Charging station for home/work

[rodmacpherson]

I will boldly forecast that several of those who now intend to charge with the UMC will wind up buying a plug in wall mounted EVSE (won't be from Tesla but there are dozens available) and so I think that should have been an option for the poll.

When I set up the poll I did set the option for anyone to add their own options.
I have added that, feel free to use it.

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[tmeyer3]

Likely the most reasonable will be to have them install a nema 14-50. I believe that will handle the 48 amps that the Tesla wall connector can pull.

Unfortunately, 50A won't let you charge at the advertised 48A max home charging. You need a full 60A breaker. It's something like 10-15%. So a nema 14-50 will actually max out at 32A. Even if you wire it up to 60A (probably shouldn't), the car will know you're plugging in to a 14-50 and cap at 32.
I only mention it because I tried it for a few months until Tesla came out to do my solar install and we added on the wall charger without extra install fees. That was the generosity of the local contractor Tesla hired, not a deal from Tesla.

 

[ajdelange]

Really you want to try to get as much capacity as possible. If you have to hire an electrician to come out to your house to install something you better be installing the most capacity you can for a reasonable cost. Likely the most reasonable will be to have them install a nema 14-50. I believe that will handle the 48 amps that the Tesla wall connector can pull.

Unfortunately, 50A won't let you charge at the advertised 48A max home charging. You need a full 60A breaker. It's something like 10-15%. .

The story is that a 14-50 can be installed behind a 40 or 50A breaker. Obviously you shouldn't plug anything that draws more than 40A into one that's behind a 40A breaker nor anything that draws more than 50 A into one that is wired behind a 50 A breaker. But you can only plug a 50A load into a 50A circuit if it is an "intermittent load" which is defined as any load which is connected for less than 3 hours unless that load is EVSE which is, by definition, not intermittent even if you plug it in for less than 10 minutes. Non intermittent loads require derating to 80%. Thus the biggest EVSE you can plug into a 50A wired outlet is 40 A and if it is wired for 40A the biggest you can plug in is 32 A. This explains the UMC's 32 amp rating. In an abundance of caution they have assumed that all 14-50R are wired to 40 A breakers and thus only allow the UMC to pull 32A from a 14-50. Other manufacturers EVSE with 14-50P plugs will allow the full 40 A.

Note that Tesla's corded charger which is hard wired with a 14-50P does allow the full 40A. Why this is I cannot explain.

So a nema 14-50 will actually max out at 32A. Even if you wire it up to 60A (probably shouldn't), the car will know you're plugging in to a 14-50 and cap at 32

The EVSE tells the car how much it can have. The corded connector is permanently to limit requests to 40A. The UMC is programmed by the other pins on the plug-in adapter. If you plug in the 14-50R adapter it programs the unit to allow no more than 32A. If you plug in the 120V 15A adapter it programs the unit to limit to 12A etc.

The HPWC is programmed through the WiFi interface. You can install an HPWC behind a 30A breaker and "commission" that HPWC for a 60A breaker in which case it will allow the car to ask for 48 A which will, of course, pop the 30A breaker.

In the future we will and are seeing very high charging capabilities. Why not have the capacity to do that at home if it’s within reason. I installed 125 amps at 220v so I can accommodate faster charging if I need it.

I believe the new Ford will take up to 80A (requiring a 100A circuit). You can install multiple Tesla HPWC on that but you will have to go through a sub-panel with a separate 60A (or smaller) breaker for each.

 

[Crissa]

Currently I am using the default OBC (on board charger) for my Zero which maxes at 1.7kW. With a custom 240v cable on a 50a circuit. The custom cable also plugs into the 30a outlet on my generator. My bike charges at about 17 miles per hour.

The vast majority of the time I only charge it once or twice a week. It is my primary form of transportation.

-Crissa

 

[HaulingAss]

Why not have the capacity to do that at home if it’s within reason. I installed 125 amps at 220v so I can accommodate faster charging if I need it. Sure most of the time I will use a lower charge rate because I have a short commute and I want to protect the battery but that day that I need to quickly recharge, I want to be able to from home if I need to.

Residential power in the US is 120 and 240 volts. You won't find a car on the market that can accept even 100 amps of 240 volts AC. Most Tesla top out at 48 amps max. and many other brands at less than that. 48 amps of current is all you need for one EV (requires a 60 amp circuit). And charging at a lower amperage than that does not protect the battery at all. It's probably slightly worse for it. You would need a power level that could replenish a pack from 0% to 100% in under 2 hours to even start thinking about battery degradation due to high charge currents.

Sure, if you will be charging more than one EV you might be able to put a 100 amp circuit to use with two wall connectors sharing the load. But you might consider running two 60 amp circuits as well. Most people will not need this much. Also, most people under-estimate how much capacity their electrical service has remaining under code. The total capacity in amps that can be installed in a 200 amp panel (for example) will be far above 200 amps worth, the exact amount depending upon the type of circuits installed (different circuit types have different assumed power factors). And different locals often calculate the maximum allowed somewhat differently.

