Performance - Max Grade Climbing

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garygid

garygid

Well-known member
Joined
Apr 21, 2010
Messages
12,469
Location
Laguna Hills, Orange Co, CA
With the LEAF over 3300 pounds,
the maximum torque listed at 209 foot-pounds,
and the wheel & tire radius at about 1 foot:

209 ft-lbs / 1 foot = 209 lbs maximum "push".
209 lbs / 3300 lbs = about 0.063, or just a little over a 6% grade.

So, is the LEAF's MAXIMUM constant-speed grade-climbing
ability something under a 7% grade?

Others talk about going up "mountains" or hills with an 8% grade.

What am I missing?
Thanks, Gary
 
I believe that is the motor spec, there is the torque multiplication of the transfer case. The LEAF can climb very steep grades I can assure you, and any hill in SF at very high speed and those make 8% grades look easy. IF the motor were only connected to the wheels there would be an issue.
 
garygid said:
With the LEAF over 3300 pounds,
the maximum torque listed at 209 foot-pounds,
and the wheel & tire radius at about 1 foot:

209 ft-lbs / 1 foot = 209 lbs maximum "push".
209 lbs / 3300 lbs = about 0.063, or just a little over a 6% grade.

So, is the LEAF's MAXIMUM constant-speed grade-climbing
ability something under a 7% grade?

Others talk about going up "mountains" or hills with an 8% grade.

What am I missing?
Thanks, Gary
Click to expand...
Variables:
Passengers (load)
Wind speed/direction
Length of trip/state of charge
 
We were playing around with how fast the LEAF would go up a hill near our house (and how much regen down the hill).

With 2 1/2 people, ISA plus 5C at near sea level, max speed up the hill was 82.

Max regen down the hill was about 15kw at 45mph, and about 22kw at 60mph, both in ECO mode. Obviously, hitting the brake pedal can max out either to 30kw.

So, towing your LEAF with a motor home for about an hour at 60mph will fully charge the battery.
 
That assumes that it would continue regening at that level for the entire hour, which I doubt. Likely it would taper off quickly to a much lower value... Regardless, it is an inefficient (and likely unsafe) way to charge.

TonyWilliams said:
So, towing your LEAF with a motor home for about an hour at 60mph will fully charge the battery.
Click to expand...
 
I live in a very hilly area of Seattle, 98199. Dravus street is very steep grade and my Leaf climbs it like a rocket. I have to lift the petal to not catch air at the cross streets. Starting from a dead stop on the hill is easy and smooth. This is the route I take when giving demo rides to friends and neighbors. They are always amazed and realize that this isn't a golf cart. They know what their ICE car does on the hills, all the down shifting, noise and rotten egg exhaust smell from the catalytic converters and appreciate the difference. The Leaf is awesome in this urban environment! :D :D :D
 
mogur said:
That assumes that it would continue regening at that level for the entire hour, which I doubt. Regardless, it is an inefficient (and likely unsafe) way to charge.



Neither of us know whether it will continue for an hour or not. It's not likely that it would matter if it was an hour, or 90 minutes. It is fast, I think we can agree.

The efficiency is TIME. If I'm towing the LEAF anyway, and would like to use it at my next RV destination 90 minutes away, it is absolutely efficient.

Please expand on the "unsafe" part. If it's unsafe for regen, then I need to sell my car now.
Click to expand...
 
Oh, gear ratio, of course, yes! THANKS

The 8 to 1 gear ratio means 8 times the torque at the wheels.

So about 200 x 8 = 1600 foot-pounds at the wheels, perhaps enough for a 50% grade (about 26%), if the tires do not slip. A 100% grade is a 45º incline, VERY STEEP, that many would usually have trouble walking up, or even standing on.

Thanks, it's my brain losing connections, it seems. :lol:
Hey, what's so funny?
I don't know, ... and who are you anyway?

Edited to correct grade errors.
 
I have been taking some our steepest grades here for fun. No idea on grades, but it makes some hills in downtown seattle look flat.

It feels like my V6, if not better taking in account the lack of transmission downshift. If anything, I could probably beat anything off the line at a stop light.
 
The car must be in ECO mode for this to work which means it is on and "in gear". Leaving a vehicle like this is inherently dangerous unless you plan to have someone sitting in the drivers seat the entire time to monitor it and intervene if necessary... It may also illegal under some vehicle codes...

TonyWilliams said:
Please expand on the "unsafe" part. If it's unsafe for regen, then I need to sell my car now.
Click to expand...
 
Towing it behind an RV in Eco mode should work, but perhaps try it at first at 45mph or something like that.. make sure nothing overheats. How do you plan to attach it to the RV?.. the regen will put an unusual load on the towing attachment so dont get killed doing this. It will literally sap about 20hp out of the RVs engine so dont overheat it either.

Apparently regen is disabled when the battery is nearly full, so you probably wont get it to 100%. You could also attach the 120V EVSE and tow the Leaf on a dolly, and run the genset on your RV... or a 240V modified EVSE

Dont tell Nissan since you will probably void the warranty :)
 
That 22KW you saw at 60 MPH would be just about 30 HP. And if they're telling us about "into the battery" then you have to add some more for the generator inefficiency. So your RV might go from 12 MPG to 9...the thing you want to know is "Will I make to the campground?" The good news is, when the motor home starts speeding up on it own, then you know the LEAF is done charging :D
 
Herm said:
Towing it behind an RV in Eco mode should work, but perhaps try it at first at 45mph or something like that.. make sure nothing overheats. How do you plan to attach it to the RV?.. the regen will put an unusual load on the towing attachment so dont get killed doing this. It will literally sap about 20hp out of the RVs engine so dont overheat it either.

Apparently regen is disabled when the battery is nearly full, so you probably wont get it to 100%. You could also attach the 120V EVSE and tow the Leaf on a dolly, and run the genset on your RV... or a 240V modified EVSE
Click to expand...
Either way you will be using a huge amount of gasoline or diesel relative to the miles you add to the LEAF. Far better to charge at home before you leave, and charge overnight in an RV park each night you are away.

Ray
 
But it would make a pretty good Jake Break for those downhill runs! :lol:

planet4ever said:
Herm said:
Towing it behind an RV in Eco mode should work, but perhaps try it at first at 45mph or something like that.. make sure nothing overheats. How do you plan to attach it to the RV?.. the regen will put an unusual load on the towing attachment so dont get killed doing this. It will literally sap about 30hp out of the RVs engine so dont overheat it either.

Apparently regen is disabled when the battery is nearly full, so you probably wont get it to 100%. You could also attach the 120V EVSE and tow the Leaf on a dolly, and run the genset on your RV... or a 240V modified EVSE
Click to expand...
Either way you will be using a huge amount of gasoline or diesel relative to the miles you add to the LEAF. Far better to charge at home before you leave, and charge overnight in an RV park each night you are away.

Ray
Click to expand...
 
garygid said:
So about 200 x 8 = 1600 foot-pounds at the wheels, almost enough for a 50% grade (a 45º incline, VERY STEEP, that you would usually have trouble walking up, or even standing on), if only the tires would "stick" and not slide.
Click to expand...

A 45º incline is a 100% grade. 100' out and 100' rise is 100%.

50% grade is 100' out and 50' rise. I will leave the trig angle to your slide rule. ;)
 
If I'm not mistaken, I believe that the towing recommendations in the owner's manual advise against having the front wheels on the ground. If you're towing it behind an RV, it may be better to get one of those front wheel towing dollies.
 

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