Hypermiling The Electric Drive

[steveyfrac 73]

This morning I set out on a mission. A mission to use as little of my battery pack as possible.

It was cool enough that A/C wasn't an issue. I ran with the HVAC on, but set as cool as possible, and the A/C off. Acceleration was almost entirely kept under 25% power. Lots of coasting. Lots of crawling up large hills at 30 km/hr in an attempt to minimize peak current draw, and wring the most out of the battery pack. (This is because of Peukert's law )

The net result:

My energy consumption was 13.3 kWh / 100 km. I ended up driving 27 km using 15% of available battery. This would put my theoretical range at 180 km ish, assuming the SOC meter is linear, which I suspect it is not.

How do you hypermile your Electric? What kind of range / energy consumption have you managed?

[Huronlad 186]

If my math is correct, consumption at 13.3kW/100km and 17.6kW battery capacity works out to 132km total range.

[steveyfrac 73]

If my math is correct, consumption at 13.3kW/100km and 17.6kW battery capacity works out to 132km total range.

Indeed. But the problem is that the 17.6 kWh rating is based on a 1C discharge rate, and the capacity actually climbs when you drain it more slowly. I've driven more than 130 km in a day without driving this hardcore eco.--Steve

[Huronlad 186]

Rate of discharge is not going to gain you 36% extra capacity.

[steveyfrac 73]

Rate of discharge is not going to gain you 36% extra capacity.

Here's my SOC readout from this morning:Either my state of charge meter is non-linear, the kWh rating of the battery is wrong, or the energy consumption meter is wrong. I'm guessing it's some combination of the first two. In any case, I'm pretty confident I'd be able to hit 150 km today, if I continued driving like I did this morning based on past experience.In the past I've typically used 20% to drive my first 27 km to work, and still gone on to drive another 80-90 km on the same charge, for 110 - 120 km on a charge without going below 20% battery. Today, I did 25% better than average on my drive in, in terms of both energy consumption, and state of charge.What do you think? Or are you just flat out calling me a liar here?--Steve

[Huronlad 186]

By the math, your consumption will have to drop down to 11.7kW/100km to see a range of 150km.There is a thread on CsC or sCOA documenting trip consumption but I can not find it, that would give something for comparison.

[steveyfrac 73]

By the math, your consumption will have to drop down to 11.7kW/100km to see a range of 150km.There is a thread on CsC or sCOA documenting trip consumption but I can not find it, that would give something for comparison.

Your math assumes the Peukert effect doesn't exist, and also contradicts my experimental data. It also ignore a half dozen other issues such as intermittent vs continuous discharge, battery temperature, etc..I've driven 110 km on a charge, despite energy consumption in the 16.x kWh / 100km range for my round trip, and still had 25% battery left. By your math this isn't possible.My car also tells me I have 110 km of range when full, despite using an energy consumption value of 18.x kWh / 100 km (my average since reset). I've always found the estimated range to be very conservative, on all my long drives. This directly contradicts your math.So, either, the battery is flat out underrated intentionally, it's rated at a higher rate of discharge than 1C (which I only assume, but don't know), it's rated at a colder temperature than my current ambient, the peukert coefficient is higher than I think it is, the SoC meter is wrong, or the energy consumption meter is wrong. Either way, I've been in a situation where I could potentially hit 150 km before, and I think I could today, if I wanted to push it.

[Huronlad 186]

Have fun figuring out what info from the car is inaccurate.

[steveyfrac 73]

Have fun figuring out what info from the car is inaccurate.

You don't think there's any chance I'm pulling more than the rated energy from the pack? I give pretty good odds of that. Mostly because the kWh meter is just an ammeter. Pretty hard to screw that up.EDIT:So, the battery is almost certainly rated for continuous discharge. But that doesn't describe my drive in to work at all. I was held up at construction twice for long periods, and I hit lots of lights. So, I can certainly pull more than 17.6 kWh out of the pack. Even ignoring the Peukert effect. Edited July 30, 2014 by steveyfrac

[SmartElectric 31]

I've taken my Smart ED down to zero SOC, and can confirm that the various dash gauge readings are non linear at best.For sure folks including me have done 140km on a single charge with a some amount of hypermiling.I can totally see 150km being possible with more care, and extreme patience.Personally, I count on my Smart ED to get me 80km round trip in any weather, any further is an adventure...

[steveyfrac 73]

I drove 54 km to and from work today.My trip back I got 11.9 kWh per 100km. This used 30% of my SoC. My estimated range remaining was 101 km at the end of the day. So my 150 I don't think is unreasonable...

[robm 1]

"Personally, I count on my Smart ED to get me 80km round trip in any weather, any further is an adventure... "my commute is 90 round trip. maybe I should go for one now and just take the other car on the coldest days here (just north of Toronto)?

Edited July 31, 2014 by robm

[Francesco 71]

My commute is way shorter, but now that the wife is finally working again, I'd like that to be the plan. My cdi and her Accord are both paid-for. Her commute is about 80 round trip, mine less than 30. We could honestly have the three cars cheaply, use the Accord for dog stuff and big items, and rotate the smarts for commuting until the coldest days.

