plugged in at work first time @ 120V hum-dee-dum

It's -20C today in Canada where I live, and this is when ICE people plug in their block heaters. So I didn't feel too self conscious about using my charge port at work for the first time. All they currently have is 120V outlets... for block heaters. I'm working on getting charger stations put in... next year.

Anyway, at the app-reported charge rate of 6 km/h, the math says it will take my full 8 hour work day to get back to the same state of charge as when I left home this a.m. So that's fair.

Of course, my main reason for plugging in was to have stress free use of interior climate warming feature before heading out... not feeling bad about subtracting useful range in doing so. Or will the mobile charger at 120V12A have enough jam to do both? Maybe not enough to maintain at least some charging rate AND do climate control warming when it's -20C outside. I'm about to find out later in the day...

Also, I imagine keeping a "trickle charge" on all day is a means of keeping the battery pack warmed, hopefully avoiding the dreaded "regen has been disabled" warning I get when having parked outside in the negative temperatures for hours. We'll see. Report to follow.

update

About 1.75 hours into this... the car is reporting a gain of 10 km range. Pretty much getting that reported 6 km/h rate put into the battery.

Ambient temps have risen a couple degrees... maybe -18C where the car is sitting.

Interior temps had dropped from my comfortable cruising choice of +20C to +4.5 in this parked time.

Experiment time. I decided to give it a shot of interior warming. Within a few minutes it had gained interior heat and reported +5C interior.
While I was doing that I watched the charge rate. It didn't waiver from "6 km/h" BUT the estimated time to charge began inching up as interior heating was going on.
I bet the estimated time to charge just would have kept going up unbounded if I left climate on. A slippery slope of going nowhere.

Obviously needing to use battery power to heat the interior, to deliver the needed power to climate system.
Which was more than the mobile charger could deliver, because charge to complete time reversed direction and kept going.

I shut the experiment down.

So that's confirmed, this circuit cannot provide enough to do both heat and charge.
It provides "charge" OR "supplement interior heater", not both.

I will save the climate heating to end of day when I need it the most.

I will check mid-day with a drive to see if the regen and top end limiters are showing due to cold battery.
I have 340km range roughly at the moment so top end won't be limiting because of low batt, only if battery is cold.

I had the same thought about NEMA 5-20 and will look for the tilted pin on the receptacle at lunch.
I tried dialing up past 12A on the dash... nope, limited by the adapter mated to the mobile charger.
It's probably worth getting the next adapter up for NEMA 5-20 if the receptacle allows...
(or just change the resistor in the 5-15 adapter I've already got, and put a switch on it to select the resistor.
And/or I can always dial down the amps drawn from the dash if I forget to flick the switch. Shh!)


re: battery surface area. Yes, it's cold here, and it's a huge surface area. (Don't know how snuggly that titanium plate keeps the battery...) but the battery is also a huge mass. So I'm counting on thermal mass to help beat the surface area war. Is there a thermodynamicist in the crowd who can chime in? When it's blowing snow AND -40C here... that will be a different story.. maybe tempted to make an inflatable bladder wind blocker / air dam that seals all around the perimeter of the car to the road, or at least, the side facing the wind

I'm the only one on the breaker today, nobody else in my row plugged.

Mid day udpate:

Ambient is now about -16C.

I haven't done my lunch run yet, to check power restriction limiters.

Here's what I do see.

Avg charge rate is still reporting 6 km/hr.

I'm up 26 km range since start, 5 hours ago. So I'm really only taking on 5.2 km/hr. But I did do that experiment with interior climate for a few minutes.

Here's what else, the estimated time remaining to reach set charge limit is reading 4.75 hours still to go (charge set to 90% which is about 385km for my car).

Hm.. This a.m. it was projecting about 8 hours to reach goal. 5 hours have passed. And 5 remaining.
Tells me if it really is achieving 5.2 km/hr throughout, then that's closer to the truth and would occupy the 10 hours.

Call that optimistic rounding on Tesla's part. 5.2 rounded equals 6.
Or, some juice is leaving the battery at 0.8 km/hr just sitting there.
I figure battery heater hasn't had to come on otherwise we wouldn't see these gains that have reached the battery... based on that climate draw experience...

Anyway, the dynamics of this experiment are about to change because I'm heading out for a hit. I mean drive.
I want to see if the high or low limiters have appeared, or if the trickle charging has kept those demons away.

By the way, interior is reading 0C, because it's sunny.

I'm in Edmonton. Dude, where you from? If you are a west coaster... Vancouver you have no excuses to avoid model S due to temperature related concerns, if I can make one work where I live!

Turns out I didnt drive mid day, got too busy.

So it managed to reach "charge complete" by 4:15 maybe a little sooner but thats when I looked, and saw 381 km range.
At home I typically get 385 to 387 where the slider is set. Must be the hi octane electrons of 240v 80A circuit there.

Hopping in the car my dreams were dashed, limiter bars showing top and bottom of scales reduced. But at least my regen wasnt totally disabled.. which I am pretty sure it would have been in these temps if it wasnt trickle charging all day.

BOTTOM LINE I drove home for free. So yes 120v charge was worth it. If I do this every day, my fuel bill drops in half. Maybe $20 a month instead of $40, ha!

If youre driving in from that way on hwy16 stop by with your future S and charge up, ive put my HPWC on plugshare.

ljwobker said:

I'm pretty sure that the "charge rate" reported is the current and voltage going through the charger - NOT the net power being sent to the battery. So regardless of what else is going on with the car's systems, you're going to be putting (in your case) 12A @ 120V =1.4KW through the charger. That juice all flows into the battery, but other systems such as the HVAC, battery heater, etc are drawing on the battery at the same time.

So... the moral of the story (again, I think with relatively high confidence) that you can see a "charging rate" that is positive and only a function of the input AC power source... while the "time to charge" reflects the NET power going into the battery.

Maybe someone else can confirm or deny this...

Click to expand...

I concur

- - - Updated - - -

m1ker said:

scottm, I think I'm going to do the same with our HPWC, once it's installed in our garage (make it available via plugshare). So if you find yourself in The South end of Calgary needing a charge, just call. For now we have a J1772 30A 240V plug available. Our model S should be here in early March or hopefully sooner.

Click to expand...

mighty kind o' ya pardner, may just take you up on that... Cowtown is perdy scarce on ev chargin' stations in the south, and that's where my ma lives.

nuff of that speak.. hehe

Did you catch the news of Superchargers installing in Canmore right now?
And Red Deer is queued up to get one at some hotel...
Getting better all the time!

What are you charging right now with the 1772?