# Whrs/Miles



## Dustin_mud (May 22, 2012)

I couldn't find a thread on this so here we go, what do you average on your whrs per mile?

Add info on your Ev type and driving environment.


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## PThompson509 (Jul 9, 2009)

I range from 300 to 350 Wh/mi. 350 is when I'm keeping up with traffic on the freeway (no need to mention the actual speed is there?)  Usually a mix of freeway and city driving (San Diego).

1975 Porsche 914, 22KWh pack, 370v nominal, 80 KW BLDC motor.


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## sunworksco (Sep 8, 2008)

Where can I see photos of your 914?
How much does it weigh?


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## PThompson509 (Jul 9, 2009)

I've kept a blog of the conversion: http://cruzware.com/peter/blog

It weighs around 2200 pounds (took it to a truck weighing station). Zero weight gain.


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## sunworksco (Sep 8, 2008)

Wow!
Good job on the weight.


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## madderscience (Jun 28, 2008)

my 2004 scion xB conversion gets between 250-275wh/mile battery to wheels at 60mph cruise depending on conditions. City driving is similar because the regen helps out more. 

Measurements using an elithion bms. These are winter numbers, I expect summer numbers may be as much as 10% better based on my experience with my old MR2 conversion.

It's boxy, but its lowered, and I've got the rolling resistance dialed in pretty well. 3040lbs curb weight, by local truck scale. LRR 51psi tires. Solectria AC55/UMOC direct drive drivetrain.


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## PhantomPholly (Aug 20, 2008)

Since energy use varies considerably with driving conditions, a while back I asked the folks on this forum how much storage was roughly equivalent to 1 gallon of gasoline for purposes of propulsion.

The consensus came in at about 8Kwh = 1 gallon, allowing for no more than 80% DOD and understanding that it doesn't scale very well (too many batteries add so much weight that you encounter diminishing returns).


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## glyndwr1998 (Apr 27, 2013)

Hi,

I have a toyota prius with a plug in hybrid kit fitted and a 5kwh lifepo4 pack.

On recent tests in the uk in cold and hilly terrain conditions, I used average of 400wh/mile.

Also, I have had a nissan leaf for 2 days trial, and that averaged 290 wh/ mile in Eco mode with no heating or air con.

Anthony.


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## dougingraham (Jul 26, 2011)

You have to be careful on how you measure it. If I go by what the charger says for AH and multiply that by the battery voltage I get a better number than what the killawatt meter shows. I prefer the killawatt meter number which can be directly equated to cost.

My car weighs 2400 lbs and my best ever wh/mile number is 298. My worst ever was 521. The calculated from AH numbers are about 15% better so those are 253 and 442.


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## elevatorguy (Jul 26, 2007)

I use the AH meter in the car and get 275 to 350 in the warm season. I really don't drive it much in the winter because the heater isn't installed yet.
The vehicle weighs 2850 and most the driving is not above 60 mph.


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## rmay635703 (Oct 23, 2008)

The best I have done is around 130wt/mile (very low speeds) on a miles zx40

Normally it averages around 150wthr/mile Its a 2300lb kei van and it usually is driving about 25mph and has a whopping 275amp peak controller 

Oh and I do keep 50-60psi in the tires.


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## Karter2 (Nov 17, 2011)

OK, i can see that we have to start somewhere, and this is a good beginning.
But without more data to go with the Whr/mile it can be very misleading.
Vehicle model, weight, average speed, drive package ( AC, DC, Voltage etc), type of driving ( City, highway, steady, flat, hills, ? ) ....all can have a significant effect on the data, 
So, be aware, and add as much info as you can,..
..otherwise its like blindly asking everyone what gas mileage they get !


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## PhantomPholly (Aug 20, 2008)

Like I said earlier, just use 8Kwh = 1 gallon of gas. Then adjust for vehicle weight, driving conditions, and overall vehicle efficiency (drag, etc.). You'll come out close enough for planning.


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## Frank (Dec 6, 2008)

Are you saying that if an ICE vehicle gets 32 mpg that one can expect to consumer 8kwh to travel the same distance?


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## dougingraham (Jul 26, 2011)

Frank said:


> Are you saying that if an ICE vehicle gets 32 mpg that one can expect to consumer 8kwh to travel the same distance?


Yes, that is what PP is saying. If one gallon of gas with typical automobile efficiency = 8kwh then 8000/32 = 250wh/mile which is a reasonable number.

