Electric car efficiencies

[TheEnemy]

Using my Jeep as a comparison to those motors torque values because I know the gears on it.

Engine 230ftlbs at 1800rpm,
First gear 3.3:1
T-case (Low range) 2.6:1
Axle 3.54:1

Gives me 6,985 ftlbs to the axle shafts

*0.8 to account for drive line losses = 5588ftlbs

Now granted the only times I am anywhere near that torque rating is when pulling someone, or bound up in the rocks, or when I have entered it into the mud bogs which is <1% of the time

5th gear .75:1
Tcase (high range) 1:1
Axle 3.54:1

1600rpm at 75mph (at full throttle) est 210 ftlbs from the engine

=446ftlbs

At 75mph I'm making 210*1600/5252 = 64hp (yes its a cinderblock on wheels)

Converting to kwh for a 150mile 2 hour trip I would need about 100kwh. (only a couple times a year with this thing)

Its a good thing this is my weekend beater.

[TheEnemy]

If I used those motors in the Jeep (yes I have been thinking about electrifying it) I would still want a gearbox T-case only maybe.

[drmiller100]

Originally Posted by TheEnemy

Using my Jeep as a comparison to those motors torque values because I know the gears on it.

*0.8 to account for drive line losses = 5588ftlbs

.

rev the engine, and drop the clutch, and your torque at the wheels will be even higher.

[NeilBlanchard]

The FVT motors and the YASA motors are direct drive, and that torque is at the output shafts. On the YASA motor torque / efficiency graph, it shows it has that 750Nm (533ft/lbs) is available as low as ~100RPM. That would mangle most gears, and gears that are strong enough would lose power through friction. Heck, the YASA has peak efficiency of 94-95% without any gears!

[Old Mechanic]

My Maxima differential has been handling more than that for 13 years and 144,000 miles Neil, with the fluid changed once, long after your batteries have died and you need to spend what my car cost new to replace them. About 6000 gallons of gas.

regards
Mech

[Old Mechanic]

Va Tech calculated my in wheel drive produced 380 pounds feet of torque at 0 RPM.

Per wheel at 99% efficiency at 0 RPM. Your motor can't touch that or regenerate any significant amount of energy.

regards
Mech

[Old Mechanic]

Nissan addresses Leaf battery life, replacement costs

regards
Mech

[Old Mechanic]

15% loss from your meter to the motor, at 100% motor efficiency your are never going to get better than 85%. Lets say the average, not peak, efficiency is 90%. Now you are at 90X85=76.5%
Also no decent regeneration efficiency in any direct drive setup so you only get back say 30% from regeneration, probably less since you can't recover several hundred horsepower seconds of energy in 22 revolutions of the wheels, especially with 2 wheel drive.

regards
Mech

[Ladogaboy]

Originally Posted by Old Mechanic

Nissan addresses Leaf battery life, replacement costs

regards
Mech

Man, I understand that they are trying to assuage fears about the battery life, but this is just a basic marketing tactic. "Battery replacements starting in the hundreds of dollars." I wonder how many modules would need to be replaced before the thousands start adding up....

[Old Mechanic]

One will be here soon.

https://www.iaai.com/Auctions/Auctio...eDateView.aspx

regards
Mech