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Model 3 Charging Efficiency
- Thread starter insaneoctane
- Start date
I think @Dave EV and @insaneoctane are saying slight different things. @dave is is talking about vampire drain (susposed to be ~1%). I believe @Insane is talking about what I was thinking, not when the car is sitting locked, but when I am sitting in the car waiting, but not driving. I would imagine that accounts for a lot of drain that the car (probably) does not account for.
Garlan Garner
Banned
I thought the point of this thread was charging efficiency, not phantom drain or gaps between predicted and actual range, etc.
Can anybody provide more real-world details on what to expect in charging losses? Specifically, what percentage of power from the utility is lost during charging, and how much difference is there in this loss with various charging sources?
(Maybe I missed these details in all of the off-topic content in the thread.)
Can anybody provide more real-world details on what to expect in charging losses? Specifically, what percentage of power from the utility is lost during charging, and how much difference is there in this loss with various charging sources?
(Maybe I missed these details in all of the off-topic content in the thread.)
srs5694
Active Member
FWIW, TeslaFi is reporting a charging efficiency of 92.7% on my Model 3 when connected to the Clipper Creek HCS-40 I have at home, and about 90% on public charging ChargePoint stations. I suspect the difference is because my Clipper Creek unit is supplying 239V x 32A (so7.648kW), whereas the public stations I've used supply ~210V x 30A (so 6.3kW). I've only had my car for a week, though, and TeslaFi has only been active for a couple of days, so that's a very limited data set.
I'm using a Tesla Wall charger. I charge my 2019 Model 3 Dual Motor LR at 240V and 48A in my heated garage (52 degrees). That's a charging rate of 11.52kW per hour. I charged for 261 minutes, which is 50.112 kWh of energy consumed. My starting capacity was 26% and I charged up to 90%. Assuming my battery capacity is 74KWh, I added 47.360kWh to my battery. That's a charging efficiency of 94.5%. Make sense ? Am I missing something ?
AlanSubie4Life
Efficiency Obsessed Member
We can't tell because we don't know your battery capacity. You'd have to provide the number of added rated miles.
If that were your full battery capacity, that would be correct. But a 74kWh battery would have:
74kWh/245Wh/rmi = 302 rated miles at 100%. (And you added 193 rated miles.) What does yours show?
When you are charging in %, it should show you how many kWh were added to the battery, on the charging screen (with no decimal point), as long as the car is still plugged in. So in your case, it might have said 47kWh. Depends on your battery capacity.
But yes, your number is close to what is correct. Just keep in mind that on the trip meter, if you immediately went for a long drive, and went all the way down to 26%, using up that energy you just added, the trip meter would show about 230/245*47.4kWh = 44.5kWh used.
So referenced to trip meter numbers (which does not count energy used when in park, but that's a separate issue), your charging efficiency is 44.5/50.1 = 89%.
AlanSubie4Life
Efficiency Obsessed Member
Isn’t this just because you had heat or something running during the charging event, though?
Nope. Both motors wasting heat prior to charging. Got home, plugged in, and let it do it's thing.
Here's the previous charge (I used scheduled charging for a test). Outside temp plummeted to -18°C on the night of December 18th.
Start Date
2019/12/19 00:30:01
Duration
05:58:38
Charger Energy (kWh)
27.82
Charger Loss (kWh)
10.75
Start SOC (%)
62.31
End SOC (%)
85.51
38% charging loss (that one includes cabin heating, around 3kWh, bringing loss at ~28% )
So when it's that cold, I charge after my drive home.
Phil
Last edited:
AlanSubie4Life
Efficiency Obsessed Member
Sure. Definitely a good use of battery waste heat to charge when the battery is warm.
I just thought I'd share our findings on charging efficiency.
We have a model 3 that charges in our garage using the included mobile connector on a standard european 230V outlet.
That charges the car at about 18 km/h. We charge at home probably 98% of the time.
We never supercharged and only charged away from home on no more than 5 occasions.
We have a power consumption meter on the outlet we use, so we have a good idea on the actual consumption on that outlet.
We have 14,635 km on the car now, and that consumed 3529 kWh on the power consumption meter.
That's 241 Wh/km.
The car's trip computer shows an average consumption of 209 Wh/km over the complete lifetime (14,635 km).
So that would mean we have a charging efficiency of 86.72% (209/241).
It's probably even worse because we did charge away from home a couple of times. If we charged away from home for about 600km the charging efficiency is closer to 83.5%.