If you get 16mpg then this would be 500 wh/mi. If you get 8mpg it is 1000 wh/mi.

It is just another way to estimate it.


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## PhantomPholly (Aug 20, 2008)

dougingraham said:


> Yes, that is what PP is saying. If one gallon of gas with typical automobile efficiency = 8kwh then 8000/32 = 250wh/mile which is a reasonable number.
> 
> If you get 16mpg then this would be 500 wh/mi. If you get 8mpg it is 1000 wh/mi.
> 
> It is just another way to estimate it.


Exactly. Since most people doing conversions are converting a car which already has a known mileage while they personally are driving it, it is simpler to use and "equivalency test." 8Kwh/gallon appears to be a conservative approximation, leaving some overhead so as not to overdrain the batteries for the specified number of miles.

Caveat - for every extra "gallon" of batteries you can expect diminishing returns from "parasite weight."


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## Frank (Dec 6, 2008)

I figured that was what you were trying to convey, 250 wh/mi is indeed a decent number to use. My concern was that someone might assume one gallon of gasoline is equivalent to 8 kWh energy because it most certainly is not! This conversion demonstrates the lousy efficiency of the ICE as we all know 1 US gal. contains about 32 kWh energy. I just wanted to clarify the point for someone perusing the thread.


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## Karter2 (Nov 17, 2011)

But that assumes the converted vehicle will weigh the same, perform the same, and be driven in the same way, as the ICE version.


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## PStechPaul (May 1, 2012)

An EV would be expected to give as good or better energy efficiency as the highway MPG. My Saturn averages 35 MPG and I have seen 45 MPG on long trips at moderate highway speeds. I think it might get as much as 50-60 MPG on flat roads at 40 MPH. That would be the equivalent of better than 160 Wh/mile based on the 25% ICE efficiency using the 8kWh/gallon figure.

Again I will use my EV calculator to see how this pans out. I'll use 2500 lb for the vehicle weight including me and Muttley and normal cargo for a weekend trip. I'll use the default coefficient of rolling resistance 0.02, a CD of 0.25, frontal area of 1.25 m^2, and 40 MPH, with a constant acceleration of 0.1 m/sec/sec which is a steady 1% grade. I get 179 Wh/mile, which is pretty close to my estimate above.

At 60 MPH I get 212 Wh/mile, which is about 37.7 MPG. Pretty close. For driving in Kansas, I get 161 Wh/mile or almost 50 MPG.

As for cost, my ICE vehicle costs me about $0.10/mile for gas at $3.50/gallon. For electricity, at $0.12/kWh, and 250 Wh/mile, it would cost about $0.03/mile. But if I must replace a 16 kWh (64 mile) battery pack after 10 years or 100,000 miles, at about $5000, it adds another $0.05/mile, or $0.08 compared to $0.10.


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## gunnarhs (Apr 24, 2012)

Dustin_mud said:


> I couldn't find a thread on this so here we go, what do you average on your whrs per mile?
> Add info on your Ev type and driving environment.


Assuming 1 mile = 1,6 km.
Assuming normal conditions in Iceland 
(temperature 5 -15 Celcius degree, no storm).
Assuming average driving speed 70 km/h, mostly flat but hills up and down (+-4%)

Commercial cars:
Mitsubishi MIEV 300Wh/mile (5km/kWh <). Car is somewhat over 1000 kg, Motor 40 kW (max)
Tesla S 320Wh/mile (5km/kWh) Car is almost 2000 kg(!)
Nissan Leaf 320Wh/mile (5km/kWh) Car is about 1400 kg. Motor 80 kW (??????max)

Semi-Commercial (older car improved with new battery/controller)
Peugeot 106 200Wh/mile (8km/kWh) Car is about 1250 kg (*) SepExDC Motor 20 kW (max)
(*) No electrical heating, Webasto gasoline

Converted cars:
Daewoo Lanos 320Wh/mile (5km/kWh). Car is about 1100 kg, Serial DC, Motor 40 kW (max)
Suzuki Wagon R 200Wh/mile (8km/kWh) Car is about 1200 kg(**), Induction Motor 30 kW (max)
(*) No electrical heating,
(**) No electrical heating. Induction Motor result improved with better control-box.

