Ideal amps for charging long range model 3 at home

[jbcarioca]

Nobody seems to be realizing just how flexible the requirements are if your car will consistently charge overnight. That is, except @A2be and @ngogas . I have happily existed for almost five years with a 208/30:connection that typically delivers 199/23 due to other loads on the same board. When I first bought my S I was very worried that this would be unacceptable.

Realistically I always can obtain a 100% charge if I really need to have one. Five years ago that did happen because Superchargers were scarce. Now I almost never charge above 80% because a stop at a Supercharge location is usually a biochemical necessity anyway. Further I very rarely have an overnight stay without a Destination Charger and when I do there are almost always other charging solutions available.

That is simply to say that it is a very rare EV owner who really needs much more than 208/30, and that only because @ngogas is quite right that living with only 110v is not very practical. ~24 hours for a full charge is tiresome, even longer if you have cold weather.

 

[jcal0820]

Anyone have a photo of a 6-50 (240v) outlet? This might be the one in a relative's garage.

 

[Rocky_H]

Anyone have a photo of a 6-50 (240v) outlet? This might be the one in a relative's garage.

There's a little table on this page showing some of the common ones, including 6-50.
NEMA connector - Wikipedia

 

[jcal0820]

Got the 14-50 I installed today w a 240 oulet, on a 50A breaker, & using the stock mobile charger with the 240v adapter. Already seeing MUCH greater charging speeds from the old 120v outlet, as posted here...

 

[AlanSubie4Life]

Got the 14-50 I installed today w a 240 oulet, on a 50A breaker, & using the stock mobile charger with the 240v adapter. Already seeing MUCH greater charging speeds from the old 120v outlet, as posted here...View attachment 466822

Sounds like you've come from 120V charging....so you've also seen a big step up in efficiency for your LR RWD Model 3 (though a little bit more loss in your wiring, it's just a couple % or so probably). (Can deduce from your miles per hour and known typical efficiencies that you must have a LR RWD Model 3...right? I hope... )

235V*32A/234Wh/rmi*0.92 = 29.55 rmi/hr

235V*32A/234Wh/rmi*0.95 = 30.5 rmi/hr

So efficiency is between ~92% and ~95%, depending on how the actual number of miles per hour was rounded.

Before, you were probably closer to only 75% efficient!

 

[SleeperService]

Only slightly OT, but @AlanSubie4Life, I just noticed in your signature that you are getting exactly the same lifetime [1 year] Wh/mi that I am. I'm a bit surprised by that given that I'm in the midwest, which has a little something called "winter" and you are in San Diego. I guess the aero wheels I've got could be just enough to make up for that deficit? Anyway, thought that was interesting.

On topic: in your equation above, for our cars [P3D] the calculation is 250 Wh/rmi, correct?

 

[AlanSubie4Life]

Only slightly OT, but @AlanSubie4Life, I just noticed in your signature that you are getting exactly the same lifetime [1 year] Wh/mi that I am. I'm a bit surprised by that given that I'm in the midwest, which has a little something called "winter" and you are in San Diego. I guess the aero wheels I've got could be just enough to make up for that deficit? Anyway, thought that was interesting.

On topic: in your equation above, for our cars [P3D] the calculation is 250 Wh/rmi, correct?

I have a P3D+. The lack of aero wheels and the somewhat wider and stickier tires make a big difference. I expect I'd be at closer to 240-250Wh/mi lifetime if I could use the MXM4s plus aeros. Also pretty hilly in San Diego and that hurts a bit just due to energy slosh. Aeros are a little side project I haven't gotten to yet. I had improved to 280Wh/mi lifetime, but now I'm closer to 282Wh/mi lifetime after my 1200-mile ~290Wh/mi road trip (where I used CrossClimate+ tires + Dekagrams which aren't significantly better efficiency than 20s plus PS4S, at freeway speeds, as it turns out).

For our cars (and all Model 3 AWDs), the calculation uses 245Wh/rmi (for charging) and 230Wh/rmi (for the trip meter).

 

[SleeperService]

I have a P3D+. The aero wheels and the somewhat wider and stickier tires make a big difference. I expect I'd be at closer to 240-250Wh/mi lifetime if I could use the MXM4s plus aeros. Also pretty hilly in San Diego and that hurts a bit just due to energy slosh. Aeros are a little side project I haven't gotten to yet. I'm closer to 282Wh/mi lifetime after my 1200-mile ~290Wh/mi road trip.

For our cars (and all Model 3 AWDs), the calculation uses 245Wh/rmi (for charging) and 230Wh/rmi (for the trip meter).

