How Many kWh in a Full Charge?

The charge won't disappear once it's in the battery so, yes, you can probably increase your usable cold-weather EV range a bit by charging in a warmer environment. Note, however, that what matters is the temperature of the battery pack and not the ambiant air temperature. It may take several hours for the pack to warm up after an extended cold period (such as being parked overnight in a cold location).

 

My EV actual today was 11.0 miles and it's 23 degrees here. I have my car parked outside with no shelter from the cold. 11 miles EV is not bad, considering how cold it is.

 

As recently as mid-December I was getting 48-51 miles of range commuting in my Volt at 55-57 mph but I'm now down to 41-42 miles. Overnight charging temperatures are mid-40's and my morning commute is around 35-40F for 46 miles. I'm now using 0.1 gallons of gas to make it into my workplace parking lot.

 

today was 17 degrees. i saw a much sharper drop in range going from temps in the 70's down to the 50's and 60's than i have anything colder .

 

I have a feeling that your strategy of charging just before departure is really helping you in these lower temperatures.

 

with or without cabin heating ? the cabin heater can draw 5KW. I found a huge range benefit by heating the cabin while still plugged in.

I use this script to do it from my desktop.
Script to start the Volt

 

John, electricity used for preheating should be counted toward your EV miles (if not already).

I heard it does little in 20 mins. How does it makes a huge difference for you? How many mins do you preheat?

 

I try to pre-condition a few minutes before departure, if I am plugged in. It turns off after 10 minutes if I don't start the car. I find that the car can be nice and toasty in about 3-5 minutes. I verified that the electricity does get counted in my kWh stats.

I have been driving my daughter's Prius this last week while my son has the Volt. It takes the Prius about 4 miles before the cabin gets heated ...

 

Almost entirely without cabin heating and I don't bother to pre-heat either. I recently started wearing a light jacket while driving in the early morning in addition to an undershirt and long sleave shirt. I don't even bother with the heated seats. I don't wear gloves or thermal underwear. Obviously, results may vary in colder regions. Minimizing the "wind chill" of air flow from the vents towards the driver makes a big difference.

I keep the air on non-recirculate (auto) and directed towards the floor and windshield. I set the fan speed to the lowest speed necessary to keep the windshield from fogging up excessively. Until recently I kept the fan off entirely but with colder temperatures I'm now using the lowest speed with an occasional short burst of the 2nd lowest speed setting.

The other day when it got down to 35F I gave in and ran the electric heater on "eco" mode for around a minute or two to clear up some persistent fogging that developed after driving for 40-50 minutes. After that it was back to "fan only" until I got to work. Driving home after work is even easier since it is warmer.

This is my daily commute drive. I'm not working hard at it. I just set the climate controls before leaving the garage, drive out to the highway, and put it on cruise control while listening to podcasts. Easy.

 

The preheating in the Volt can either come on in "eco" or "comfort" mode depending on the state of the climate control settings when the car was last driven. The "eco" mode restricts the heater's power consumption and is much slower to heat up a cold vehicle.

The behavior of preheating should really have a separate configuration setting and not rely on the climate settings used while driving. This is a source of confusion and is awkward. Fortunately, I don't feel the need to use it frequently in my climate region. I tend to only use it when I am driving guests to and from dining etc. on cold evenings.

 

If you prehead 20mins before you leave it actually heats up and then has time to cool off. (There is a lot of thermal mass, so while the air is warm when blowing, as soon as the 10min preheat cycle stops, the car can cool down pretty quickly). If you only have 120v (as I do) it takes another 10min (20min total) to recover a full charge as the heating can take more power than the 120v can supply. I rarely preheat because of that.

Since I normally walk between my two offices (about a mile), I wear a jacket, hat and gloves, anyhow so even at 0F, I rarely use anything more than a seat heater.

 

Are you sure about this? My PiP switches from EV to HV mode at 23.1%. 18% is the lowest SOC I've seen with 2 HV battery bars showing.

 

Re: charging losses, if you're curious about the values for the Leaf, see My Nissan Leaf Forum • View topic - IS THIS NORMAL FOR A LEAF?. Ingineer is pEEf here and he's behind evseupgrade.com + a bunch of other projects.

 

that thread assumes a 200-400 watt fixed overhead on the leaf, regardless if it is L1 or L2 charging. 200-400 is quite a large range when you consider the PiP's L1 charging is something like 1,400 watts. Perhaps someone can narrow it down for the PiP.

I don't think I have used 120V since August. On 240V, depending on just how low the temperature is, it seems I can do a pre-condition with the remote start and not dip into the battery. I assume this means the pre-conditioning is drawing less than 3.3KW from the plug. If it's colder it seems to dip into the battery initially but recovers within the 10 minute window, probably drawing 5KW (plug + battery) initially and then less than 3.3KW after warming the cabin. I should watch the ChargePoint graph and capture a screen next time. I really wish the Volt would draw 6.6KW from the plug. Perhaps I should be more conserving, but my EV subscription is 14 cents per day, with or without pre-conditioning.

 

Outside temps definitely impact how much heat is needed, and how much it does. Well weather in austin is a tad warmer. It was 7F yesterday when I left, it was also quite windy and 20F in my attached garage (the other reason I don't precondition.. since I've not hacked the ERDTLT).

There are threads on gm-volt that show pre-condition and recover
TED 500 graph of two 10 min precond on 110v & 220v

 

Well, it was only 3-4F warmer this morning (38F at my destination) and I got 43.9 miles of range in my 2011. A 2013 Volt, which has an extra 3 miles of EPA battery range, would probably have gotten 47-48 miles today.

 

Have you kept track of the matching kWh consumed from the battery that was indicated from the display in the car. A running cumulative total across all of those recharges would be best so as to average out the small errors and truncations that would occur if you reset the counter for each individual trip. That would let us compare the total indicated battery power vs. your measured "wall" charge kWh. Do you blend your EV usage with the gas engine or do you use up all your EV before the car switches to gas. Doing the later might minimize any inadvertent "charge stacking" of regen energy that actually came from running the gas engine.

 

The car automatically switches out of EV mode to HV mode when SOC hits 23.1%. SOC can continue to drop in HV mode. The lowest I've seen it was 18% with two battery bar segments visible. 23.1% has 6 battery bar segments visible. EV mode will not be available again until SOC rises to 27.9%, and it will automatically switch back to EV mode when it rises to 32.9%.

If you've depleted EV mode and are running in HV mode, the car seems to prefer to stay around 22% to 23% SOC (6 battery bar segments). I've rarely seen it drop below that, whereas in my Gen II, it would be all over the place.

What is interesting about your table is that it shows that 240V charging is clearly more efficient when charging from the same SOC starting point. There's a 300Wh difference in power consumed. Or about 11% or so.