[Alex 21]

The nominal kWh rating is likely conservative so you have the rated capacity under sub-optimal conditions and some age on the battery.I much prefer actual proven results over theoretical calculations, BTW. I believe Steveyfrac's numbers. Too bad my daily use frequently exceeds 200 km, rarely over 1000! No ED in my future.

[steveyfrac 73]

[i haven't seen anyone else discuss their displayed kWh / 100 km when hypermiling. I kind of want a benchmark for how I'm doing.If we had the European fast charger (22 kW A/C) , that let you charge the ED in an hour, you'd have no issue doing 200 km a day, so long as you could hit a fast charger at some point during the day! It'll come!--Steve

[Francesco 71]

I'm still not sure why it's not available here.

[steveyfrac 73]

I'm still not sure why it's not available here.

The European design is supposed to work off of 400 volt three phase, which isn't available here. It's a little harder to build in a 220v. But it would have been really nice to have a 7 kW or 10 kW charger.

[SmartElectric 31]

my commute is 90 round trip. maybe I should go for one now and just take the other car on the coldest days here (just north of Toronto)?

I'm not far from you. Recently I avoided recharging for a few days, taking the car down under 20% SOC remaining and got more than 100km driving with zero care for efficiency. There is comfortably another 30km of range left when my ED gets to 20% SOC. So total range with air conditioning periodically (wasn't an overly hot week) was well more than 120km.In the winter, I did the same test, avoiding recharging and got around 75km to 20% SOC remaining during one of the coldest weeks of the winter (-20C many days) when I ran the heated seats and defrost full blast for the entire drive.90 round trip would leave you using most of the battery on the most extreme winter day when you had to run your defrost and heated seats for perhaps half of the commute.Plus, around us, there are LOTS of folks who've put their EVSE up on www.plugshare.com, and a fair few public charge locations.I think the Smart ED is no problem for your commute. You'd be saving a bundle, probably 6$ or more per day in fuel alone, at least $100 per month. Plus. the ED is so much more fun to drive than a gas car...

[steveyfrac 73]

I'm a little worried about winter. Really don't want to have to plug in at work.

[RunSilent 15]

I think this is about the best you can do in reality. Use google translate to get the gist of it.

http://www.aveq.ca/blogue-smart-electric-d...bon-pour-160-km

Edited August 2, 2014 by RunSilent

[steveyfrac 73]

I think this is about the best you can do in reality. Use google translate to get the gist of it.http://www.aveq.ca/blogue-smart-electric-d...bon-pour-160-km

Thanks RunSilent!160 would be quite the reach for sure!--Steve

[SmartLikeTheWind 2]

When I drive back roads (< 50 mph) and keep the AC off, I regularly get about 100 miles total range (estimated from actual miles traveled and % SoC used). So 160km should be easy to do, just need to have a free weekend morning...btw, the energy consumption display on the dash (kWh/100km, or in the US miles/kWh) is highly inaccurate. It inflates the energy used. Don't use it to try to calculate anything!The SoC meter on the dash is pretty good. So if you want to calculate consumption, look at km traveled / % SoC used (or the other way around, as you like).

[marchanna 115]

I've exceeded 160kms on a single charge. I drove for about 5kms on 0% SOC to do so. Basically, you have to drive at a steady state under 80kms/hr making as few stops as possible. The SOC gauge is not linear - your first 20% and last 20% get a disproportionate # of kms. If driving in a straight line with a 20km/h wind at your back, it would be easy to exceed 200kms on a charge. I drove to Hamilton one windy day eastbound on hwy 8 and got almost 50km on my first 20%.

The rate of discharge can certainly gain you 36%+ more total energy output - one just has to take a look a the specs on commercial deep cycle batteries.

I've got 36,000kms on my ED now and have finally stopped monitoring range closely. I do however still have my data logger installed, which tracks all sorts of parameters. My normal use range expectation in 20 - 25c weather is about 140kms; -10c without HVAC is 110kms.

[steveyfrac 73]

Commercial deep cycle batteries display a lot more peukert effect than our lithium ion. None the less, I've done 80k on less than 50% SoC a bunch of times.

I actually regularly drive through the city now, instead of the highway. It's a sightly longer trip time wise, but it's shorter distance, and much more pleasant to drive. Plus I get to use kick down off more stop lights.

Net result, I end up with 14 kWh / 100 km pretty consistently.

[RunSilent 15]

Does anyone else have the paddle shifters for manual regeneration? I have to take a four-lane highway every day that has lots of steep and big elevation changes and ordered my car with them for that reason.

I find being able to turn the regen off makes the car much easier to drive at highway speed, and coasting down the long grades with zero throttle at 110km/hr is nice. Then being able to switch on full regen (which is double what the standard regen provides) while careening down the off-ramp is just like having a full engine brake on a big diesel, and I can come to a gentle stop without touching the brakes.

Of course, the uphills mean sometimes using the kick-down to pass the B-trains, but most of the time coasting into the hill with the little extra speed gained I can make the next crest without loosing too much speed and staying off the kick-down.