Range question to forum

[brunoylupe]

I thank all participants for an excellent forum!

I ask if anyone can provide me guidance on the likelihood that I may, or may not, be able climb 4000 feet in a Spark. 25 miles relatively flat to gentle uphill and then another 25 climbing...up,down,up,down,up,up,down,up,up,up to 4000 feet.

Charging while at work will be possible, I think...I hope...
I may need an extension cord...can I also read why that is discouraged?

And back down after 8 to 10 hours.



I want a Spark; but, i am still trying to figure some things out.

bgs

 

[StevesWeb]

I may need an extension cord...can I also read why that is discouraged?

End users may select an extension cord with insufficient current carrying capacity, producing unintended heat and/or burning down the house. Use a high quality, heavy gauge cord as short as possible to eliminate this danger.

If you are charging at 120VAC you may draw as much as 12 amps.

 

[kevin]

I thank all participants for an excellent forum!

I ask if anyone can provide me guidance on the likelihood that I may, or may not, be able climb 4000 feet in a Spark. 25 miles relatively flat to gentle uphill and then another 25 climbing...up,down,up,down,up,up,down,up,up,up to 4000 feet.
...
bgs

What is the total elevation gain? Where are you going that is at 4000 feet?

I find that rollling hills don't affect range much.

When I go from Santa Cruz (sea level) to Los Gatos there is a climb of ~1800 feet over 15 miles that consumes ~5kWh. The remaining 7 miles down to Los Gatos (500 ft elevation) gets me about 0.4kWh back for a total of 4.5kWh for 22 miles. ~4.9mi/kWh.

This is in a 2014 Spark EV with speeds limited to ~50mph.

kevin

 

[DarrenDonovan]

The data from my commute may help you decide.
I go from flat land to 2500' in my daily commute, distance of 36 miles, 13 of those miles in a twisty canyon (lots of fun :mrgreen: ), the other 13 in gently up and down landscape. I don't drive "aggressively", but not hypermiling, either. In current weather (not hot summer temp) of 50 F in the morning and 75 F when I go home, I've been using anywhere from 11-11.5 kWH.

On the way home, I've been seeing 5.5-6.5 kWh used. Typically when I get to work, I'd have 4-5 bars left, plug it in for maybe 7 hours, when I get in the car to go home, I'd see 3 more bars added. This is charging at 12 amps, 120V outlet with the OEM cord. I always ended up in my driveway with 4 bars remaining, sometimes 5.

I think if you can do a test run, half way to your work destination (travelling to 2000' elevation) and see how much battery remains, then decide. If your drive is doable at all, I believe you'd need to drive "gently", certainly not at 60+ mph.

Good luck,

 

[SparkieVee]

It's definitely possible. http://www.mychevysparkev.com/forum/viewtopic.php?f=9&t=3811&hilit=mountain+climb&start=0 details a trip of 59 miles climbing 6500 feet. He did keep the speeds very low. 50 miles and less climbing should mean you'll be able to carry a little bit of speed.

Based on my own experience, I'd guess you could do it as long as you generally kept your speed to 65 or less. I live at 1800 feet and frequently visit relatives at the beach 30 miles away. Usually I leave the beach with 7 bars and drive back at freeway speeds, 70-75 halfway and 60-65 the other half, and can get home with 2-3 bars left. If I have 6 bars of battery left I keep it to 65-70 on the faster portion and can still get home with 2 bars left. The gentle slopes have a pretty minor impact on range, but at a 4% grade I'll see 2 miles of estimated range disappear every mile, and steeper slopes are far worse.

Depending on your speed, the temperature, and your use of heat/AC it's certainly possible, but I'd hesitate to recommend it if you're planning to drive 70 blasting the heat.

 

[Nashco]

Where are you at? A test drive might be the easiest and most accurate method to answer this question.

Bryce

 

[brunoylupe]

Thank you all for the detailed feedback.

The route is hwy 58, Bakersfield to Tehachapi. As the bird flies the elevation is about 3700 feet, but there are significant descents on the way up.

A test drive is absolutely the best, but i do not think my local dealer would be so excited about that.

I had the utmost confidence that i could do it, until I read that a 1200 foot descent will recharge the battery too fast and waste a lot of potential energy. .. or maybe i remember that wrong. ..

 

[Nashco]

A test drive is absolutely the best, but i do not think my local dealer would be so excited about that.

I think you're wrong. "I want to buy this car, but there's one critical thing I need to check first." I've taken lots of cars out for extended test drives, when you're shelling out tens of thousands of dollars, a four hour test drive isn't asking much. It costs the dealer zero dollars, also.

Alternatively, you could find a local Spark EV owner and ask if they'll try it in exchange for a nice meal. I'd certainly help if I was nearby, I'm always up for EV adventures.

I think you'd be hard pressed to lose much regen opportunity with the Spark EV. It's a fairly light car with as much as 60 kW of regen, which should do well to avoid the vast majority of loss to friction brakes.

Bryce

 

[TonyWilliams]

You can simply calculate the energy to go the distance, plus the additional energy required to make the climb.

I'll use 62mph, because I know that the Spark will consume 0.2kWh per mile (5 miles per kWh) on level, no wind, dry ground without the heater and a battery temperature of 70F degrees or higher.

