thread, but it's all sort-of related.

 

[Cottonwood]

I strongly recommend that you do not simply connect both sets of hot pins together such that a disconnected plug is energized. I see truly spectacular opportunities for disaster in that direction.

A switch that's capable of safely switching that much power from one plug to another is probably not going to be that much cheaper than a pair of contactors. Once you've gone down the road of using a pair of contactors, the Hydra is really not that much further along...

Also, if you don't want to charge both cars simultaneously, the Hydra does have a sequential mode. The great benefit there is that when one car finishes, the pilot will be automatically given to the other car immediately. No manual intervention required.

I still can't approve of such a configuration, but if you're going to do it, then at the very least, make sure that none of the hot lines bypass the GFI system. At least that way if any moisture creates a path to ground there will be some protection.

Here is another solution. Use a generator transfer switch to select which cable gets the output of the HPWC. See Amazon.com : Generac 6334 100-Amp Manual Transfer Switch Single Load for Portable Generators as an example. Of course, I would leave the GFCI circuits enabled in the HPWC; there is no reason to disconnect them and only liability to be gained if I do so.

I could then use a 240 Volt Coil SPDT relay like this to only enable the pilot on the correct cable. Honeywell R4222L1015 SPDT Power Relay 9727 | eBay

I understand that this does not get me the auto switching/sharing of the Hydra, but for my limited needs application, it is far simpler.

 

[nsayer]

You can't use a relay to switch the pilot like that because the hot lines are not energized until a few steps through the handshake. Chicken, meet egg.

You can use a manual switch, but then you must insure you keep the transfer switch and pilot switch in sync. The implications for a mistake are powering the wrong plug, which has safety implications that prevents me from endorsing the idea.

What you could get away with is a pair of contactors switched on and off with a DPDT switch that also switches the pilot line from one plug to another. I can just get behind that idea. I would strongly recommend 24 volt contactors for that application powered by a separate transformer so that the DPDT switch wiring would all be low-voltage.

 

[mitch672]

That manual transfer switch is already the cost of 1 high power contactor, when you get all done with it, well, we have an expression, it'll be a "Rube Goldberg"

Rube Goldberg machine - Wikipedia, the free encyclopedia
Rube Goldberg - Wikipedia, the free encyclopedia

You can get away with a lot, the question begs, should you? I wouldn't, not with life saftey equipment, which is all an EVSE is.

 

[hcsharp]

...
My reason for this is to get 70 Amp charging for my Roadster from my HPWC. Tesla makes a Roadster Connector to Model S adapter, but they do not make a Model S to Roadster adapter. Because I have a J1772 cable for my Roadster, if I can have a J1772 output from my 80 Amp HPWC, I can use that with the J1772 Roadster cable to charge the Roadster at 70 Amps. On the other hand, I don't want to give up the Model S connector on the HPWC, because it is so convenient.
...

I have native Roadster connectors if that helps, and 80A EVE cable that I can crimp onto it. I no longer sell just the cable but if you buy a connector I'll sell some cable to go with it. You could then charge both your Roadster and Model S using their native connectors which is more convenient. If you had the Hydra setup or something similar that you are thinking of you could charge both cars from the same charger.

BTW I agree with nsayer that the hydra does not add much complexity and adds a lot of convenient features. I agree with you that safety is not much of an issue but convenience is.

 

[nsayer]

That manual transfer switch is already the cost of 1 high power contactor, when you get all done with it, well, we have an expression, it'll be a "Rube Goldberg"

To be fair, the two contactor + DPDT solution isn't so outlandish that I'd call it Rube Goldberg-esque. Not when I'm hawking Hydra boards, certainly.

However, the distance between that solution and the Hydra is only about $150.

You can get away with a lot, the question begs, should you? I wouldn't, not with life saftey equipment, which is all an EVSE is.

I dunno if I'd call an EVSE a "life safety" device. That implies that it's a device whose continued correct operation is vital to someone's survival - like a nuclear plant or an aircraft engine. An EVSE is a device that poses a potential hazard if it malfunctions, but that's not any different than a toaster-oven or a hair dryer. If you can yank the plug out of the wall and the world doesn't end, it's not a "life safety" device, I don't think.

 

[mitch672]

EVSE = Electric Vehicle Safety Equipment

To disengage and engage the AC mains, safely and protect the user from exposure to hazardous voltage.

That's the basic definition.. OpenEVSE and Hydra accomplish that, and have gfi checks, and communicate to the vehicle.
They also disengage power when the plug is removed. You can build anything you want with relays, contactors, DPDT switches, but my point is, it's just easier to do it correctly, and keep all of the systems intact.

 

[nsayer]

I think it is Electric Vehicle Supply Equipment.

 

[mitch672]

I think it is Electric Vehicle Supply Equipment.

Probably is. I think starting with the HPWC only gets you the cable and special Model S connector, and it's far too pricey for just that.
If the high power J-1772 cables where still availble, the dual high power Hydra could be built cost effectively.

if Tesla where to sell the high power connector/cable assembly for a reasonable price, then this would be doable for a reasonable cost. It's just difficult to get high power cables and connectors for a reasonable prices these days, and, sometimes not availble for any price.

