Charging X and S

[napabill]

Looks like I'm about to have two Tesla's when my Model X is delivered. I don't think my electrical panel will allow a 2nd 14-50 line, so was thinking I could use timed charging so that both wouldn't be charging at the same time. We have TOU billing in Calif, so use timed charging anyway. I'm thinking setting one car up to charge from 12 to 4, and the other from 4 to 8. Most days that will be plenty. Would like to be able to schedule OFF, but don't think that is available. Suppose VisibleTesla might do it.

 

[CaliX]

Looks like I'm about to have two Tesla's when my Model X is delivered. I don't think my electrical panel will allow a 2nd 14-50 line, so was thinking I could use timed charging so that both wouldn't be charging at the same time. We have TOU billing in Calif, so use timed charging anyway. I'm thinking setting one car up to charge from 12 to 4, and the other from 4 to 8. Most days that will be plenty. Would like to be able to schedule OFF, but don't think that is available. Suppose VisibleTesla might do it.

Here in LA you can have DWP pull in a second line at a discounted rate for PM only to cover all your needs and it's rebated. Maybe your utility has something similar there. I am in the process now cause I have a S and soon to have a X.

 

[GSP]

The "open EVSE" people plan to offer a two car EVSE. Just plug in both cars, and it automatically would charge one, then the other. Optionally it could split the available current between the two cars, charging both at half speed until one finishes. After that it could automatically ramp the remaining car up to full charging speed. I have no idea when this will be available, but likely not soon enough.

Another option would be to convert an electric appliance to natural gas to free up capacity for a second 14-50.

Yet another option would be to install a 6-20 outlet if your panel could manage adding a 20 Amp breaker. You could use Tesla's 5-20 adapter to get the proper 16 A pilot signal. You also would need a 6-20 to 5-20 adapter.

Good Luck,

GSP
GSP

 

[[email protected]]

Gonna charge both X and S on same circuit....

All: Have an antique 100amp Zinsco panel....we have an electric range, oven, dryer, washer and DW....moved in in 2007, and added 16 240w Phono panels/Solar Edge inverter, and then an S and (coming soon?) an X. So, panel is humming w/PV amps feeding the grid during the day and presently drawing between midnight and 6 a.m. on average 50 miles for the S per day (about .318 wh per mile over 32K miles, so 15.9 kwh per day). When X comes, will add another 20 miles per day (at about .400 kwh per mile or 8 kwh). Our plan is to add a receptable to the present 50 amp circuit, and time the cars to charge serially to avoid overload and tripped breaker (with a Zinsco, who knows?)
...I have posted Tesla twice with the suggestion that the cars should exchange charging info to prevent simultaneous charging (and overload)...crickets to date. J S 41448

The "open EVSE" people plan to offer a two car EVSE. Just plug in both cars, and it automatically would charge one, then the other. Optionally it could split the available current between the two cars, charging both at half speed until one finishes. After that it could automatically ramp the remaining car up to full charging speed. I have no idea when this will be available, but likely not soon enough.

Another option would be to convert an electric appliance to natural gas to free up capacity for a second 14-50.

Yet another option would be to install a 6-20 outlet if your panel could manage adding a 20 Amp breaker. You could use Tesla's 5-20 adapter to get the proper 16 A pilot signal. You also would need a 6-20 to 5-20 adapter.

Good Luck,

GSP
GSP

 

[FlasherZ]

All: Have an antique 100amp Zinsco panel....we have an electric range, oven, dryer, washer and DW....moved in in 2007, and added 16 240w Phono panels/Solar Edge inverter, and then an S and (coming soon?) an X. So, panel is humming w/PV amps feeding the grid during the day and presently drawing between midnight and 6 a.m. on average 50 miles for the S per day (about .318 wh per mile over 32K miles, so 15.9 kwh per day). When X comes, will add another 20 miles per day (at about .400 kwh per mile or 8 kwh). Our plan is to add a receptable to the present 50 amp circuit, and time the cars to charge serially to avoid overload and tripped breaker (with a Zinsco, who knows?)
...I have posted Tesla twice with the suggestion that the cars should exchange charging info to prevent simultaneous charging (and overload)...crickets to date. J S 41448

I wouldn't charge one car on a Zinsco, much less two. Just my opinion, but those boxes have proven to be time bombs again and again. And I would never, never, never, never, NEVER purposely introduce the chance of an overload on a Zinsco box (2 receptacles on one circuit) - there is a high chance that the breaker simply won't trip. Please don't do what you're proposing.

