Charging 120v vs 240v efficiency

[Rocky_H]

I take back my post. I now only recommend installing a pair of J-1772 chargers that has way more features and load sharing as well as being compatible with any other EV.

Yeppers. Clipper Creek now has a very nice dual-headed station.
HCS-D40 Dual Charging Station| Level 2 | ClipperCreek

 

[stonelance]

Well, you USED to be able to do that with the version2 wall connectors. Tesla made the boneheaded, idiotic, moronic, short-sighted, infuriating, pathetic decision to replace the version2 with the version3 that does not have this most used feature!!!!!! They say that they plan to implement that at some unknown point in the future with a software update!

Well that is annoying. I assumed that was the main point of making it WiFi would be to allow sharing power without the communication line. I guess they also used the over the air update as an excuse to not support power sharing in the initial software

 

[jsrawa]

To follow up on the conversation our house is finally at the electrical stage and the electrician ran some calculations and thinks it is too much load to have two 60amp, therefore they were recommending only one.

I’m just really at a loss of what to do. I have one HPWC I received as a referral gift. I also anticipate another Tesla in the future. Should I keep the 60amp line and have it go to the one HPWC for now and then when we get another Tesla either daisy chain or break it into two 30amp circuits at a later date? Should I up the one to higher than 60amp then? Is there a NEMA receptacle for higher than 60amp? Appreciate the recs!!

 

[brkaus]

To follow up on the conversation our house is finally at the electrical stage and the electrician ran some calculations and thinks it is too much load to have two 60amp, therefore they were recommending only one.

I’m just really at a loss of what to do. I have one HPWC I received as a referral gift. I also anticipate another Tesla in the future. Should I keep the 60amp line and have it go to the one HPWC for now and then when we get another Tesla either daisy chain or break it into two 30amp circuits at a later date? Should I up the one to higher than 60amp then? Is there a NEMA receptacle for higher than 60amp? Appreciate the recs!!

I do fine with a single Gen 2 WC and 2 Teslas and a leaf. But this will totally depend on your driving situation.

I would wire both locations for 60a and just put in a breaker for one. I would pull the appropriate wiring between the two locations for the control of the two WCs daisy chained (the Gen3 do not require a wire, but the feature isn't yet released).

You can still limit the total current of both WCs and wire them both back to the panel each on their own 60A breaker. The control circuit will ensure the two do not exceed the programmed amount - and that is what matters in terms of house load calculations.

 

[DaveG_NJ]

Since you already have the one 60A circuit run to the garage, it would be relatively cheap to have an electrician interrupt that line there in the garage with a small small sub-panel and split it to two 30A circuits on each side of your garage, or maybe 40A and 20A if you think one car will need more charging than the other most of the time.

I like that idea - kinda like Regular or Hi-test. LOL. For me, it's all about convenience. I could, with enough disciplined driving and controlled charging, eek through the week on 15A. But then there's life ... and detours, and weather, and unplanned errands and suddenly, my pristine plan is shot. I installed a 14-50 on a nearly 100' run to my garage at a cost of about 3 years worth of SuperCharging. I want to be able to charge up in one night, which I can and not worry about -- or change my driving.

 

[AlanSubie4Life]

To follow up on the conversation our house is finally at the electrical stage and the electrician ran some calculations and thinks it is too much load to have two 60amp, therefore they were recommending only one.

I’m just really at a loss of what to do. I have one HPWC I received as a referral gift. I also anticipate another Tesla in the future. Should I keep the 60amp line and have it go to the one HPWC for now and then when we get another Tesla either daisy chain or break it into two 30amp circuits at a later date? Should I up the one to higher than 60amp then? Is there a NEMA receptacle for higher than 60amp? Appreciate the recs!!

I don't see any reason to go higher than 60A unless you're planning on a Cybertruck (maybe - and even then it probably doesn't matter THAT much). 48A is the maximum for Model 3 (Cybertruck will nearly certainly be higher). Like I said, even for Cybertruck 11.5kW is probably going to be fine nearly all the time (with a Cybertruck ~180kWh battery it'll be a 14-hour charge to 100%). So no reason to go higher than 60A, unless you have a legacy vehicle with 20kW charger option.

I would ask the electrician what is the maximum load that the load calculations support, and just install one 60A and then allocate the remaining balance to the other one. Or if that ends up being just 10A or something, just reduce the 60A to 40A or something, or whatever distribution you feel is best. (I would tend to try to max out one of them just so you have that option.)

