voltamps
Posts: 149
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 11:38 am

SageBrush wrote:
Thu May 13, 2021 8:58 am
If the gear box friction savings is 0.7 Nm, is it correct to say that is 700 joules of energy savings per km traveled ?
The 0.7 Nm is a torque, not quite a force. Energy joules is proportional to a dimensionless radian angular displacement x torque which varies by how much radius the tire has for 1 km of travel.

If we knew it was 0.7 Newton-meters torque savings, then to get total energy saved over 1 kilometer, multiply 0.7 Newton-meters torque times the number of radians of rotation in 1 km. (Assuming you mean 0.7 newton-meters as measured at the wheel.)
Instead of going through a radians per km conversion, :
Easiest way to calculate energy over 1 km (1000 meters) is to divide the 0.7 nm by 0.3 meters tire radius to get 2.33 Newtons force on the road savings.
Then 2.33 Newtons x 1,000 meters = 2,330 joules = 0.00065 kwh saved over a km.
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

voltamps
Posts: 149
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 12:09 pm

knightmb, Does LeafSpy display watts or kilowatts coming out of the battery as you drive?
((( I really need to get LeafSpy. I've had my Leaf for several months now and still have not bothered with it.)))

If LeafSpy (or some other ELM327 bluetoothed OBDII to a phone app or laptop) can display the power (watts or kilowatts) flowing from the battery, then you could take your friends thick-oil Leaf, get a reading, maybe do it a couple of times over a couple routes, maybe three, then change to Valvo ULV, and get the same readings, compare.
Same temperatures, tire pressures same, hoping for no difference in headwinds or tailwinds.
If some wind, then take readings in both directions and average the two directions.
knightmb wrote:
Thu May 13, 2021 11:14 am
I'm about to have a 3rd person help with this. They have a 2015 Leaf, so for the past weeks, we've been recording driving routes, temperatures, efficiency numbers, tire pressure, etc. to help establish a baseline. Then we are going to make the switch from the Nissan Matic S to the ULV (same brand I used) and then do the same recording of numbers for a few weeks to see if any change happens, even if a small, can be recorded. The easy part of having Nissan do some of the data recording via the car link has run into the same issues others have been having with 3G modems, seems to be having connection issues. Going to stick with LeafSpy as much as possible though, easier to work with in spreadsheets. :mrgreen:
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

SageBrush
Forum Supporter
Posts: 6370
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 1:46 pm

OOPS -- let me try again.
First, am I correct in saying that the measurements are at the input shaft ?

Power = torque * 2 * pi * rps


1500 rpm = 25 rps
Then
a torque reduction of 0.7 Nm is a power savings of
0.7*2*pi*15 = 109 watts

Am I getting close ?
Last edited by SageBrush on Thu May 13, 2021 2:35 pm, edited 1 time in total.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

SageBrush
Forum Supporter
Posts: 6370
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 2:09 pm

Back to an earlier post that mentioned ATF heating ...

It takes ~ 2500 joules to heat the ATF one C, and
about 1100 joules of heat are added per second.

So it takes 25/11 = 2.3 seconds of driving to increase the fluid 1C
Call it 27 degrees C a minute

Or 2 - 3 minutes of driving to reach 100 C without heat transfer out of the gear case.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

voltamps
Posts: 149
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 3:02 pm

SageBrush wrote:
Thu May 13, 2021 1:46 pm
First, am I correct in saying that the measurements are at the input shaft ?
By that, do you mean the half-shafts' torque at the wheel connection? It can be wherever you say it is for this example, AFAIK. Isn't this just notional?
I'm not sure what input shaft, maybe you're talking about the motor's output shaft, which is the input shaft to the gearbox.

SageBrush wrote:
Thu May 13, 2021 1:46 pm
Power = torque * 2 * pi * rps
1500 rpm = 25 rps
Then
a torque reduction of 0.7 Nm is a power savings of
0.7*2*pi*25 = 109 watts
Am I getting close ?
Yes, thats it, because there are 2pi radians per revolution so the units work out. And based on newtons, seconds, meters, watts, joules being consistent units to calculate energy and power.

I just loaded LeafSpy Lite (free) and it works on my BAFX brand ELM327 bluetooth thingie on the OBDII port.