 

[nsayer]

Probably is. I think starting with the HPWC only gets you the cable and special Model S connector, and it's far too pricey for just that.
If the high power J-1772 cables where still availble, the dual high power Hydra could be built cost effectively.

if Tesla where to sell the high power connector/cable assembly for a reasonable price, then this would be doable for a reasonable cost. It's just difficult to get high power cables and connectors for a reasonable prices these days, and, sometimes not availble for any price.

One issue with higher powered Hydras is that the inlet wiring can only be 6 AWG or smaller to fit through the GFI coil. I haven't found an alternative part for that - and 6 gauge is quite a squeeze.

That will get you 75A input. With the 60A cables from eMotorWerks, that would yield a 36A/60A Hydra with a 90A breaker and circuit. That's awfully beefy if you ask me.

 

[mitch672]

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

 

[Cottonwood]

Hey, sorry to have stirred up so much emotion on this friendly thread where we are just trying to help each other and teach each other how to do things well.

I have the benefit of plenty. I also have the joy and curse of living in two locations. I own an MS that lives mostly in Pagosa Springs; I own a Roadster that lives mostly in Boulder. I usually fly my small plane between the two places. However, the MS migrates to Boulder and the Roadster migrates to Pagosa over the continental divide. A 70 Amp J1772 EVSE at Wood's High Mountain Distillery helps with both of these migrations!

Pagosa has an HPWC for the MS that puts out 80 Amps from a 100 Amp Circuit Breaker (CB). In addition, Pagosa has a 14-50 for the MS or Roadster on a 50 Amp CB.

Boulder has an 80 Amp HPWC on a 100 Amp CB, a 70 Amp Roadster HPC on a 90 Amp CB, as well as a 14-50 on a 50 Amp CB.

I have all the charging capacity that I need 99% of the time in both places. However I am the Obsessive Optimizer and retired engineer who always wants more. As an example, in a time long, long ago, when I was told that I could turn up the 14 GHz HPA driving a 5 meter dish pointed at a geostationary satellite to 30 dBW, I was drooling... (for those geeks that understood that, you have me calibrated :smile

This has led me to figure out how to get 70 Amp charging for the Roadster in Pagosa.

I got the 75 Amp J1772 cable from Clipper Creek as an upgrade for my TS-70/CS90 HPC to convert it to J1772. This does not help me much because I already have 80 Amp charging for the MS and 70 Amp charging for the Roadster in Boulder. I also have 70 Amp J1772 to Roadster adapter in my bag of tricks. Therefore if I put the 75 Amp J1772 cable on the CS-90 HPC in Boulder, I would have a 70 Amp Roadster cable to work with. If I then had a way to parallel the now available 70 Amp Roadster cable with the 80 Amp MS cable on the HPWC in Pagosa, I would have full power charging everywhere.

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.

I trust the safety of a 14-50 receptacle or a 14-50 extension cord. A live J1772, MS, or Roadster plug is very similar. Therefore, I am inclined to put the 75 Amp J1772 cable on the CS-90 in Boulder, and then put the 80 Amp MS cable in parallel with the 70 Amp Roadster cable in Pagosa.

Do any of you have suggestions on how to do this better, or arguments with substantive reasoning on why what I suggest is a danger over a live, 14-50 extension cord used in RV Parks today?

Please read Lloyd's TS-70 to J1772 conversion where Lloyd explains the risk of an energized J1772 plug or a Roadster plug is very slight, and Clipper Creek provides an implicit agreement.

As I said above, all I want is to learn from each other, and help each other... OTOH, let's not get into religious wars based on precedent set by obsessive standards committees.

 

[mitch672]

If your going to do it manually, I could suggest you wire the AC output of the EVSE into a small 6 circuit 100A breaker panel. Then use a 70A 2 pole breaker to connect the Roadster cable, and use an 80A 2 pole breaker for the Model S cable. You manually turn on only a single breaker at once, and clearly label them. Home Depot has small SquareD Homeline 6 circuit 100A panels for $20, you should be able to buy 70A and 80A 2-pole Homeline breakers for $35 each or so (or you could just use 100A breakers as well, since your only using them for switching), so under $100 to keep just a single cable energized. I suppose you can just connect the Pilots together. The small circuit breaker panel also gives you a place to strain relief the cables and make all of the AC connections in, and connect the grounds etc. I'd rather see you build a proper dual contactor Hydra, but do what you will.

SquareD 100A Homeline breakers, $34 at Home Depot:
http://t.homedepot.com/p/Square-D-by-Schneider-Electric-Homeline-100-Amp-Two-Pole-Circuit-Breaker-HOM2100CP/100156187

SquareD 100A 6-circuit Homeline panel, $20 at Home Depot:
Square D by Schneider Electric, Homeline 100 Amp 6-Space 12-Circuit Indoor Surface Mount Main Lugs Load Center with Cover, HOM612L100SCP at The Home Depot - Tablet