NEC 2014 added a new section 210.17 that states an outlet (which includes 50A receptacles) for electric vehicle charging shall be on a dedicated branch circuit with no other outlets. You may run into issues with inspections on that one.

As for the exchanging charging information, I think Tesla's starting to see more dual-Tesla households with S and X... I wouldn't be surprised if we saw something that allowed multiple cars to share.

 

[rick]

I'm in the same boat. 2013 S85 on a 50 amp circuit with a 14/50 line. No problems. I only drive it 15,000 m/yr. & don't charge it every day. Soon to add a Model X with a 72 amp charger. House is 100 yrs old but does have 200 amp service. It will be difficult to upgrade. I was just going to add another 14/50 outlet to the other side of the garage and only charge one car at a time--or time it so they don't overlap. If FLASHERZ is right I might have code issues with that. Obviously you want to err on the side of safety. I talked to an electrician but I'm not sure that he understands the complexity of the situation. I called Tesla sales with questions about it and got the stock answer----"hire an electrician". Any suggestions?

 

[S-dog]

John F, please do yourself a favor and replace the Zinsco panel. I see where most electricians get replacement breakers for them and its not pretty. The breakers just don't trip. Its like putting a nail in a fuse holder. A 3 alarm fire waiting to happen.

 

[ohmman]

John F, please do yourself a favor and replace the Zinsco panel. I see where most electricians get replacement breakers for them and its not pretty. The breakers just don't trip. Its like putting a nail in a fuse holder. A 3 alarm fire waiting to happen.

I will second this. I replaced ours shortly after we moved in for exactly this reason. Once we got the breakers out, you could see where the panel was chewed up from the arcing that was occurring behind them.

Replacing these ubiquitous panels is strongly recommended.

 

[FlasherZ]

I'm in the same boat. 2013 S85 on a 50 amp circuit with a 14/50 line. No problems. I only drive it 15,000 m/yr. & don't charge it every day. Soon to add a Model X with a 72 amp charger. House is 100 yrs old but does have 200 amp service. It will be difficult to upgrade. I was just going to add another 14/50 outlet to the other side of the garage and only charge one car at a time--or time it so they don't overlap. If FLASHERZ is right I might have code issues with that. Obviously you want to err on the side of safety. I talked to an electrician but I'm not sure that he understands the complexity of the situation. I called Tesla sales with questions about it and got the stock answer----"hire an electrician". Any suggestions?

I don't know that there are any other suggestions.

The best thing to do is to install a second circuit, if it's possible in the load calculations. It's the most legal and will result in the least amount of inspector headaches.

The next best thing that I advise others to do is to install a subpanel in the garage. You can use the original circuit's cable as a feeder to a new small subpanel, something like a GE PowerMark Gold 125 Amp 4-Space 8-Circuit Single-Phase Indoor Main Lug Circuit Breaker Panel-TL412CP - The Home Depot. Then use two 50-amp breakers to pull a branch circuit to each receptacle. You can try to rely upon 220.60, the non-coincident loads rule - which says if it is unlikely that two loads will be in use simultaneously, you size only for the larger of the two. I've found that some inspectors won't let you do this because of the lack of an interlock preventing both from drawing the current at the same time, but many / most will. It re-uses your "home run" to the panel; and, with #6 NM cable you can upsize the feeder breaker to 60A (max 55A load) with NM cable or even 70A (max 65A load) with conduit + THHN.

I'll just reiterate here that I would not do this with a Zinsco or FPE panel, though...

 

[Rocky_H]

One other thing if you really don't have any more allowed current capacity is that you could split out the 50A line into two circuits that total 50A or less--maybe a 6-20 outlet and a 14-30. Then, you could run both at the same time, with no scheduling worries. Each will obviously be slower than a 14-50, but if you've got all night, it shouldn't be a problem.

