Strategic Driving for Efficiency, 2018 e-golf model

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Joined
Oct 5, 2018
Messages
10
Hello all,

I thought I'd share a bit of my driving strategy that has worked to provide a high level of efficiency/lower battery consumption.

I'm between 12-500ft above sea level during my commute, mostly flat roads with some hills, but nothing too steep for too long. Air temperature is usually between 45f and 75f. Generally no adverse weather conditions, with only light winds. I keep the car in "eco" mode.

Here's the main point of strategy: I drive with the "Economy" data in the instrument cluster. I try to accelerate quickly enough to get inertia to help carry the car out of the 0.5-1.9 mi/kWh range. The idea here is that keeping at 2-4.5 mi/kWh of consumption is where there's enough power to move the car quickly, without staying in that high-torque/high-drain area of initial acceleration.

The second point of strategy: getting off the accelerator pedal as-much-as-possible! I try to bump the car up to speed, and then let it roll. Sometimes it's called "gliding" and sometimes it's called "coasting". Whatever you want to call it, keeping off the accel. pedal is key to efficiency!

The third point of strategy: I don't use cruise control! You shouldn't either! I use regeneration Level 1 to trim the speed on downhill sections of road. I use B mode when approaching signal lights. Other than that, keep the energy consumption under your own control, and don't get lazy.

Using these three methods, I was able to travel 44.5 miles on the highway and only consumed 22 miles of energy. That's because for 50% of driving I had my foot off the accelerator and let the car glide. The rest of acceleration was done such that I never dipped below 2 mi/kWh. I regenerated sparingly, kept climate control off, and did not have music or the infotainment screen activated.

This style of driving is very pro-active and not for everybody. But splitting consumption in half is worth it! I will be doing a longer range test soon, and will post an update. :)
 
tetrahydro said:
Hello all,

I thought I'd share a bit of my driving strategy that has worked to provide a high level of efficiency/lower battery consumption.

I'm between 12-500ft above sea level during my commute, mostly flat roads with some hills, but nothing too steep for too long. Air temperature is usually between 45f and 75f. Generally no adverse weather conditions, with only light winds. I keep the car in "eco" mode.

Here's the main point of strategy: I drive with the "Economy" data in the instrument cluster. I try to accelerate quickly enough to get inertia to help carry the car out of the 0.5-1.9 mi/kWh range. The idea here is that keeping at 2-4.5 mi/kWh of consumption is where there's enough power to move the car quickly, without staying in that high-torque/high-drain area of initial acceleration.

The second point of strategy: getting off the accelerator pedal as-much-as-possible! I try to bump the car up to speed, and then let it roll. Sometimes it's called "gliding" and sometimes it's called "coasting". Whatever you want to call it, keeping off the accel. pedal is key to efficiency!

The third point of strategy: I don't use cruise control! You shouldn't either! I use regeneration Level 1 to trim the speed on downhill sections of road. I use B mode when approaching signal lights. Other than that, keep the energy consumption under your own control, and don't get lazy.

Using these three methods, I was able to travel 44.5 miles on the highway and only consumed 22 miles of energy. That's because for 50% of driving I had my foot off the accelerator and let the car glide. The rest of acceleration was done such that I never dipped below 2 mi/kWh. I regenerated sparingly, kept climate control off, and did not have music or the infotainment screen activated.

This style of driving is very pro-active and not for everybody. But splitting consumption in half is worth it! I will be doing a longer range test soon, and will post an update. :)

Nice, I'm averaging, long term, about 6.1 to 6.3 miles traveled, per kWh, in my infotainment center. Higher in summer, lower in winter. I use D and D1 or D2. Using "B" charges the battery hard and fast, not good for the battery, and it wastes energy powering the brake lights, as soon as you back even slightly out of the throttle. It makes the person behind you think you're a tailgating moron, with all the brake light on and off usage. YMMV, that's how I do it, it works for me, and me only. But I have a lot of patience, when driving.
 
JoulesThief said:
Nice, I'm averaging, long term, about 6.1 to 6.3 miles traveled, per kWh, in my infotainment center. Higher in summer, lower in winter. I use D and D1 or D2. Using "B" charges the battery hard and fast, not good for the battery, and it wastes energy powering the brake lights, as soon as you back even slightly out of the throttle. It makes the person behind you think you're a tailgating moron, with all the brake light on and off usage. YMMV, that's how I do it, it works for me, and me only. But I have a lot of patience, when driving.

Wow, that's interesting about B mode, that it charges the battery hard and fast which is not good for the battery. I will keep that in mind... What's your experience with D3? From what I can tell driving at night, it doesn't activate the break lights when I let off the accelerator, but it still regenerates pretty strong. Is that also a concern for long-term battery health?

Obviously I want my battery to last a long time. At least 7-10 years.
 
We don't know if using B mode charges the battery "hard and fast". C rate is what determines "hard and fast". Since VW doesn't show us what C rate is delivered using B mode, we can't accurately comment on battery damage. I can tell you when I charge my 2017 fully ( a very rare occurrence since I usually charge to 80% for battery longevity), using B mode does not give the same level of regeneration as when charging to 80%. If the VW software is written well, and based on this observation, I believe it is written well, then it is my opinion that using B mode will do no more damage than using any other way of slowing the car. Don't forget, even if you stomp on the brakes in D mode, regen is used first and then the friction brakes kick in - you can't avoid using regen in the e-Golf and that is part of the reason why it is very efficient. Sure, coasting is best. Unless you can view the computer code or record regen power in real time using an OBD dongle/software, it is impossible to asses regen vs C rate issue based on the power needle and all we can express are our hunches and opinions. My brake lights are LED so they use negligible power.

