JoeS
Site Moderator
Posts: 3065
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Regen vs Neutral and speed for max range

Thu May 04, 2017 8:39 am

Aerowhatt, thank you for the excellent and very logical suggestions, especially the one driving in Eco which reduces the pedal sensitivity. I'm pretty tied up for the next couple of days but will attempt to do this every time I go to town.
EVs: 2 Wht/Blu SE Prem., '13 Tesla S85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

JoeS
Site Moderator
Posts: 3065
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Regen vs Neutral and speed for max range

Fri May 05, 2017 10:49 am

Brief update: using SoC over this short stretch doesn't work, as both CaniOn and EVBatMon only show a 0.5% resolution, which doesn't change over the course of this downhill, using either technique.

Will keep trying to see if Wh/km is doable, as controlling the amount of energy going into the car during acceleration is difficult/unmeasurable?, as is keeping a steady foot on the accelerator.

Science Saved Me A Ticket. Good thing I was going slow doing this testing, as yesterday there was a barely-visible Sheriff standing in the shadows with a handheld laser gun point up that final downstretch...
EVs: 2 Wht/Blu SE Prem., '13 Tesla S85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Aerowhatt
Posts: 306
Joined: Wed Jan 28, 2015 1:52 pm
Location: Albuquerque NM

Re: Regen vs Neutral and speed for max range

Fri May 05, 2017 1:59 pm

JoeS wrote:Brief update: using SoC over this short stretch doesn't work, as both CaniOn and EVBatMon only show a 0.5% resolution, which doesn't change over the course of this downhill, using either technique.

Will keep trying to see if Wh/km is doable, as controlling the amount of energy going into the car during acceleration is difficult/unmeasurable?, as is keeping a steady foot on the accelerator.

Science Saved Me A Ticket. Good thing I was going slow doing this testing, as yesterday there was a barely-visible Sheriff standing in the shadows with a handheld laser gun point up that final downstretch...


I was afraid of that. It's a pretty short road at only 1.3 miles. Wh/km should be able to show up a difference even on a short hop. That's what's nice about my "mostly" descent, it's 27 to 34 miles long depending on the chosen starting point. Sections that I look hard at because of their consistency of conditions are 5 miles or more each. Problem is I can't test it at 35 mph. The speed limits for the most part are 45 to 65 mph. Drivers around here tend to add at least 5 mph to that. Just not a safe option to go slower!

I did a little refresher on aerodynamic drag while waiting in stopped traffic today. Comparing 7,500 ft elevation to sea level. Air density
is a nice round 80% of sea level at 7,500ft (the averaged altitude of my journey). Since air density is a single multiplier in the drag equation it gets simple. Basically, given the same velocity one would be fighting 80% of the resistance that they would be at sea level.

Aerowhatt
2014 cool silver ES, acquired new 4/2015
2014 Labrador Black Pearl ES, acquired new 3/2016

JoeS
Site Moderator
Posts: 3065
Joined: Thu Dec 15, 2011 5:47 am
Location: Los Altos Hills, California

Re: Regen vs Neutral and speed for max range

Thu May 18, 2017 9:25 pm

Aerowhatt, thanks for doing the drag comparison. Hey, the only reason for this whole discussion is the aerodynamic drag effect!

Well, I've been totally unsuccessful in trying to get any meaningful data by trying to keep the accelerator in a constant position and a constant speed. The combination of curvy and undulating road, short distance, and slow speed makes it not doable, IMO. On this stretch, it is soooo much easier to just kick the car into Neutral and not worry about it. For maximizing range, this low speed test doesn't address the comparison we're trying for, anyway. Neutral gives me a steady-state current draw of 1.3A (correction, I had written 1.8A) at around 50%SoC.

During my recent Tesla trip I played with Neutral as well as holding the speed down on steep slopes and regenning like crazy. The problem with Neutral and the Tesla is that its Cd is so low that the thing just keeps going faster and faster...

Without a controlled test on the same stretch of road on which one has the ability to go both at 70 mph and 35 mph to do comparative measurements, we're still at an impasse. An early Sunday morning on the Interstate near me might work at 35mph for a few minutes...
EVs: 2 Wht/Blu SE Prem., '13 Tesla S85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

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