voltamps
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Delivery Date: 14 Dec 2020

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 7:43 am

I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.
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
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Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 8:58 am

voltamps wrote:
Thu May 13, 2021 7:43 am
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile
Starting from 1% savings -- sure.

But I want to be stubborn and think about this *my* way ...
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 ?
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

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 9:15 am

voltamps wrote:
Thu May 13, 2021 7:43 am
I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.
Thanks for posting that, it puts everything into perspective. Is there any additional energy saving when cooling the gear oil is mixed in? I mean, all of them (oils) are designed to provide low viscosity at high(er) temperatures. If you have something that is cooling the gear oil to keep it at a certain temperature versus the heat generated by the friction within the system (gears, oil, etc.)?

If anyone has every noticed that on a warm day, you plug in your Leaf to charge. After a while, you hear the cooling pump running. If the coolant is warm enough, you can even hear the fans kick on. All of that uses energy, not sure how much, haven't measured.

Now, if on a warm day. Say you have a nice stretch of highway to just dump the throttle and go 0 to 100 mph non-stop. During that intense acceleration (for a Leaf anyway), if you listen carefully, during some part of that acceleration, you will hear the radiator fans kicks in, loud at high speed. I had to tape a cheap phone to the inside of my Leaf to find out :mrgreen: because during high power usage, it always sounded like another system of motors was kicking in, now I know what it was. So it is possible to really heat up the motor (and gear box too I would guess).

It would seem that the gear box oil, using ULV, as many others have said, in theory, doesn't really gain much (1% extra range by itself). That's why I have a theory that, looked at alone, the ULV isn't producing huge range gains, very small as you can demonstrate by the math. But... it might be part of an avalanche effect within another system of the Leaf (cooling system) that uses a lot more power and thus keeps the temperature just low enough that this more power hungry system doesn't have to switch on (as much) and that's where the extra range savings is coming from. Both in hotter climates because of cooling and cold climates because of heat needed to reach a good viscosity for the oil to function.
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

SageBrush
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Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 9:32 am

knightmb wrote:
Thu May 13, 2021 9:15 am
It would seem that the gear box oil, using ULV, as many others have said, in theory, doesn't really gain much (1% extra range by itself). That's why I have a theory that, looked at alone, the ULV isn't producing huge range gains, very small as you can demonstrate by the math. But... it might be part of an avalanche effect within another system of the Leaf (cooling system) that uses a lot more power and thus keeps the temperature just low enough that this more power hungry system doesn't have to switch on (as much) and that's where the extra range savings is coming from. Both in hotter climates because of cooling and cold climates because of heat needed to reach a good viscosity for the oil to function.
There is an interesting trade-off going on here since viscosity drops as its temperature increases and the thicker oil warms up quicker.

The specific mass of oil is ~ 0.8 grams per liter, so perhaps 0.7 (?) for these thin oils.
The specific heat is ~ 2,000 joules per Kg*C. So it sounds like LEAF like ranges are not going to heat up the oil to temperatures that require active cooling but a thicker oil will heat up quicker.
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

lorenfb
Posts: 2511
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 10:14 am

voltamps wrote:
Thu May 13, 2021 7:43 am
I get 3,9 miles per kwh on my '20 SV, so 1/3.9 = 0.256 kwh/mile === 256 wh/mile typically.
Without any air resistance (air drag), that figure would probably be around 7 miles per kwh, so let's use 7.
So 1/7 = 143 wh/mile
Energy savings per mile would be 1% of 143 wh/mile ==== 1.43 wh/mile === 0.00143 kwh/mile

Or you could just say I'd get 150 miles from my 40 kwh battery using Nissan Matic S, and that increases to 151 miles on Valvoline ULV thinner oil. Much of the Road Load (power required to drive on level ground with no headwind or tailwind) is from basic air drag, so something around 1 mile advantage in range is the net effect, depending on driving style, city or hiway.
Which makes this thread laughable!
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

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 10:20 am

Owning an EV, or any car really, makes me think back to Physics. I'm a Halliday-Resnick 2nd Edition person myself, early 1980's requirements for engineering school. That textbook has been improved since, and I need to check out the continuous improvements made by Walker after 1990. Cool subject! The better you know that book, the better an engineer you are, no kidding, it is the foundation.
Image
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
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Re: Reduction Gear Oil Change - Benefits for Range

Thu May 13, 2021 10:28 am

voltamps wrote:
Thu May 13, 2021 10:20 am
I'm a Halliday-Resnick 2nd Edition person myself, [/img]
I have the green edition.
Although I have to say -- you learned more from Resnick than I.
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 10:55 am

knightmb wrote:
Thu May 13, 2021 9:15 am
Is there any additional energy saving when cooling the gear oil is mixed in?
Cooling the gears would make the oil stay thicker (more viscosity), and thicker oil loses even more energy. I say don't cool the oil too much since you actually want it to get as thin as possible, within limits.
knightmb wrote:
Thu May 13, 2021 9:15 am
....the fans kick on. All of that uses energy, not sure how much, haven't measured.
Fans are wasting energy. Those fans are getting rid of the heat during charging. It's not much lost energy. Certainly losses though. Gone.

On that same note, I was once curious as to how much heat losses you get charging & discharging an Li-Ion battery. I think I found you only lose around 2% lost to waste heat, depending on the amps going in or out, but usually not much.
knightmb wrote:
Thu May 13, 2021 9:15 am
..... avalanche effect within another system of the Leaf (cooling system) that uses a lot more power....
That's true to some extent. Think about it from the viewpoint of how much power (watts) has to flow on the wires feeding the motor. If the gearbox is more efficient, less watts are needed on those wires, less waste heat is generated. A small amount less. Same goes for better lower resistance tires, it results in the need for less watts on those wires & less heat too.

In fact, maybe the best way to look at all this is to use some hard facts we have. The Road Load, which has been measured on Leafs many times. Road Load includes the gearbox internal frictional drag, and all the dissipative energy losses up into the motor's internal windage losses.

Therefore, Road Load is great to tell us how many Watts must flow out of the battery itself !!!

Road Load at 60 MPH is 489 Newtons.
So that is 26.8 meters/second x 489 N = 13.1 kW power being drawn out of the battery at 60 mph.
Road Load from a 2013 Leaf (similar in a 2020 Leaf) from https://inldigitallibrary.inl.gov/sites ... 737951.pdf page 5.

Routing 13.1 kW power through the gearbox, 1% of that would be 0.131 kW savings using low visc oil. Like burning a 100 watt light bulb waste at 60 mph.
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 11:02 am

lorenfb wrote:
Thu May 13, 2021 10:14 am
Which makes this thread laughable!
My approximations don't quite cut it, that's true. That part is laughable. There is nothing like simply trying it on the road like what knightmb & estomax are doing.

The engineering paper that showed about a 1% loss from using thicker oil kind of nails the issue, done in a real transmission. The challenge for physics modelers is to include & know about enough things to simulate it right.

.......knightmb had a good point about there being some (small??) cascading savings effect, when your battery has to provide less watts flowing out to overcome all the losses in the Road Load. Anything saved is less you have to cool with pumps and fans.
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 11:14 am

voltamps wrote:
Thu May 13, 2021 11:02 am
My approximations don't quite cut it, that's true. That part is laughable. There is nothing like simply trying it on the road like what knightmb & estomax are doing.
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 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

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