240V/20A is perfectly fine in nearly all situations. And if you have a 60A charger as well, it really won't matter. I'm sure that one vehicle will be the one that "typically" needs the most charging. And if you really have to you, you can always switch spots on the rare occasion where the one that needs the fast charge isn't in the right spot.

Better option if you're just doing hard-wired WCs: Two Wall Connectors can also do communication, so you can also do a maximum rate circuit, max that load calcs support, and just let them arbitrate on the same circuit. I can't remember why that wasn't the original solution here (haven't gone back to read the thread).

Obviously that doesn't work if for some reason you want a J-1772 or want that option in the future (unless in the future J-1772 EVSEs also can communicate - which it seems like they will at some point but undoubtedly there will be no uniform comm standard, so it will just be all stupid and you won't be able to mix and match).

EDIT: reading back on this thread, it looks like Tesla is also being all stupid about this with V3. Anyway, obviously load-sharing is the best option, but if you can't do that, just allocate sensibly and max out the load capability according to the load calc from the electrician. Have him figure out the maximum allowed.

 

[Rocky_H]

I’m just really at a loss of what to do. I have one HPWC I received as a referral gift. I also anticipate another Tesla in the future. Should I keep the 60amp line and have it go to the one HPWC for now and then when we get another Tesla either daisy chain or break it into two 30amp circuits at a later date?

I think a lot of people get too obsessed with going beyond over the top with charging circuits. 30 and 40 amp circuits are very capable for at home charging and are not bad at all. I wouldn't stress on that a bit having two 30A circuits. That's great. If you want to future proof a bit in an easy way, you can certainly do the wiring runs with a little bit thicker than that needs right now, since that is the labor intensive expensive part. Then later, if you need to swap some things a bit, it's cheap and simple to replace the breakers and the ends by swapping outlets for wall connectors.

Should I up the one to higher than 60amp then?

I don't see any point in that. Tesla has decided they are capping everything at 60A circuits from now on with their new (crummy) Gen3 wall connector not having any capability above that and discontinuing the much better Gen2, which could do higher power.

Is there a NEMA receptacle for higher than 60amp?

No, and you wouldn't want to. The mobile charging cable, which is what you would use to plug into outlets can't draw any more than 32A, so even 60A outlet types are useless for trying to get more power. You would need to go with some kind of hard wired thing to get more than 32A.

I don't see any reason to go higher than 60A unless you're planning on a Cybertruck (maybe - and even then it probably doesn't matter THAT much). 48A is the maximum for Model 3 (Cybertruck will nearly certainly be higher).

I'm pretty sure not. I think it is a terrible decision, but Tesla has indicated pretty certainly that they will not be going with anything higher than the 48A with any of their vehicles anymore. It is dumb and goes agains what their customers have been asking for, but it's the direction they have decided on. They showed that by killing the Gen2 wall connectors.

 

[AlanSubie4Life]

but Tesla has indicated pretty certainly that they will not be going with anything higher than the 48A with any of their vehicles anymore.

I guess we'll see. Doesn't make much sense for any of their current vehicles, but for a vehicle that uses nearly twice as much energy per mile, they may have to rethink things. And there's no reason they can't provide updated equipment for that in the future. Maybe they'll have dual chargeports on Cybertruck, or something. They wouldn't be the first EV with that, and it does provide versatility.

In any case, doesn't matter much for this particular issue - just want to max out the load calcs and see where things end up.

 

[user212_nr]

I also anticipate another Tesla in the future. Should I keep the 60amp line and have it go to the one HPWC for now and then when we get another Tesla either daisy chain or break it into two 30amp circuits at a later date?

If you anticipate a second Tesla, then you should use the 60A line for a sub-panel and then install the wall connector on the 60A breaker on the 60A sub-panel.

When you go to buy the second Tesla, you can either downgrade it to 30A or if load sharing is available, install both at 60A. Not that anything is wrong with 30A.

To save money, you should put in the wiring for the sub-panel and second 60A now - electricians charge most their money just for coming out for the day and the wires are relatively cheap. That is if you are sure you will get the second Tesla.

 

[Euler]

why it's really not charging efficiency but instead charging time really that is affected by 120v vs 240v.

So close, but you missed it. Change "but" to "as much as" and you'd be correct.

There *are* electrical losses that are better at higher voltage (this is why long distance power transmission is done at extremely high voltage).

The point is that the system costs of keeping the systems awake while charging are even more.

 

[Dmagyar]

I for one am glad there’s fewer 110/220 references...