Clarification of the results:

Best Wh/mile/kg: 
The best seems to be 160Wh/mile (10km/kWh) per 1000 kg, 70 km/h average)

1) Tesla S by far. Has all comfort,best driving behavior, no compromise car
2) Suzuki Wagon R Good range , rather lame driving, no comfort
3) Peugeot 106 Very good range , very lame driving, ok comfort.
4) Nissan Leaf Has all comfort. Lame range, good low speed acceleration, lame high speed acceleration, lame uphill over 60 km/h
5) Daewoo Lanos. Not worse driving than Nissan, but same range and less comfort. Nissan much better in lower speeds, lanos better over 60 km/h
6) Mitsubishi MIEV. No comfort, bad heater, lame range, bad battery loading during cold climate . Will hopefully not be continued

Best car overall
1) Tesla S by far. 
2) Nissan Leaf. Good but disappointing at higher speeds, not suitable for Autobahn in Europe
3) Daewoo Lanos. Best conversion for the money spent.

The others were not good (yet )


What (probably)affects range most:
1) Electrical heating up to 20% (at least when getting under 10 C). 
2) Cold batteries (additional 10-20%)
3) Forced liquid cooling of inverter/motor (10-15%)
4) Bad control behavior (for Induction motor and Sepex-DC up to 20%)


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## VWKASTER (Nov 23, 2011)

I'm new here and working on a 1400lb vehicle that only needs to achieve 40 mph for 30 miles. Is there a simple formula to estimate how much battery pack I'll need? Thanks!


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## PStechPaul (May 1, 2012)

```
250 Wh/mile * 30 miles = 7.5 kWh
 
Multiply by 1.33 for 75% DOD => 10 kWh
```
"YMMV" 

My EV calculator comes up with 133 wH/mile, with a 1% continuous slope, but does not account for efficiency. At 80% overall efficiency that would be 133/0.8 = 166. I chose 250 because that is a typical value for DIY conversions. Your vehicle is lighter than most, and also going slower than most, so it will probably do better.

There are too many variables to make a really accurate recommendation, but for a typical EV, especially at 40 MPH, that is a conservative estimate. Your driving style will also greatly affect the numbers. Also, this assumes LiFePO4. If you use lead, add about 50%, for 15 kWh.


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## VWKASTER (Nov 23, 2011)

Thanks for the wh/mile and battery pack estimate. Seems like someone should be able to make a set of graphs to use to estimate this. Is there such a set? I'm just in the design stages of this project and already discouraged by the cost of LiFePo4 to achieve 15kWh. I guess I should move to motors and voltages next. Has anyone worked with wheel motors? My project is a reverse trike, light weight and there is one org that makes wheel motors for motorcycles. Ener... Anyone with experieince with these?


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## azdeltawye (Dec 30, 2008)

Dustin_mud said:


> I couldn't find a thread on this so here we go, what do you average on your whrs per mile?
> Add info on your Ev type and driving environment.


 Vehicle: 2001 WV Jetta
Curb Weight: 3540 lbs 
Driving style: Normal stop-and-go city with occasional hwy


Total miles on conversion (as of 2/7/2014) = 40,102 miles
Total number of charge/discharge cycles to date = 1,100 cycles
Total AC Watt-hours consumed to date = 15,512 kWh
Overall average AC energy consumption rate = 386.8 Wh/mi (all AC Wh / all miles)
Total DC Watt-hours received by battery to date = 14,206 kWh
Total DC Watt-hours delivered by battery to date = 13,254 kWh
Overall average DC energy consumption rate = 330.5 Wh/mi (all DC Wh delivered / all miles)
Energy storage efficiency of battery (DC Wh out / DC Wh in) = 93.3%
 
Vehicle Location: Tucson, Arizona
Climate data for Tucson:


Average annual temperature = 68.4⁰F
Annual heating degree days = 1678
Annual cooling degree days = 2954


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## vmrod (Jul 2, 2010)

Not to hijack the thread...but go check out my electric reverse trike construction blog.

http://xr3.proboards.com/

I did not go cheap with the parts. Have spent over 20k so far. Lots of fun!





VWKASTER said:


> Thanks for the wh/mile and battery pack estimate. Seems like someone should be able to make a set of graphs to use to estimate this. Is there such a set? I'm just in the design stages of this project and already discouraged by the cost of LiFePo4 to achieve 15kWh. I guess I should move to motors and voltages next. Has anyone worked with wheel motors? My project is a reverse trike, light weight and there is one org that makes wheel motors for motorcycles. Ener... Anyone with experieince with these?


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