So, the ultimate range in that scenario is:

2014 Spark EV - 18kWh usable * 5 = 90 miles

2015 Spark EV - 19kWh usable * 5 = 95 miles

Therefore, we need to reduce the usable capacity by the additional energy consumed.

One kilowatt hour = 2,655,224 pound feet of energy.

Driving your 3000 pound Electric vehicle up a 1000 foot elevation requires 3000 * 1000 = 3,000,000 foot pounds of energy divided by 2,655,224 equals 1.15kWh of energy to lift the car.

To raise the car 4000 feet is:

4000ft * 1.15kWh = 4.6kWh consumed

Therefore;

18kWh - 4.6kWh = 13.4kWh available / 0.2kWh =
19kWh - 4.6kWh = 14.4kWh available / 0.2kWh =

67 miles of range at 62mph while climbing 4000 feet (2015 Spark EV)
72 miles of range at 62mph while climbing 4000 feet (2014 Spark EV)

The dash economy would be at 62mph up the 4000 foot grade is:

67 / 18 = 3.7 miles per kWh (0.27 kWh per mile)

*******

If this is a daily commute, then I recommend adjusting your speed down as you need cabin heat, or if there's a headwind, or rain/snow/slush on the highway, and as the battery degrades.

In addition, it is highly recommended to preheat the cabin (and battery) anytime it is cold out.

Finally, I don't recommend using an extension cord. Instead, you might consider something like our JLong which can extend the length of the J1772 cord by 10 to 60 feet. You are fully protected by all the protections of J1772 (proximity disconnect, ground fault, pilot signal, etc).

Fully 40 amp capable, light weight and very portable.

 

[brunoylupe]

SIMPLY!
thank you for the help with the calculation.

I would not have set it up right.

bgs

 

[FutureFolly]

SIMPLY!
thank you for the help with the calculation.

I would not have set it up right.

bgs

Tony is using idealized math. Expect to lose efficiency while climbing in addition to the energy conserved by gravity.
If you're not trying to race up the mountain you should be fine. Also, the system almost certainly can't sustain peak power for that many miles so you couldn't really race up the mountain anyway.

If you want insight into how to hypermile the Spark EVs motor. Go to the preview in the link below and look at the last chart. You can see the efficiency never really drops below 90% at highway speeds, but never really exceeds 95% normally either. You won't need Plus battery and inverter efficiency will fall, but probably not as much as the motor. On a steep climb expect your efficiency to drop around 10%, so plan for %85-90 of Tony's idealized calculations.

http://papers.sae.org/2014-01-1806/

 

[DarrenDonovan]

brunoylupe,

I may be able to help get some concrete information for you! :mrgreen: I live in Bakersfield, and the commute I described is on Highway 178 up to Lake Isabella. Let me have your exact route, and I'll find some time to drive it and report back.

 

[brunoylupe]

SW Bakersfield is my start, over by the high school. 58 from Comanche to Tehachapi is the part that would interest me the most. I may have been going a little faster than an EV, but that is about my halfway point. At least 9-12 min. to the 99, depending on the red and green lights...

The back way from Keene up Woodford-Tehachapi might be safer, 50 mph, or less, sounds like roadkill on 58.

After reading of the trip to Kennedy Meadows, and seeing the calculations (and amendments), I am very optimistic. I think it will make it now, but the time/speed may be the most important consideration.

I may have to leave significantly earlier...!?

bgs

 

[DarrenDonovan]

SW Bakersfield is my start, over by the high school. 58 from Comanche to Tehachapi is the part that would interest me the most. I may have been going a little faster than an EV, but that is about my halfway point. At least 9-12 min. to the 99, depending on the red and green lights...

The back way from Keene up Woodford-Tehachapi might be safer, 50 mph, or less, sounds like roadkill on 58.

After reading of the trip to Kennedy Meadows, and seeing the calculations (and amendments), I am very optimistic. I think it will make it now, but the time/speed may be the most important consideration.

I may have to leave significantly earlier...!?

bgs

Do you still want me to drive the underlined route for you? If yes, which exit in Tehachapi should I get off?

 

[brunoylupe]

The first exit, hwy 202, at the top of the hill, is typically where I exit, my office is about 5 miles from there. If you are curious too, by all means, I would like to know with certainty. BUT, until I feel more confident, I would plan to charge in Tehachapi. If it looks too close, Broome rd. exit is an easy turnaround just above 3000 ft and about 5 miles down the hill. Making it up is one thing, coming back down on a depleted battery is just plain thrill-seeking! From what I have read it seems the descent and regeneration would buy some free miles, however, I am not familiar enough to know if it would be enough to get home.

[email protected]

bgs

 

[brunoylupe]

DONE!

Up to the top and back down again.

88.3 miles
6.3 mi/kWh

 

[TonyWilliams]

DONE!

Up to the top and back down again.

88.3 miles
6.3 mi/kWh

Interesting. Is there any chance that you saw the miles/kWh at the top of the hill?

 

[brunoylupe]

Max miles at the top were 29 (3 bars), 17 when I got home (2 bars)! To the top of Woodford - Tehachapi.

 

[FutureFolly]

Was this done in a 2014 or 2015 Spark EV?

 

[brunoylupe]

2015