Get Spark to go 100 miles?

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CSW

Well-known member
Joined
Feb 17, 2015
Messages
198
Location
Sacramento,CA
What would it take to be able to get the spark to go 100 miles on a charge? Assuming flat ground and moderate temps, what speed would you need to go? Askin in another way, what would you want your kwh usage to be as you are travelling along to make it to 100 miles? 45mph? 8kwh?

Why do I ask? Because I need to do it to make it somewhere I would like to challenge the spark to do..... not sure if it can
be done.

My battery has about 17.5kwh useable , I would need to achieve about 5.8kwh/mi efficiency.
 
Lots of stop and go driving in L.

I have a pretty flat 40 mile commute each way. Elevation change of about 200 feet with very little climbing or drops. In rush hour LA traffic where I'm getting regular regen for about half the drive, I often get 6.0+ m/kWh. So if you have 17.5 usable, 6.0 gets you over 100.

Best I ever did was 114 on a single charge. With 17.5 usable 100 miles is definitely doable. This assumes you're not running climate control except just the fan for fresh air.
 
Living on the peninsula, San Mateo County, with 15000 miles I have 5.9 m/kwh. 90% of my driving in at speeds lower than 50 mph. I regularly get 7+ running around town for 20 or so miles per trip.
100 miles sounds easy.
 
23 MPH set the record sometime back. Look it up.
So play it safe.
As slow as possible.
Is 25 MPH the slowest the Cruise Control will set at?

So play it safe,,, and legal.
Get the Red Triangle for the back of your car, like the Amish horse carriages use.
 
Haha! Red triangle. Or leave the hazard lights on the whole time.

The run I need to to is all 2 lane highway with pretty much zero stops and very little traffic.

The speed limit has got to be at least 55 if not 65.

I bet if I could do 45 most the way I could prob make it, just pull over if somebody gets behind me.
 
You've done half the math.

Best bet is to do a trial run on the flat and see what your average kW consumption is at various speeds. Build in a safety margin for your trip, perhaps 5 or 10 MPH slower than your calculated speed.

Here's a graph put together by Bob Wilson for a BMW i3. Looks like somewhere around 45 MPH would be close.

If the wind varies even by a few MPH, that can drastically affect your calculated efficiency. Make sure someone at the other end has a tow rope just in case.

i3_rex_030.jpg


SilentGreen said:
Lots of stop and go driving in L.
In rush hour LA traffic where I'm getting regular regen for about half the drive, I often get 6.0+ m/kWh.

Just to clarify for others, the efficiency is not from "stopping and going" but from traveling at a slow average speed. You'd get even better efficiency if you drove that same low average speed with no stopping.
 
Try increasing your tire pressure. I went to 45 psi and am able to get 5 miles/kw @ 55mph on the freeway. Best before was 4 miles/kw at the same speed. More tire pressure = less rolling resistance. You could also try drafting semi's if your feeling adventurous/lucky.
 
boatbum11 said:
Try increasing your tire pressure. I went to 45 psi and am able to get 5 miles/kw @ 55mph on the freeway. Best before was 4 miles/kw at the same speed. More tire pressure = less rolling resistance. You could also try drafting semi's if your feeling adventurous/lucky.

haha! they call that "rolling on rocks" with you tires that high in psi.
But yes, I will do that, maybe put then to 42 psi to account for them heating up while driving as the max psi
on these factory tires is 44.

I have tried the drafting thing and you gotta way close to catch the draft..... i am lucky and i don't wanna burn up all my luck on drafing.
 
As far as tire pressure is concerned, efficiency improves with diminishing returns as it is increased. In other words, going from 30 PSI to 40 will improve efficiency much more than going from 40 PSI to 50.

That said, there is no risk of bursting the tire due to over-inflation. It takes several hundred PSI to burst a tire. I'd air them up to whatever you can tolerate, as the ride gets harsher the higher the pressure.
 
CSW said:
I have tried the drafting thing and you gotta way close to catch the draft..... i am lucky and i don't wanna burn up all my luck on drafing.
Actually I don't think that's true. Yes, the ideal draft is too close for safety - if you could keep it 5 feet from the back bumper of a semi going 50 I'd bet you could make 200 miles. But a respectful following distance will still give you a significant range boost. I commute by bike and I can easily feel the effect of a city bus going 35 when it's a city block away.

I've done over 100 miles several times, mostly by following trucks at a reasonable distance. If I can find a truck going about 60 I'm all set. With nobody to follow, going much above 50 makes it tough. I will say that it was easier in the 2014 Spark than the 2016 as the gearing was better-suited to higher speeds.

When I'm stretching the range, I pay attention to the battery bars in the instrument cluster. If it's pretty flat, they can give you a good idea of how you're doing. You just need each bar to last you more than 10 miles. If they don't, slow down. Keeping the energy usage under 10kW is also a good goal.
 
CSW said:
boatbum11 said:
Try increasing your tire pressure. I went to 45 psi and am able to get 5 miles/kw @ 55mph on the freeway. Best before was 4 miles/kw at the same speed. More tire pressure = less rolling resistance. You could also try drafting semi's if your feeling adventurous/lucky.

haha! they call that "rolling on rocks" with you tires that high in psi.
But yes, I will do that, maybe put then to 42 psi to account for them heating up while driving as the max psi
on these factory tires is 44.

I have tried the drafting thing and you gotta way close to catch the draft..... i am lucky and i don't wanna burn up all my luck on drafing.

Actually I haven't notice any real change in ride. However the road noise increased markedly!! Also I use cruise control and drive in D on the freeway. At 55 I see 10-11kw consumption on the display on level ground with no headwind, though my Spark is a 2014 with the taller gearing.
 
CSW said:
At 55 I see 10-11kw consumption on the display on level ground with no headwind, though my Spark is a 2014 with the taller gearing.

That's 1 data point! You said the battery holds 17.5 kWh.

17.5 kWh / 10 kw = 1.75 hours of driving @ 55 MPH
1.75 hours of driving @ 55 MPH = 96.25 miles

You're almost at your 100 mile target by driving 55 MPH if our assumptions are correct.

Using your 11 kW consumption rate, the math is:

17.5 kWh / 11 kw = 1.59 hours of driving @ 55 MPH
1.59 hours of driving @ 55 MPH = 87.5 miles

Take a kW reading at each 5 MPH increment and plot it.

My guess is somewhere around 45 MPH makes the 100 mile trip doable.
 
Sparky gave me 96 miles in the blue circle yesterday and 98 today. Both commutes were the first and second time I had done my ~63 mile commute with less than 10kw (9.9 & 9.8 respectively). That 63 miles is ~44 miles interstate (keeping it 60-62mph unless I'm going uphill or following another slow vehicle at a proper/safe distance), ~7 miles on two lane country roads (45-55mph), and 12 miles on 35mph city streets. My tire pressure is 41psi cold, 46 hot.

I have somewhere between 16-16.5kwh usable. I believe I agree with Redpoint, with an average trip speed around 45mph, favorable conditions, and competent driving, there should be no reason not to go beyond 100 miles, even with a slightly degraded battery pack.
 
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