Are you sure on the trip meter? On my car at least, if my efficiency average (on the 5-15-30 mile graph) is better than 250 Wh/mi, it's below the "rated" line on the graph. I'm pretty sure the "rated" line is at 250 Wh/mi is what I'm saying, I guess.

I managed 262 Wh/mi average over the "warm" months from April to the end of September [~14k miles]...it's starting to creep back up now...

 

[electracity]

"Ideal" for the LR model 3 is the tesla wall connector on a 60 amp circuit. That's what I did, but it was probably completely unnecessary for a garage where you expect to have only one charger. Well, perhaps not "completely unnecessary". If I had a very long commute I might feel good about maxing out the charging rate.

The best reason to put in a bigger circuit is anticipating the future with multiple EVs. That is where the wall connector shines. I have a detached garage and installed a 100 amp subpanel.

Anyone installing a new circuit to a garage from a remote panel should consider wire to support future EVs.

 

[AlanSubie4Life]

Are you sure on the trip meter? On my car at least, if my efficiency average (on the 5-15-30 mile graph) is better than 250 Wh/mi, it's below the "rated" line on the graph. I'm pretty sure the "rated" line is at 250 Wh/mi is what I'm saying, I guess.

Positive. You can check out my trip report data in the Driving Dynamics forum. Was an opportunity for me to test this on some very long trip segments with widely varying efficiency at a steady state battery temperature.

Regarding the Energy Consumption graph, it's a little confusing. The line is at 245Wh/mi in my car. If you take the efficiency number you have achieved for your last 5/15/30 miles (on the left hand side), then take your battery gauge miles, and use this formula: battery rated miles * 245Wh/rmi / (efficiency over 5/15/30), you will end up with the projected range number it displays on the right of the graph (of course with some small 1-mile rounding error sometimes).

On the other hand, for the trip meter, for reasons not well understood, if you note before rated miles, after rated miles, and then look at the trip meter for a decent length trip, and do the calculation:

Initial rated miles - (Trip Meter Avg Wh/mi) * (Trip Meter Distance Traveled) / (230Wh/rmi)

You will find it matches your final rated miles. (With caveats regarding battery temperature changing significantly, ending on a downhill, etc.)

Yes, these two pieces of information are contradictory. (The projected range on the Consumption graph is a bit optimistic, since the rated miles click down faster, by the ratio of 245/230, than it predicts. The consumption over the chosen window DOES match the trip meter, so it's not like the scaling of the entire thing is just different...it is just...off)

If you find that the location of your line is different or one or both of the formulas don't work, do let me know. That would be curious. I've been under the impression that all AWDs are the same, based on one other example I have looked at, but I could be wrong; can only speak for sure about my car TBH.

 

[MaryAnning3]

my 2 cents: charge speed at home is rarely an issue since you are there overnight. 20 amps, 32, 50 amps all work fine. They key advantage of the Wall Mounted Connector from Tesla is the convenience and that you can leave the mobile connectors in your car where you may use them now and then.

 

[MaryAnning3]

Also, for anyone new, I recommend displaying your state of charge in percentage (not miles).

 

[AlanSubie4Life]

is better than 250 Wh/mi, it's below the "rated" line on the graph. I'm pretty sure the "rated" line is at 250 Wh/mi is what I'm saying, I guess.

You are correct about this. It is at 250Wh/mi.

The line is at 245Wh/mi in my car.

This is wrong, however, the calculations on that graph are based on a 245Wh/mi constant. (You can easily check this with the three numbers available - battery miles, current efficiency, and projected range. ). So what I am saying is that the line should be at 245Wh/mi for the displayed numbers to make any sense.

related from yesterday:

Picture of P3D Energy screen

This is off-topic though, so can probably discuss in another thread if it is ambiguous.

 

[SleeperService]

@AlanSubie4Life Cool, that makes sense. You were making me think I was either insane or my car was different because it sure LOOKED like that line was at 250 Wh/mi. I believe you and understand what you are saying on the calculations though.

 

[jcal0820]

Also, for anyone new, I recommend displaying your state of charge in percentage (not miles).

..what’s the main advantage for this?

 

[Rocky_H]

Also, for anyone new, I recommend displaying your state of charge in percentage (not miles).

..what’s the main advantage for this?

There is no "advantage"; it's a preference. There have been gigantic threads discussing this preference. Here is a 14 page thread with a poll that was split almost evenly between the two. Go ahead and read through that if you want to get some idea of it.
Percentage or Miles/Kilometers : which do you use and why?

