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mknox
Well-Known Member
Weird. I always get 12/12 or 16/16 at 120 volts, and all of my other adapters give me the full rated amount too. In my case, it is just with the odd 80 amp J1772 station in combination with my J1772 adapter that will give me 79/79 for some reason. Tesla even loaned me a couple of J1772 adapters to try, but they all gave me 79/79 at the suspect station that worked fine at 80/80 for other Model S's.
Where are you measuring amperage? What is your software version?
I tested a Model X I got as a loaner, it had the same exact behavior. Service center couldn't repro.
Me: "Did you use an actual meter?"
Tesla: "No we just looked at the car and it said 12/16/etc."
Me: "Duh I said that's the part that's wrong"
mknox
Well-Known Member
My Model S is running 8.0 (2.46.16) and I was referring to what the car is displaying.
About 2 years ago, I had it plugged into a Kill-o-Watt type of meter at a friend's place so I could show him how many kWhrs the car was using, and it was showing 12 amps when the car was showing 12 amps. I only did that once.
I have a TED energy meter at home, and my car and the TED do match there when I'm charging at 240 volts. (I have to do some math to calculate Amps because the TED shows kW and Volts).
The display is now WRONG. Spent like an hour putting this data together, hopefully it makes sense. You can even see my second charger kicking in at 41 A.
whttiger25
Member
So, if you use a NEMA 5-20 plug plus a third party 5-15 adapter and plug into a standard circuit, and set the amps in the car to 12, will it actually be 12?
whttiger25
Member
Are you ever tempted to set it to 13A, or 14 even? I know you aren't supposed to draw more than 80% but I happen to know the plug I use has nothing else on it, ever. I charge at work on a plug in the garage and barely get my commute mileage each day, and pay exorbitant rates to charge at my condo. If I could add 10-20% to my daily charge at work it would be great.
No. Fire hazard plus the breaker will probably trip, leaving me with 0A.
If Tesla will fix this bug they introduced, you'll get 10% back on your "12A" charging already.
mknox
Well-Known Member
That would violate the rule of 80% of the circuit's capacity for continuous loads. If you try it, the breaker may end up popping after some time as it gradually heats up.
mknox
Well-Known Member
Interesting. As I say, the last time I actually metered it on 120 volts was probably 2 years ago (when it was consistently 12v on the meter and in the car). That was obviously many firmware versions ago. I pulled out my Kill-o-Watt and found the LCD display is shot (even tried new button cell batteries in it), so have no way right now to test myself.
Although, I do have one of these and could plug into my 14-50 and meter it on my TED....
whttiger25
Member
I can confirm my vehicle exhibits the same behavior. I am using a 5-20 plug now with a 5-20 to 5-15 adapter, setting the charge rate in the car to 12A, and getting my full charge.
I did use a killowatt to test, but if you don't have one you can confirm by sitting inside your vehicle with less than 24 hours of charge time indicated at 11A. Set to 10A and see roughly how much the time increases. Set back to 11A to see charge time return to what you started at. Then if you set it to 12A, you will see the charge time remains constant rather than decreasing further. This test works best once you have been sitting in the car for a few mins with climate control off (so that most of the energy from the plug is actually going to the battery and the computer has already adjusted for the net charging energy accounting for what's diverted to electrical systems and screen)
I did use a killowatt to test, but if you don't have one you can confirm by sitting inside your vehicle with less than 24 hours of charge time indicated at 11A. Set to 10A and see roughly how much the time increases. Set back to 11A to see charge time return to what you started at. Then if you set it to 12A, you will see the charge time remains constant rather than decreasing further. This test works best once you have been sitting in the car for a few mins with climate control off (so that most of the energy from the plug is actually going to the battery and the computer has already adjusted for the net charging energy accounting for what's diverted to electrical systems and screen)
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I just tried this again after first trying it when I first bought the car back in March of last year. 11.01 amps @ 122.1 volts on my Kill-O-Watt. It displayed 12/12 amps. So yea, somewhere along the way the current dropped. This was plugged directly into the wall without an extension cord.
whttiger25
Member
It's clearly a bug, and it affects people like me. I charge at work at 120V, every single day, and get pretty much exactly my commute mileage. This 1 amp over the course of my day, every day, adds up. Just seems like a simple bug to fix yet it has not been...
Making someone's charging between 7 and 11% slower on the most common outlets in North America sucks, and that could be significantly worse if the pack heater needs to turn on. Sometimes there is no choice. I'm going on a ski trip this year and the only option is 110. I didn't book the lodging so it's either don't take the Tesla (and show everybody how impractical EV's are), or try and get enough juice on 110.
Do you have the 5-20 adapter? Most 120V outlets at commercial properties are 20A. Charging with that adapter at 16A (or even 15A) is significantly better than charging at 12A, whether it's really 12 or 11.
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