Did you get the 0.7 Nm torque delta difference from the motor's output shaft readout in a better version of LeafSpy?

My "lite" version only shows me battery module voltages as far as I can tell. Guess its worth getting the full version, maybe even the Pro one, to see if it gives battery power output in kW or Watts. The kW on the dashboard would be OK, but would rather have a number to get a delta difference. This would be good to do if changing tires and we wondered if the new tires have better or worse rolling resistance.
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

SageBrush
Forum Supporter
Posts: 6370
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 3:11 pm

voltamps wrote:
Thu May 13, 2021 3:02 pm
Did you get the 0.7 Nm torque delta difference from the motor's output shaft readout in a better version of LeafSpy?
I pulled it from the article you posted earlier (with a little rounding and averaging.)

To recap:
About a 10% reduction in power use in the gearbox,
The gearbox is ~ 10% of motive power **
So overall, the thinner oil results in ~ 1% additional range.

Yes, input shaft to the gearbox.


**
That actually surprises me. IIRC the Prius gear set is under 5%
You might find this article on the Prius drivetrain interesting
https://www.osti.gov/servlets/purl/921783
See page 33 of the pdf, page 25 on the printed page
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

voltamps
Posts: 149
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 4:00 pm

SageBrush wrote:
Thu May 13, 2021 3:11 pm
I pulled it from the article you posted earlier (with a little rounding and averaging.)
OK, I see the 0.7 Nm off one of the graphs in there. I was mostly looking at the percent efficiency vs. torque input graph next to it, but either works.
That 0.7 Nm difference (loss) from the thick vs. thin fluids is "spin loss", lightly loaded in a double planetary gearset auto tranny, although it might be our simpler gearbox could have 109 watts of dissipation, more likely less, not sure here.
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

knightmb
Posts: 970
Joined: Mon Jan 12, 2015 7:41 pm
Delivery Date: 26 Feb 2021
Leaf Number: 306291
Location: Franklin, TN

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 4:26 pm

voltamps wrote:
Thu May 13, 2021 12:09 pm
knightmb, Does LeafSpy display watts or kilowatts coming out of the battery as you drive?
((( I really need to get LeafSpy. I've had my Leaf for several months now and still have not bothered with it.)))
I think mine was set for watts (vs kilowatts), but I think pressing the number can change it between many different units.
2020 Leaf SL Plus - (Manufacture Date March 2020)
2013 Leaf SV (8 faithful years of service before trade in at 75,679 miles)
Timekoin - The World's Most Energy Efficient Encrypted Digital Currency

voltamps
Posts: 149
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 5:38 pm

knightmb wrote:
Thu May 13, 2021 4:26 pm
I think mine was set for watts (vs kilowatts)
OK, I was wondering if LeafSpy would even have Power (watts) at all. It does, which makes perfect sense! My el cheapo free LeafSpy Lite doesn't. .........The left side dashboard display (on my 2020 at least) does have those semi-circular power bars that I could take a picture of with my phone when I drive past a known landmark on a road at a certain speed.

With cruise control on, I'll try to take a snapshot of the power-bars on the dash, or from LeafSpy Pro.
Then repeat to see if I can get the same picture.

What would really be cool is if we could command a fixed power output, and then just look to see what MPH speed that gives us.
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

knightmb
Posts: 970
Joined: Mon Jan 12, 2015 7:41 pm
Delivery Date: 26 Feb 2021
Leaf Number: 306291
Location: Franklin, TN

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 6:17 pm

I was looking at the app store entry for LeafSpy, the problem is the screen shots are just too small a resolution, you can't see it all the stuff it shows. I can run mine and take a few screenshots to better show what LeafSpy Pro can show for readings. Years ago, I just started doing some random presses to see how many different readings I could switch it around too.... :lol:

Edit: Added some screenshots... you can customize the screen data so you can tell mine is heavily customized :lol:

High Throttle...
Image

High Regen...
Image

Driving Data Logs...
Image
Image
2020 Leaf SL Plus - (Manufacture Date March 2020)
2013 Leaf SV (8 faithful years of service before trade in at 75,679 miles)
Timekoin - The World's Most Energy Efficient Encrypted Digital Currency

Return to “Tips & Tricks”