 

[Crissa]

Also remember that AC chargers are big and bulky. They also get hot rectifying that current into DC and need cooling. The more you want to pull from the wall means more space and weight devoted to them on board.

This is really obvious with my Zero: They could double the capacity of the OBC in its current space, maybe triple - but then it would have trouble cooling itself.

In fact, in really hot places, the fact the OBC uses the battery case as its thermal mass can reduce fast charging from the Level 2 optional charger... Which itself is more than twice as bulky and needs active cooling (and costs $2500 and replaces the storage space).

To get AC charging at the same rate as a car, guys give over their panniers to chargers, too.

So somewhere in your truck there's a cubic foot of hardware devoted to charging just at 11kW (48a).

If you want to charge above that, it would be better to invest in DC charging point. Then the hardware isn't wasting space on your truck.

-Crissa

 

[tmeyer3]

The story is that a 14-50 can be installed behind a 40 or 50A breaker. Obviously you shouldn't plug anything that draws more than 40A into one that's behind a 40A breaker nor anything that draws more than 50 A into one that is wired behind a 50 A breaker. But you can only plug a 50A load into a 50A circuit if it is an "intermittent load" which is defined as any load which is connected for less than 3 hours unless that load is EVSE which is, by definition, not intermittent even if you plug it in for less than 10 minutes. Non intermittent loads require derating to 80%. Thus the biggest EVSE you can plug into a 50A wired outlet is 40 A and if it is wired for 40A the biggest you can plug in is 32 A. This explains the UMC's 32 amp rating. In an abundance of caution they have assumed that all 14-50R are wired to 40 A breakers and thus only allow the UMC to pull 32A from a 14-50. Other manufacturers EVSE with 14-50P plugs will allow the full 40 A.

Note that Tesla's corded charger which is hard wired with a 14-50P does allow the full 40A. Why this is I cannot explain.

The EVSE tells the car how much it can have. The corded connector is permanently to limit requests to 40A. The UMC is programmed by the other pins on the plug-in adapter. If you plug in the 14-50R adapter it programs the unit to allow no more than 32A. If you plug in the 120V 15A adapter it programs the unit to limit to 12A etc.

The HPWC is programmed through the WiFi interface. You can install an HPWC behind a 30A breaker and "commission" that HPWC for a 60A breaker in which case it will allow the car to ask for 48 A which will, of course, pop the 30A breaker.

I believe the new Ford will take up to 80A (requiring a 100A circuit). You can install multiple Tesla HPWC on that but you will have to go through a sub-panel with a separate 60A (or smaller) breaker for each.

Sure most of the time I will use a lower charge rate because I have a short commute and I want to protect the battery but that day that I need to quickly recharge, I want to be able to from home if I need to.

uh, ok. I really wasn't trying to make a "how to wire breakers" tutorial out of it.

 

[anionic1]

The story is that a 14-50 can be installed behind a 40 or 50A breaker. Obviously you shouldn't plug anything that draws more than 40A into one that's behind a 40A breaker nor anything that draws more than 50 A into one that is wired behind a 50 A breaker. But you can only plug a 50A load into a 50A circuit if it is an "intermittent load" which is defined as any load which is connected for less than 3 hours unless that load is EVSE which is, by definition, not intermittent even if you plug it in for less than 10 minutes. Non intermittent loads require derating to 80%. Thus the biggest EVSE you can plug into a 50A wired outlet is 40 A and if it is wired for 40A the biggest you can plug in is 32 A. This explains the UMC's 32 amp rating. In an abundance of caution they have assumed that all 14-50R are wired to 40 A breakers and thus only allow the UMC to pull 32A from a 14-50. Other manufacturers EVSE with 14-50P plugs will allow the full 40 A.

Note that Tesla's corded charger which is hard wired with a 14-50P does allow the full 40A. Why this is I cannot explain.

The EVSE tells the car how much it can have. The corded connector is permanently to limit requests to 40A. The UMC is programmed by the other pins on the plug-in adapter. If you plug in the 14-50R adapter it programs the unit to allow no more than 32A. If you plug in the 120V 15A adapter it programs the unit to limit to 12A etc.

The HPWC is programmed through the WiFi interface. You can install an HPWC behind a 30A breaker and "commission" that HPWC for a 60A breaker in which case it will allow the car to ask for 48 A which will, of course, pop the 30A breaker.

I believe the new Ford will take up to 80A (requiring a 100A circuit). You can install multiple Tesla HPWC on that but you will have to go through a sub-panel with a separate 60A (or smaller) breaker for each.

Correct I should have said a nema 14-60 would get you to 48 amps of charging capacity, which in my opinion is still light for the Cybertruck if you are doing a lot of traveling or ever need to charge quickly from your home in a pinch.