 

[[email protected]]

Tesla 50 amp restriction

Thanks for the Zinsco comments and concerns...my 57 year old busses and breakers are spotless and the breakers trip when tested, so gonna leave them in service for a bit longer (the enclosure is tiny, and Cutler does not yet make a retro kit for such a tiny enclosure). As good as Cutler? No. Mediocre design and failure history? Yes. But in good condition without observed failure modes? Yes. But forget all that about power delivery at panel: the big question that I share with others: single 50 amp dedicated circuit, and, soon, two vehicles (S & X) to charge. The simple solution: use one receptacle, and move the cars to charge as needed. The problem is Lisa and I will be all in with the X: we are selling our last ICE cars, and will only have Teslas, so sometimes, we need both cars range charged. Am I switching cars at 4 in the morning? no. More complicated solution: add second receptacle to single circuit, and ensure that cars charge in series at 40 amps or concurrently with amperage limited jointly to max 40 amps. No need to move cars, and the midnight-6 am window should charge both cars (although a fully depleted S can take us past 6....) I get that the receptacles imply the ability to overload if the cars are commanded to charge at the same time. And if both cars charge at more than 50 amps combined, the breaker should trip though it would be better if the cars could coordinate charging to avoid overload. An excellent solution would be Tesla limiting the max charge rate for multiple cars to a defined amount (40 amps?), and coordinating the charge rate between multiple cars. MTCents John

 

[napabill]

Really hope TM allows for the linking of two owned Tesla's so that coordinated charging can be done. I suppose for now I'll use reduced amps for each totaling 40 on a scheduled basis. Pretty sure the S will be more of a daily driver, so would likely need more regular charging.

 

[FlasherZ]

Thanks for the Zinsco comments and concerns...my 57 year old busses and breakers are spotless and the breakers trip when tested, so gonna leave them in service for a bit longer (the enclosure is tiny, and Cutler does not yet make a retro kit for such a tiny enclosure). As good as Cutler? No. Mediocre design and failure history? Yes. But in good condition without observed failure modes? Yes. But forget all that about power delivery at panel: the big question that I share with others: single 50 amp dedicated circuit, and, soon, two vehicles (S & X) to charge. The simple solution: use one receptacle, and move the cars to charge as needed. The problem is Lisa and I will be all in with the X: we are selling our last ICE cars, and will only have Teslas, so sometimes, we need both cars range charged. Am I switching cars at 4 in the morning? no. More complicated solution: add second receptacle to single circuit, and ensure that cars charge in series at 40 amps or concurrently with amperage limited jointly to max 40 amps. No need to move cars, and the midnight-6 am window should charge both cars (although a fully depleted S can take us past 6....) I get that the receptacles imply the ability to overload if the cars are commanded to charge at the same time. And if both cars charge at more than 50 amps combined, the breaker should trip though it would be better if the cars could coordinate charging to avoid overload. An excellent solution would be Tesla limiting the max charge rate for multiple cars to a defined amount (40 amps?), and coordinating the charge rate between multiple cars. MTCents John

I understand your desire and the challenges, I deal with them often. Tesla doesn't offer a sharing option yet. Personally, I'd recommend doing it right (replacing the Zinsco panel and using two branch circuits, or using the existing circuit as a feeder and placing a subpanel as I mentioned above) -- that may not persuade you, and I can't force you, so should you continue, I wish you the best.

The 210.17 rule (an EV charging outlet requires individual branch circuit with no other [connections]) is a new rule in NEC 2014 and hasn't been tested much yet with inspectors; I might try to make a technical argument that it is legal to have two receptacles because both of them are for EV charging and only get used non-coincidentally. Some jurisdictions won't let that fly and err on the side of doing more work for safety reasons; e.g., I know of a case where Los Angeles city inspector chiefs disallowed an HPWC on a circuit less than 100A even though it was configured with DIP switches correctly and Tesla's manual says that it can. The argument was that Tesla's nameplate shows a max current of 100A (after continuous load factor) and therefore it required a 100A circuit.

