# [EVDL] ICE mpg vs EV watts per mile



## EVDL List (Jul 27, 2007)

Can only comment on my experience. A Civic does
between 225 and 300 Wh/mi.



> --- Dave Delman <[email protected]> wrote:
> 
> > Is there a general formula for estimating how many
> > watts per mile you'll need when you convert to
> ...


----------



## EVDL List (Jul 27, 2007)

A few years ago I compared the posted WH/Mile of several dozen EVs to
their previous MPG and came up with a rough formula

10 kwh (from the outlet) = 1 gallon of gas (assumes Lead-Acid batteries)

However EVers tend to be very optimistic about their kwh used and often
forget to add in the energy used for equalization charging.

On the flip side, there are chargers available now that are more efficient
that the ones 10 years ago, and a good BMS can reduce the energy wasted
for equalization.



> Is there a general formula for estimating how many watts per mile you'll
> need when you convert to electric from an ICE vehicle that got X mpg?
>
> A DeLorean typically gets 20 mpg. I seems to need 125 battery amps at
> about 150 volts to go 60 mph. Does that mean I am using 150 x 125 =
> 18,750 watts (then divided by 60 miles in one hour) or approx 312 watts
> per mile?
>
> At 20 cents per KW here in Long Island, NY that's 6.25 cents (x some
> charger efficiency #) /mile.
>
> At 20mpg and $3.20 / gallon of gasoline = 20 cents per mile.
>
> Does this seem correct?
>
> Dave Delman
> electricdelorean.com
> Still working on building a proper charger...
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> At 20 cents per KW here in Long Island, NY that's 6.25 cents (x some
> charger efficiency #) /mile.

Oh yeah...

Charge efficiency for Lead-Acid batteries is roughly 75%-80%, Typical EV
chargers are about 80%, so total of about 60% efficiency

So you're probably pulling about 500 wh/mile from the outlet.

If you use 110V charger, you can pickup a kilawatt meter cheap (about $40)
and actually measure the power going into your vehicle.


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

To compute the watts per mile, use the charger input kwr input. If I charge 
at 240 vac at 50 amps for one hour for 30 miles at 30 mph, than this would 
be about (240 x 50)/30 = 400 wh/mi.

Now if I use my actual Emeter readout, this becomes about (180V x 50A)/30M = 
300 wh/mi.

I found one of the reason for the difference, is that the DC-DC converters 
and DC-AC inverters were connected between the battery shunt and the 
batteries, which did not show up as the total battery usage on the Emeter 
and the charger current is about 10 percent more input than you take out.

To compare EV watt per mile usage, you have to have the EV's driving in the 
exact same conditions. For example, if I drive in the north direction from 
my home for one mile, it takes exactly twice the energy than if I drove one 
mile south from my home.

Now if I drive east or west, than it takes 1/4 more then the north direction 
or 1/4 less than the south direction which is the 400 wh/mi at 30 mph.

Roland




----- Original Message ----- 
From: "Bob Bath" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, February 28, 2008 7:18 AM
Subject: Re: [EVDL] ICE mpg vs EV watts per mile


> Can only comment on my experience. A Civic does
> between 225 and 300 Wh/mi.
>


> > --- Dave Delman <[email protected]> wrote:
> >
> > > Is there a general formula for estimating how many
> > > watts per mile you'll need when you convert to
> ...


----------



## EVDL List (Jul 27, 2007)

> On 28 Feb 2008 at 8:55, someone wrote:
> 
> > watts per mile
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Peter VanDerWal wrote:
> 
> >If you use 110V charger, you can pickup a kilawatt meter cheap (about $40)
> >and actually measure the power going into your vehicle.
> ...


----------



## EVDL List (Jul 27, 2007)

Anyone ever open up one of those Kill A Watt meters to see if you could hook 
up 2 whn on 220VAC?




Thank you,

Dave Delman
1981 Electric DeLorean Project
electricdelorean.com



**************Ideas to please picky eaters. Watch video on AOL Living. 
(http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/
2050827?NCID=aolcmp00300000002598)
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> On 29 Feb 2008 at 22:33, [email protected] wrote:
> 
> > Anyone ever open up one of those Kill A Watt meters to see if you could hook
> > up 2 whn on 220VAC?
> ...


----------



## EVDL List (Jul 27, 2007)

That watt hour meter is no longer available on eBay.

I bought it!

Thanks David for the info.

There are other available...



Thank you,

Dave Delman
1981 Electric DeLorean Project
electricdelorean.com



**************Ideas to please picky eaters. Watch video on AOL Living. 
(http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-duffy/
2050827?NCID=aolcmp00300000002598)
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Hialeah meter company has lots of refurbished (or new) utility type kWh
meters, and bases. Less than $60 for a basic 240vac meter and socket IIRC.

Z

On Fri, Feb 29, 2008 at 11:31 PM, EVDL Administrator <[email protected]>


> wrote:
> 
> > On 29 Feb 2008 at 22:33, [email protected]
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Electric DeLorean wrote:
> >
> > Is there a general formula for estimating how many watts per mile you'll
> > need when you convert to electric from an ICE vehicle that got X mpg?
> ...


----------

