# Finished conversion efficiency (Wh/mile)



## pcsrule (Dec 14, 2012)

I just ordered my lithium pack and in about 5 weeks I will be dropping about 1,200 pounds of lead batteries out of my converted RAV4. While the lead batteries were still working I recorded an average efficiency of about 300 watt-hours per mile and I of course expect this to go down a bit due to the decreased weight. I'm using an Azure dynamics AC-55 motor and DMOC445 controller with regenerative breaking (recuperated energy is included in the average above). The car weighs about 4,000 pounds total with all of the lead and the driving speed during measurement was 30-40mph on average. I used a relatively heavy right foot in order to make this a conservative estimate. The calculation was done by logging the ammeter and voltmeter in the car, then integrating to get total energy used. This was divided by the distance traveled on my trip meter.

I've seen everything from 200-350 Watt hours per mile quoted in various places so my question for you is what efficiency are you getting from your conversion. at least those that have the ability/know how to measure/calculate their energy consumption per mile. About how much does your car weigh, average driving speed, heavy foot, etc are also good bits of information to include. This should help everyone get an idea of what to expect and help to figure out how much capacity is needed for those designing battery packs.

Thanks.


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## Ziggythewiz (May 16, 2010)

I get 230-280 wh/m with 2900 lbsish. Semi-lead foot on accelerator, helium foot on break.


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## tomofreno (Mar 3, 2009)

http://www.diyelectriccar.com/forums/showpost.php?p=335188&postcount=656
SwiftE in the "garage".


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## rwaudio (May 22, 2008)

300wh/mile for a 2800lb car, mixed city/highway/small hills with "spirited" driving. 250wh/mile same route as above but driving more conservatively, far from "hypermiling" just no full throttle starts.

Not hard to average 350+wh/mile with more stop and go, and fast acceleration.

So a good portion of your final energy usage comes down to how you drive. If all else is the same you should get better "mileage" with stop and go driving but very similar highway "mileage".


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## azdeltawye (Dec 30, 2008)

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


Total miles on conversion (as of *12/1/2012*) = *26,618 *miles
Total number of charge/discharge cycles to date = *748 *cycles
Total AC Watt-hours consumed to date = *10,178.2* kWh
Overall average AC energy consumption rate = *382.4* Wh/mi
Total DC Watt-hours received by battery to date = *9,270.1* kWh
Total DC Watt-hours delivered by battery to date = *8,685.3* kWh
Overall average DC energy consumption rate = *326.3* Wh/mi
Overall average battery efficiency (DC Wh out / DC Wh in) = *93.7*%


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## Ziggythewiz (May 16, 2010)

Those are some good numbers. One of my new year's resolutions is to keep better records.


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## dougingraham (Jul 26, 2011)

2200 lbs and measured at the wall with a Killawatt meter I see around 310 wh/mile. If measured on the battery side of the charger It is about 265 wh/mile. You need to watch where this number is measured. This makes perfect sense as the charger is about 85% efficient. This is city driving only and I know the car needs some work. I think the brake pads are all dragging. I am hoping to see post charger efficiency of closer to 200 wh/mile after I get the bugs worked out.


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## RogerK (Dec 20, 2011)

I have a converter 1988 Goldwing. I am getting about 125 WH/Mile. I use 24 LiFoPo, 70 AH batteries. I've heard that a gallon of gas is about 8000 W. So my bike has the equivilent of nearly 3/4 a gallon of gas on board. Makes sense since a Golwing can get about 60 MPG if taking it very easy, so my electric goldwing gets .72 of that, or 43 miles. Thats about what I get. My dream is to pull a generator for extended range.


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## dtbaker (Jan 5, 2008)

first.... ya gotta clarify whether you are looking at consumption from the wall, or traction pack after the energy is IN and only talking about operational efficiency.

I found a big difference from lead to lithium just in the charge cycle since there is no gassing cycle for the lithium (hopefully!). There is still loss in the charge cycle both from the charge, and even the extension cord! It gets warm.... thus is losing something between the wall and the batteries.

I would also say that how heavy your foot is matters more with lead than Li.... as the more amps exacerbate peukarts effect in the Pb. Also affected by the additional weight accelerating.

All that being said.... in my case with the Swift (8"DC motor, curtis 1221 controller) when it was a 96v lead ev I used an average of 400 wH/mile from the wall, and roughly 275wH/mile guessimate in actual operational use looking at average amps*voltage pulled at average speed around town.

same car upgraded to 120v x 100ah li pulls average of 300 wHr /mile from wall, and slightly less operationally as well probably closer to 225-250 from the pack.


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## swoozle (Nov 13, 2011)

2500 lbs, Warp 9 motor, 154V 20kwh lifepo pack.
I get much better mileage on the freeway: ~280 wh/mile (from the battery, not the wall)
As bad as 500 wh/mile around town, depending.


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