One final word on the Zinsco buses from my personal experience: the worst thing about them is that the removal of the breakers to inspect the buses can be the very act that causes them to start arcing under high loads (because the breaker contacts spread). This makes the Zinsco a chicken-and-egg problem. You can't inspect the buses without doing the very thing that causes arcing - spreading the breaker contacts. When a home inspector refers an owner to an electrician because Zinsco panels exist, many electricians won't even inspect the panel and will give you a straight recommendation to replace the panel -- even if they're not the ones who would profit from the work. I argue that no Zinsco panels out there are in "good condition", even kept in the best conditions. They are that bad. And I'm not the only one with this experience: Anyone receive a 14-30 adapter yet? - Page 3

The same scenario happened with my FPE panel in my California home. Many times the failure mode of the FPE breakers were that they would trip under overload conditions, but only once. That trip would jam the mechanism inside. Subsequent trips wouldn't occur, and in many cases the breaker contacts were still closed even when the handle was "off". My home nearly burned because of a faulty FPE breaker - as the walls were ripped open to expose the melted wiring, it was clear that within 15 minutes I would have had a call to the fire department. I was lucky to be home at the time.

You can do what you'd like but I will never recommend charging 1 car, much less 2, from a Zinsco or FPE panel. It is that dangerous.

 

[[email protected]]

I understand your desire and the challenges, I deal with them often. Tesla doesn't offer a sharing option yet. Personally, I'd recommend doing it right (replacing the Zinsco panel and using two branch circuits, or using the existing circuit as a feeder and placing a subpanel as I mentioned above) -- that may not persuade you, and I can't force you, so should you continue, I wish you the best.

The 210.17 rule (an EV charging outlet requires individual branch circuit with no other [connections]) is a new rule in NEC 2014 and hasn't been tested much yet with inspectors; I might try to make a technical argument that it is legal to have two receptacles because both of them are for EV charging and only get used non-coincidentally. Some jurisdictions won't let that fly and err on the side of doing more work for safety reasons; e.g., I know of a case where Los Angeles city inspector chiefs disallowed an HPWC on a circuit less than 100A even though it was configured with DIP switches correctly and Tesla's manual says that it can. The argument was that Tesla's nameplate shows a max current of 100A (after continuous load factor) and therefore it required a 100A circuit.

One final word on the Zinsco buses from my personal experience: the worst thing about them is that the removal of the breakers to inspect the buses can be the very act that causes them to start arcing under high loads (because the breaker contacts spread). This makes the Zinsco a chicken-and-egg problem. You can't inspect the buses without doing the very thing that causes arcing - spreading the breaker contacts. When a home inspector refers an owner to an electrician because Zinsco panels exist, many electricians won't even inspect the panel and will give you a straight recommendation to replace the panel -- even if they're not the ones who would profit from the work. I argue that no Zinsco panels out there are in "good condition", even kept in the best conditions. They are that bad. And I'm not the only one with this experience: Anyone receive a 14-30 adapter yet? - Page 3

The same scenario happened with my FPE panel in my California home. Many times the failure mode of the FPE breakers were that they would trip under overload conditions, but only once. That trip would jam the mechanism inside. Subsequent trips wouldn't occur, and in many cases the breaker contacts were still closed even when the handle was "off". My home nearly burned because of a faulty FPE breaker - as the walls were ripped open to expose the melted wiring, it was clear that within 15 minutes I would have had a call to the fire department. I was lucky to be home at the time.

You can do what you'd like but I will never recommend charging 1 car, much less 2, from a Zinsco or FPE panel. It is that dangerous.

FLasherZ: Wanted to circle around and thank you for the comments: we do not see eye to eye, and I have found I learn the most from people who dispute my ideas. I thank you for adding, not detracting, from my thoughts. Best, John in Santa Rosa

 

[Jason S]

With a 200 mile range even in relatively bad weather, why not just charge one or the other every other day? Personally I'm within 40 miles on most days, so skipping a couple days is no big deal.
Heck, the plain old wall socket worked for me for the first 6 months of ownership because I wasn't driving much on weekends.

 

[cwerdna]

The "open EVSE" people plan to offer a two car EVSE. Just plug in both cars, and it automatically would charge one, then the other. Optionally it could split the available current between the two cars, charging both at half speed until one finishes. After that it could automatically ramp the remaining car up to full charging speed. I have no idea when this will be available, but likely not soon enough.

Along these lines, J1772 Hydra - charge two vehicles with one charger has existed for awhile.