But the reason she is recommending that to new people is for two main reasons:

1. Rated miles has more granularity, since it's around two and a half to three rated miles in each percent. So people may see their full charge level shift from 310 to 309 and then come on the forums in a panic, thinking their battery is dying and trying to book a service appointment. I am not exaggerating. I saw the thread of someone freaking out and doing that over 1 rated mile of difference. Percent is bigger, so people probably wouldn't see the number shift much, so might not notice or think much about it. So it's kind of an "ignorance is bliss" thing.

2. Some people are just very uptight and get continually annoyed that the term for that number says "rated miles", but it does not match their real distance driving miles in all conditions: 40 mph, 90 mph, winter, summer, uphill, downhill, whatever. And they get really angry about that and don't want to see it because they feel it is "misleading". If you have a more calm and laid back personality, though, you can be OK with knowing that the rated miles usually just run ballpark a little bit high, so you can glance at it and say, "Hmm, 186 rated miles? Yeah, I can probably do 150ish with that." We think of places we drive in terms of distances, not in %, so having a rough slightly high number of rated miles is at least a little bit informative, whereas people don't think in terms of how many % it is to grandma's house.

So there you go; that's the difference. @MaryAnning3 was trying to head off some of that nervous anxiety that a lot of new owners get when they are scrutinizing every little thing in their first electric car and often freak out about how they see those factors with rated miles. But for a lot of long time owners who are comfortable and relaxed with knowing that rated miles aren't supposed to be a carved in stone measurement of exact distance in all conditions, it's a little nicer and more informative than %.

 

[MaryAnning3]

..what’s the main advantage for this?

Also, it helps you take care of your battery. You know where 20% and 80% are without doing a calculation. I also think it is more accurate because percent is a simple function of voltage for 21700 cell chemistry.

 

[Bblsttx]

I wrote this guide up to answer basically this exact question:

How Should I Charge My Tesla? – Article625.com

Ordered my LR AWD on Nov 1st. Super excited!

Thank you for putting this article together, extremely helpful in explaining the various options in a simple to understand format.

 

[tbwnm]

Forgive me if this is already answered in this thread (I scanned through but couldn't see the answer), I have a 2019 M3 SR+ which I understand can only draw a maximum of 32 Amps from the Tesla Wall Charger on a 240V circuit whereas the LR can draw up to 48 Amps (unless this changed recently through a software update?). Therefore, for my situation I would only need a 40 Amp circuit breaker? Have received estimates from 3 electricians for the install and one of them quoted a 2P 60 Amp breaker which I'm thinking is overkill for the Model 3 SR+ and would be pushing it on my panel which is only 100 Amps. Have looked at power requirements overall for my home with the electrician and either way it should be able to handle the load. The main competing draw will be the 5 ton AC condenser but that won't be running during times when the car is charging (only have the one 5 ton unit). If the circuit trips I'll have to go down the road of upgrading to a 200 amp panel (may also need to request more power from the utility provider). That will probably add another $1,500 to 2,000 to the install which I would like to avoid if possible.

 

[Rocky_H]

Forgive me if this is already answered in this thread (I scanned through but couldn't see the answer), I have a 2019 M3 SR+ which I understand can only draw a maximum of 32 Amps from the Tesla Wall Charger on a 240V circuit whereas the LR can draw up to 48 Amps (unless this changed recently through a software update?). Therefore, for my situation I would only need a 40 Amp circuit breaker?

Yes, that is exactly correct. The SR, SR+ and the short lived medium range all have only a 32A onboard charger, so that is all the current they can take. So that is correct that a 40A circuit is the proper level to provide 32A continuous. There's nothing that would be wrong with going higher, but your car just couldn't make use of any more than that.

Have received estimates from 3 electricians for the install and one of them quoted a 2P 60 Amp breaker which I'm thinking is overkill for the Model 3 SR+ and would be pushing it on my panel which is only 100 Amps.

That's just electricians not knowing the difference and playing the statistics. Most Model 3 buyers are getting the long range, probably, so most of the requests they are getting are for 60A circuits, so that's what they thought you would be wanting too.

You could go higher if you are trying to future proof, to prepare for splitting the power between two Teslas or things like that, but for your current car, a 40A circuit is the max you can use.

It is allowed to put a 14-50 or 6-50 outlet on a 40A circuit, so you could do that and just use the mobile charge cable that plugs into it, or you could put a wall connector on it and set the internal dial for a 40A circuit level. Either works.