I just drove 90 miles from Monterey, CA to the San Jose, CA area on highway 101 (mostly flat, but there are hills here and there), with an external temperature of around 60 F, I set the cruise at 62 mph (speed limit is usually 65 mph), stayed in the right lane, car was in ECO mode with all heating and cooling turned off, just myself and some luggage, and I averaged 55 mph with 4.8 miles/kWh efficiency. I occasionally cracked the front and rear windows to get fresh air. It rained for part of the trip, too. I had the car in either B mode (for quick slowing as needed) or D1 mode. I preheated the car prior to leaving.
 
I also don’t think the regen approaches anywhere near the 7.2 kW that the eGolf can draw off the grid.
 
I've driven down the Camarillo grade at 55- 60 mph on a 60F degree day in D3, and about 2/3 of the way down the grade, on 2/3 full charge, the car wasn't slowing down due to regen, it was slacking off. Battery was getting warm from recharging and reducing the recharge rate.

I've noticed the same coming down highway 2 on Angeles crest highway. I don't know how else to explain it?
 
As the eGolf doesn't have a battery temperature meter (like the Leaf does), I don't know how you would know the battery is 1. getting too warm, and 2. how it's affecting regen. I come across numerous situations where I can feel the friction brakes kicking in but I'm not getting maximum regen despite my battery being less than full.

But assuming that you are correct, then the car is self-regulating its own battery temperature, and preventing it from overheating, so driving in "B" isn't going to prematurely kill the battery.

I have driven the Angeles Crest in my eGolf and "B" actually scrubs off too much speed. Same with the southbound 2 Freeway (which is fairly steep) coming down from the La Cañada area.
 
This summer, I drove down a mountain from 5200 feet to about 500 feet above sea level, in a variety of regen modes to modulate speed. I started at the top of the mountain at 90% SOC. When I got to the bottom of the mountain, I had approximately 92% to 95% SOC. There were a lot of switchbacks and even elevation gains at times, with speeds around 40 to 50 mph all the way down, and I three people in the car, with luggage. I never saw any change in the regen power. This was with weather in the 70s and 80s. I never saw any change in the battery power gauge. When I got the the bottom of the mountain, I drove in B mode and it functioned as normal with heavy regen.
 
I though I saw in these forums it was suspected that regen can pull up to the same 39kw that DC charging can take. It certainly can take more that 7.2. I’ve been able to add 1kw in less than 5 min going downhill.

My Pacifica shows in real time how hard it’s regenerating, up to 85kw! Sure wish the e Golf have more data.
 
My tip is.... remember Regen is not really your friend. Any energy you use and remove from the battery, will lose a percentage if you Regen it back into the battery. There will be inefficiency losses. Just recharging a battery takes about 110% of what you took out.
I can’t prove it, but I expect that these Regen losses are higher than the losses due to air friction,wheel bearings and tires.
So gliding will result in lower losses.

I would like to know the speed where air friction causes gliding losses to equal that of Regen losses. Or, how fast can roll down that hill before it would have saved more energy regening.
I do try (traffic permitting) to hit the top of a hill as slow as possible. Then gliding down the other side will result in max energy being saved as increased inertia and minimum air friction losses.

I’ve been EVing for almost 4 years and never expected this level of fun just driving.

Barry
 
BarryMW said:
My tip is.... remember Regen is not really your friend. Any energy you use and remove from the battery, will lose a percentage if you Regen it back into the battery. There will be inefficiency losses. Just recharging a battery takes about 110% of what you took out.
I can’t prove it, but I expect that these Regen losses are higher than the losses due to air friction,wheel bearings and tires.
So gliding will result in lower losses.

I would like to know the speed where air friction causes gliding losses to equal that of Regen losses. Or, how fast can roll down that hill before it would have saved more energy regening.
I do try (traffic permitting) to hit the top of a hill as slow as possible. Then gliding down the other side will result in max energy being saved as increased inertia and minimum air friction losses.

I’ve been EVing for almost 4 years and never expected this level of fun just driving.

Barry

Good advice, and interesting thoughts deeper than my brain can ponder.

In city driving in Santa Cruz we almost never use regen except what can't be controlled (the brake pedal). On the rare occasions we drive over the hill to the San Jose area regen is awesome coming down 17. I use the 3 modes (but never B) coming down the hill and seldom touch the brakes, hardly any "throttle" as well. There is a noticeable rise on the charge gauge from the summit to the bottom of the hill. Driving the car this way results in more range on our over the hill trips than we got before trying this technique, and it is fun and engaging kinda like a manual trans.

That said, when driving a manual ICE car I do not normally use the driveline instead of brakes except when descending long grades. I was taught decades ago by my Porsche mechanic friend that brakes are way less expensive to maintain than drivelines and you also are smoother. (Smoother = faster too.)
 
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