# EV Mileage Performance miles per hour



## cts_casemod (Aug 23, 2012)

*EV Mileage Performance miles per kw/h*

After some tests with my car I found my mileage to be 300Wh per mile with only me and my daughter and 350Wh/M with me, my wife, daughter and full shopping trolley inside, driving in city with moderate to low traffic.

These are values from the socket and include the 12V circuit with headlights, power steering... no heating, yet...

I do good use of regenerative braking.

My car weights 750Kg.

Now what I don't understand is how I see DC conversions claiming 250Wh from the wall. Both my motor and controller are not actively cooled (No fans) so i don't believe I am loosing much power as heat. Batteries are cold to touch as well.

What average do you guys get? Does that take into account more than one person inside the car?

I am thinking in changing my 185 65 R14 tires for 175 70 R13. 
Is there any advantage by doing so?


----------



## Ziggythewiz (May 16, 2010)

Mine was 250 wH/m from the wall when new, and that was with 600 lbs lead (~2200 lbs?). ACC power is negligible/solar.

Now with half a ton of batteries and stupid disc brakes I'm around 260-280 wH/m from the batteries (and I've seen as low as 230) and ~360-410 wH/m from the wall.

A small car with lithium could easily get under 250 wH/m from the wall.


----------



## cts_casemod (Aug 23, 2012)

Ziggythewiz said:


> Mine was 250 wH/m from the wall when new, and that was with 600 lbs lead (~2200 lbs?). ACC power is negligible/solar.
> 
> Now with half a ton of batteries and stupid disc brakes I'm around 260-280 wH/m from the batteries (and I've seen as low as 230) and ~360-410 wH/m from the wall.
> 
> A small car with lithium could easily get under 250 wH/m from the wall.


Thanks. Bare in mind I only drive inside the city with frequent stops for lights, etc. Infact, I think my decision to keep the flywheel/cluch was not the best for city driving as it uses a considerable ammount of energy for acceleration under low gears. Acessory power on mine is quite significant, about 10-13%.

Ill need to get the gear linkage done to see if that will improve things but I was having similar mileage using 2nd gear only (now using 3rd)


----------



## Ziggythewiz (May 16, 2010)

Even without a clutch stop and go takes a lot. I use a disproportionate amount of energy in the first mile at 30 mph. I've read that higher gears take more power, not sure why. In the limited testing I've done I use 20% more in 3rd than 2nd.


----------



## corbin (Apr 6, 2010)

*Re: EV Mileage Performance miles per kw/h*



cts_casemod said:


> After some tests with my car I found my mileage to be 300Wh per mile with only me and my daughter and 350Wh/M with me, my wife, daughter and full shopping trolley inside, driving in city with moderate to low traffic.
> 
> These are values from the socket and include the 12V circuit with headlights, power steering... no heating, yet...
> 
> ...


Most people only post their best results. On average, 300-350 wh/mile seems much more common than 250. To get 250wh/mile you have to drive slow (less than 50 mph), slow acceleration in particular, don’t drive up hills, and with not much weight in the car.

Even in my bug, which is light, I would probably never get 250wh/mile from the wall. I don’t really care about the wall number; I care more about how much energy it takes from the battery while driving, as that tells you your range. 

See my blog for details on my car and wh/mile calculations.

-corbin


----------



## dladd (Jun 1, 2011)

I _can_ get 250Wh/mi from battery to wheels (not AC input), but I don't.  It's usually more like 310Wh/mi (cause I just drive normal, not with an intent on efficiency). Lately it's been closer to 350 with the cold weather. I've seen over 400Wh/mi with heater usage! Add ~15% to those numbers for my 'from the wall' numbers.

fwiw, I get about the same efficiency around town and on the highway. It all pretty well averages out to just over 300Wh/mi (again, battery to wheels, not input power).

This with a basic DC system, lithium cells, and a total weight a bit under 3000 pounds.


----------



## cts_casemod (Aug 23, 2012)

*Re: EV Mileage Performance miles per kw/h*



corbin said:


> Most people only post their best results. On average, 300-350 wh/mile seems much more common than 250. To get 250wh/mile you have to drive slow (less than 50 mph), slow acceleration in particular, don’t drive up hills, and with not much weight in the car.
> 
> Even in my bug, which is light, I would probably never get 250wh/mile from the wall. I don’t really care about the wall number; I care more about how much energy it takes from the battery while driving, as that tells you your range.
> 
> ...