Part of the consumption losses can probably also be attributed to phantom drain when the car is parked but still consuming energy being connected to wifi or 4g. No idea how much that is though.
In any case, actual consumption of the car is probably closer to 250 Wh/km considering all of this, which is considerably more than the 209 Wh/km the car shows as lifetime average.
We have a model 3 that charges in our garage using the included mobile connector on a standard european 230V outlet.
That charges the car at about 18 km/h. We charge at home probably 98% of the time.
We never supercharged and only charged away from home on no more than 5 occasions.
We have a power consumption meter on the outlet we use, so we have a good idea on the actual consumption on that outlet.
We have 14,635 km on the car now, and that consumed 3529 kWh on the power consumption meter.
That's 241 Wh/km.
The car's trip computer shows an average consumption of 209 Wh/km over the complete lifetime (14,635 km).
So that would mean we have a charging efficiency of 86.72% (209/241).
It's probably even worse because we did charge away from home a couple of times. If we charged away from home for about 600km the charging efficiency is closer to 83.5%.
Part of the consumption losses can probably also be attributed to phantom drain when the car is parked but still consuming energy being connected to wifi or 4g. No idea how much that is though.
In any case, actual consumption of the car is probably closer to 250 Wh/km considering all of this, which is considerably more than the 209 Wh/km the car shows as lifetime average.
The lifetime average is probably only counting the energy consumed while in Drive. The phantom drain and climate control consumption while parked is not counted in the trip meter.
Well, since we're kicking an old thread here...
I know both of you may not be on the forum anymore, but what both of you are seeing is probably not mostly explained by charging efficiency. It's more probably the "1% loss per day" that Tesla claims. According to the Stats app for iOS, this is actually about 1.33kWh/day (median from their fleet), which is roughly 1.8% on an LR pack and 2.6% on the SR+ pack. It's almost equivalent to a 60W incandescent bulb constantly burning, powered by your car. This is nearly 500kWh/year, or the equivalent of putting on about 2000 miles.
For @Dbregmam specifically, you have a 80kWh discrepancy over just two months so far. Extrapolated to a year that would be 480kWh, which is indeed nearly 500kWh/year that would be the median standby usage for Model 3.
I know both of you may not be on the forum anymore, but what both of you are seeing is probably not mostly explained by charging efficiency. It's more probably the "1% loss per day" that Tesla claims. According to the Stats app for iOS, this is actually about 1.33kWh/day (median from their fleet), which is roughly 1.8% on an LR pack and 2.6% on the SR+ pack. It's almost equivalent to a 60W incandescent bulb constantly burning, powered by your car. This is nearly 500kWh/year, or the equivalent of putting on about 2000 miles.
For @Dbregmam specifically, you have a 80kWh discrepancy over just two months so far. Extrapolated to a year that would be 480kWh, which is indeed nearly 500kWh/year that would be the median standby usage for Model 3.
AlanSubie4Life
Efficiency Obsessed Member
The actual charging efficiency (in the US) using 7.7kW charging (not explicitly specified but likely use the charging equipment included with the car) is published by Tesla and available through the EPA iaspub website.
The charging efficiency at 240V/32A is about 88.5% on all the Model 3 variants (slightly higher efficiency for the SR due to lack of taper - so the true number might be closer to 89% if you're not charging to 100%). Obviously can be verified directly as well, if you're careful to pick an interval without vampire drain.
Your numbers are low because of vampire drain, and a low charging rate.
rejedejo
Member
Yep. "Drive miles" is what the Scan My Tesla app reading the CAN bus will tell you. The other kWh don't count, you know, lights, radio, wipers, heat etc.
rejedejo
Member
I have a kWh meter in between my charger and wall outlet and have been taking data for a couple years. It's variable. I think there's a lot of stuff going on in the car that uses power that isn't logged visibly to typical consumers. there's significant rounding error as a kWh is pretty large quantity of energy but the charging efficiency as the difference between what I measure and what the car logs as AC Charge (per Scan My Tesla) varies from as high as .94 to as low as .71. The issue really is that we shouldn't have to guess this number, or have back door methods to measure, it should be part of the car, a true and accurate input kWh meter, reported the same as miles are. Tesla won't do this without being required because their numbers wouldn't look nearly as good.
rejedejo
Member
The odometer reading in your Tesla reports 'Drive kWh' none of the other stuff is counted like radio, lights, heater, AC etc.
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