Usable KW Doesn't match up??

[zentage]

I drive 120-130 KM/hr, But I am also in Vancouver, Canada... So very mountainous terrain.

at 120-130km/h speeds a tesla will use alot of energy, not much you can do about it except drive slower There's quite a big difference if you go below 100km/h

 

[wdolson]

On most highways in the western US, you will have traffic streaming past you and you might even get a ticket for holding up traffic if you're doing less than 130 Km/h. At 100 Km/h semis will often be passing you.

I haven't driven the open highways in Canada, most of my trips to Canada have been to Victoria which is on an island and the only times I've been to the mainland was in Vancouver which is big city driving only. I expect the major rural highways of Canada are normally 120-130 KM/h too.

 

[cwerdna]

Limited to 72.6 KW? Temperature (K = Kelvin) times power (W = Wattage)

Or

72.6 kW = 97.4 hp? That is indeed a slow accelerating car.

Or

72.6 kWh denotes value of energy capacity

Keep your units on track when discussing technical properties

Yes. OP needs to get their units straight.

kW and kWh are very different metrics. It's the same as confusing gallons with horsepower. Think of kW = horsepower, kWh = gallons.

If one charges at 1 kW (or 1000 watts) for 6 hours, 6 kWh came out of the wall. If it's at 6 kW for 1 hour, it's also 6 kWh. If it's 1 watt for 6000 hours, it's also 6 kWh.

One pays for electricity at home in cents per kWh. In the US, there are a few utilities w/residential plans where they not only bill per kWh but also have demand charges, but that's rare and complicates calculations. (Demand charges aren't unusual on many commercial plans.)

(BTW, 1 hp = ~0.746 kW. And, many .gov sites say 1 gallon of gasoline=33.7 kWh.)

 

[wdolson]

It would probably be easier if the common usage was Joules instead of KWh. People would probably like having a P360000D (3600 Joules = 1 KWh).

 

[DB 2]

So i recently did a little test with my Model S 75D. I charged to 100%, and ran the battery down almost to zero miles left to see what the usable Kw were (just approximate). What I found (fig.) is that the number was not even close to what people have reported as the usable KW for a model 75 Battery (72.6 I believe). Can anyone explain this difference? At 10KM left,
since the last charge the used KW is 59.6. Seems like about 12KW of usable power have vanished. (BTW this test was done over less than 24 hours, so shouldn't be that much "vampire drain").

Try running the test again when you have a long trip and can do all the consumption in the shortest possible time. Having a shortage of 5 or 6 kWh seems reasonable, but 12 kWh is way too much. BTW, what is your rated KM at 100% state of charge?

 

[Rafaelm]

Can I be the crazy one here and say that Pre AP2 being enabled in shadow mode, the math was a LOT closer ?

 

[wdolson]

I suspect vampire loss while the car is parked is not counted in the WH used. I saw a drop of 2 miles of range parked for a little over 90 minutes. When I arrived at my appointment, the miles used and remaining miles added together matched my rated range when I left. I forgot to record the WH and WH/Mi when I got back into the car (I got on the phone and the phone displays replaces the trip odometers). When I got off the phone the WH/Mi was about the same as when I got to my appointment, but the range remaining plus the miles driven added up to about 2-3 miles less than when I started.