 
I believe so. I see a lot of bikes having 150Wh/m. In fact my bycicle with brushless DC uses 36WH/M frm the battery, at just over 100Kg, but I had a DC version before with a 1HP motor that would duse 70WH/M with lead acid (Actual values from the battery, not from the wall) so i find a bit odd some references I find of 180 to 200Wh/m even with lithium

I get a worse case scenario of 350, but obviously thats not how much i have at the wheels due to voltage sag and battery charging losses. I have done 240 from the wall driving alone in the car with low traffic and a dedicated 12V battery. I have 30-40V of sag under full aceleration at 8C discharge rate depensing on battery soc. Upgrading the pack might benefit this.

On the other end, being that i dont use the brakes att all due to regen and given the fact my car weights just over 1500 pounds without great acceleration and the charger is 97% efficient leaves me thinking.



dladd said:


> I _can_ get 250Wh/mi from battery to wheels (not AC input), but I don't.  It's usually more like 310Wh/mi (cause I just drive normal, not with an intent on efficiency). Lately it's been closer to 350 with the cold weather. I've seen over 400Wh/mi with heater usage! Add ~15% to those numbers for my 'from the wall' numbers.
> 
> fwiw, I get about the same efficiency around town and on the highway. It all pretty well averages out to just over 300Wh/mi (again, battery to wheels, not input power).
> 
> This with a basic DC system, lithium cells, and a total weight a bit under 3000 pounds.


I have an issue with the AC motor: Fixed Volts per revolution and fixed torque boost. Is fine if you want to accelerate quickly but its a waste to pump 70V to the motor to drive at 5MPH or to cruise.

400 with heater is actually pretty good!

In my AC system it may use, but I am limited by my throttle to about 70Hz or 1900RPM. I have to get a hall sensor type to have the full range. Its more complicated that a DC and unlike the fuji this unit I use now is quite limited in terms of options.

As with the clutch the issue is having a 14KG flywheel going from 0 to max RPM. This alone requires a considerable ammount of power and also reduces my acceleration times.

I should reduce torque boost at lower revs and simply use a lower gear till I got to about 1500RPM, for acceleration (constant torque region) or 2500 to cruse (constant power region).


----------



## tomofreno (Mar 3, 2009)

http://www.diyelectriccar.com/forums/showpost.php?p=335188&postcount=656
Weighted average speed is around 45 mph, 30 - 40 mph on secondary roads, 50 - 65 mph highways. Charger is low 90's efficiency. Unlike Corbin, I find hills don't change my energy/mile that much as long as there is no significant NET gain in elevation. For example driving up a 1600 ft change in elevation at about 40-45 mph I used 25.6 Ah, coming back down at about the same speed I gained a net 5.5 Ah due to regen, so net 20.1 Ah used for a 12.6 mile round trip. The pack V is lower than the nominal 115V (3.2V/cell) going up, and higher going down while regening, but just using the nominal 115V, that's about 183 Wh/mile, about what I would get at that speed on level ground.



cts_casemod said:


> ... In fact, I think my decision to keep the flywheel/cluch was not the best for city driving as it uses a considerable ammount of energy for acceleration under low gears...


 http://www.diyelectriccar.com/forums/showpost.php?p=346537&postcount=216


----------



## cts_casemod (Aug 23, 2012)

Ziggythewiz said:


> Even without a clutch stop and go takes a lot. I use a disproportionate amount of energy in the first mile at 30 mph. I've read that higher gears take more power, not sure why. In the limited testing I've done I use 20% more in 3rd than 2nd.


 
Thats true, I have experienced the same while tuning the LPG conversion on the older Polo. I thought I had a leak , stop and go uses a considerable ammount of energy, mostly on places where a fast acceleration is required/desirable like busy runabouts and some interceptions on main roads.


I finished converting the VFD so that i can now drive the motor in delta, 2nd gear, instead of 3rd. I now have smilar improvements - 20 to 30% down to 250Wh/m average with the usual 12V accessories - Fan, Lights, etc, during the day I use about the same but I get a lot of stop and go traffic.

Anyway i didnt had this sort of economy with the second gear running in Star, and the car was noticeably slower (20mph max on 2nd gear) so I guess the efficiency improved a bit. Maybe enought to make the next prototype at 650V to have constant power up to 3000RPM keeping the currents low, but I need to do some research on this subject. The controller gives the motor the same voltage per revolution during acceleration and cruize, so this is quite a bif waste of energy if the speed is constant. I need something that can provide extra voltage per revoltution for acceleration and able to throttle it back if the extra power is not required.


----------