 

[ajdelange]

It's going to be inadequate for somebody at some time for sure. The question is how often it is inadequate, .001% of the time or 30% of the time. Should the percentage be high enough Tesla will do what they have done in the past: put more chargers in the truck. I see an easy path for this which I have mentioned here and elsewhere and that is to install a second complete charging port/charger in the truck. The current 10 kW charger will charge a 100 kWh battery at about .1C and the 200 kWh battery at 0.05C. Adding a second charger to the TM doesn't even stress the battery. Any TM owner with 2 HPWC (and many people do have 2 or more) located close enough to one another that the hoses will reach can then charge is TM at 1C. This should make life easier for TM owners for whom 0.05C doesn't cut it.

Pure speculation, of course.

 

[SpaceYooper]

Consider that the CT is a big heavy truck that is probably going to require half a kWh to go a mile.

AJ, what do you think the battery size is going to be? It seems like most speculations are 200 kWh. I don't remember seeing anyone speculate 250 kWhs or more. But it sounds like your saying it will be at least 250 kWhs to get that 500 mile rating and more then 250 kWhs to get whatever the 500+ means.

 

[ajdelange]

Starting with 500 miles range it's clear that the battery size depends on the Wh/mi. It's a big heavy truck though weight turns out not to be such a big driver. If it can run on 400 Wh/mi then the required discharge capacity is 400*500 = 200 kW. If it takes 450 that implies 225 and if it is as bad as 500 that implies 250 kW. So where does it actually fall? ABRP uses 485 for trip planning but that's at 65 mph which means somewhere around 450 for the EPA rating. The Rivian is roughly the same size and before they clammed up said they would be capable of 400 miles (also with the mysterious +) with an 180 kWh battery which gives 450 but note that ABRP predicts 516 for 65 mph cruise.

I cannot see a 250 kWh battery in the CT unless the new cells turn out to have appreciably more specific energy than the current ones (no pun intended) and at the same time I cannot see less than 400 Wh/mi which means I think the battery will be at least 200 kWh which leads me to my best guess of 220 - 225 kWh.

 

[Scott1911]

I am ready!!! (60A)

 

[Ogre]

As you say, everyone's needs are different, and I am curious where on the scale people feel their needs fit. I expect I am in the extreme minority feeling that I can get away with a 120v trickle charge. I'm not trying to convince anyone to side with me. Just looking to get a better understanding of whether the MORE POWER! folk are just a vocal minority or if a lot of people do expect to need a fairly high power setup.

Alot more people than you might think can get by on Level 1 charging. A Tesla can charge up to 1.8kW or ~6mi an hour on Level 1; it can also pull less if the outlet isn't a 20a.

If you're home 12 hours a day, that's 72 miles charged a day. Over a year, that's 26,000 miles!

I've been using 120v "Trickle" charge since I bought our Model Y in February.

We get roughly 4 miles/ hour, I suspect the CT will be more like 2-3 miles/ hour. On most days I get 50 miles. Often, that's enough but if I drive a bunch 2 days in a row, it can be trouble. Happens often enough that it's frustrating. I suspect with the Cybertruck it would be significantly more frustrating.

I don't think you need "MOAR POWER!!", but do feel like only being able to add ~30 miles range per night with the Cybertruck will be pretty limiting. Even 20 amps at 220v will get you close to 100 miles per night which is a lot more reasonable.

When we get our CT we'll be a 2 EV family. So I'm installing a wall charger on a 60 Amp circuit, enough to top off either the CT or my Model Y. I doubt we'll need 2 wall chargers though. If we do, the 60 Amps is enough headroom to fully charge both overnight using power sharing.

 

[ajdelange]

I did the calculation in #4. It's going to be about 2.4 (rated - more like 2.2 highway) mph for the CT under ideal conditions i.e. warm weather or garaged in a heated garage during winter. It surprises me that over 20% of respondents think, at this point, that this will suffice. It is even more surpising that 1 respondent is planning on fast DC charging but I suppose he is in a commercial setting.

 

[rodmacpherson]

I did the calculation in #4. It's going to be about 2.4 (rated - more like 2.2 highway) mph for the CT under ideal conditions i.e. warm weather or garaged in a heated garage during winter. It surprises me that over 20% of respondents think, at this point, that this will suffice. It is even more surpising that 1 respondent is planning on fast DC charging but I suppose he is in a commercial setting.

I think it depends on people's needs.
For me (we are a 2 EV... wel EV and PHEV that's used like an EV, house) I have been driving my commute on 120v charging for years and now with the new normal my commute is only a couple of times per week. ...and I have level 2 charging, sometimes for free at the office end, and a Supercharger a few km away from home if needed in a pinch. ... but being a 2 EV home I am equipping for a second L2 at home just for convenience.

With my 2012 Leaf (that only has about 50-60% of its original capacity) I can only get to work and home again once with a bit of spare charge each day, but it works. In Summer I charge to 80%, and in Winter I let it go all the way up to 100%

With a bigger pack I wouldn't have to get a charge equal to my commute each day. It could be less each day than what was used because it would have capacity to spare and can top back up on days it is not being used.

Back when I drove gas cars I didn't feel I had to fill it back up each night after a commute, I only dropped by the gas station to fill it up about once a week.

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