Bike ride to Triad Electric Vehicles Association meeting

Today I just got back from a nice bike trip with my daughter, to the Triad Electric Vehicles Association meeting, in Burlington, NC. I was invited to their monthly meeting to give a presentation about Lithium batteries and battery management systems, since some of the members are starting to contemplate moving away from lead acid batteries. In fact, two of the members have recently commissioned us to build custom packs for their EV's.

We rode over there on my electrified Surly Big Dummy, with an eZee electric kit on front. We had 3 different LiFePo4 battery packs (48V x 10 amp hour (Ah), 2 x 36V x 10 amp hour, totaling about 1200 watt hours, which equals a 100 watt lightb

ulb running for 12 hours). I didn't really expect to use that much battery power on the 33-mile each way ride, but I brought them for show and tell (and glad I did). I also brought some BMS boards (designed by the folks on Endless Sphere), PSI cells, and more. We also had all our overnight gear. So the bike was well loaded with us and all our stuff. I estimate that the gross vehicle weight was close to 400 lbs with us included.

While a round-trip 65 mile bike ride may not sound like a big deal to some folks who ride their road bikes 60+ miles in a day, this was a ride with precious cargo on the back, and a fully loaded bike, on some sections of busy road. I planned the route using Bikely.com, which allows mapping out a route using Google maps. I tried to choose a lower-traffic route most of the way, but some high-traffic stretches were unavoidable (why don't they put shoulders on the roads in this part of the USA????)

We started out mid Friday afternoon, hoping to make it there before the main rush hour traffic hit. As soon as we got on the road, there were some serious headwinds. The national weather service reports winds averaging 15mph, with gusts up to 43 mph - coming straight from the direction we were going. I was sooooo glad to have electric assist. That would have been a miserable ride without. At one point, I was going full throttle (using about 1,200 watts) and pedaling full tilt, on flat ground into the wind, and only going about 15 miles per hour. Without electric, that would have been about 6 miles per hour. There were also some nice hills, too (totaling about 1,200 feet of up and down). Without electric, and with that headwind, the trip would have easily taken at least 4 hours. Despite the winds, we made it there in 1hr 45 min, at an average speed of just under 18 mph. But we burned up way more energy than I planned - about 24 watt hours per mil

e. (i.e., four miles riding would equal a 100 watt light bulb running for an hour). I had planned on 20 watt hours per mile. Glad I had those extra batteries!

Jack, one of TEVA's leaders, graciously hosted us for the evening and let us crash at his place. We had a nice dinner and after-dinner discussion about quantum mechanics, consciousness, God, and evolution (I am making slow progress on a book about these subjects). We also had the obligatory discussion of the current financial "crisis". Anyway, to bed very late, and up somewhat early next morning to head out for the meeting.

So I'm not someone to get shy in front of groups of people, since I give scientific lectures fairly regularly (just gave one last Thursday to an audience of 40-50 people). But this group was a bit intimidating, because there was only one other woman present, and it was about 20 guys, who were obviously quite tech savvy. Well, after some introductions and whatnot, we got down to business and I started describing the ins and outs of Lithium Iron Phosphate (LiFePO4) batteries for electric vehicles. I talked about keeping cells healthy, the benefits and drawbacks of these batteries, and discussed some basic design elements for battery management systems (BMSs), the electronic systems that keep cells healthy. There was some good discussion and questions. Afterwards, we went out to the parking lot to check out the various EV's there.

Here's an interesting observation that one of my hosts made: I was one of only 2-3 people who actually used an electric vehicle to get there, and mine was a bicycle.

This was a very interesting observation, so I'm going to sidetrack for a second on that. Why didn't more people drive their EV's over there? I can only guess: I think the biggest reason is that of the various people I talked to, many people had lead-acid battery packs that weren't performing too well anymore, or didn't have sufficient range, or... etc. One guy mentioned a story about being out in his EV one day and getting stranded when the batteries ran out, and having to walk 3 miles. So here's the interesting thing. If a bike battery runs out, you can still pedal the bike. Even my nearly 400 pound cargo bike, if I had to, I could pedal it that whole distance. But I think the bigger take-home message is this - the main impediment to people using their EV's more often is the batteries. For a bike, the battery is relatively small, and hence (though not cheap), not nearly as expensive as for a car or truck-sized vehicle. So nowadays, many people use lithium or at least nickel batteries on bikes, whereas most electric cars of the hobbyist variety are still lead acid. One older gentleman even prodded me a bit because he said he had access to very cheap lead acids, so he didn't see why it was worth buying lithium batteries. I understand that point of view, that in an ideal world lead acids can run for a very long time, so why pay (lots) extra for LiFePo4? But, being in the e-bike repair business, I have seen so many "dead" e-bikes simply because the batteries died, and people hate having to replace them every few years. And it gets worse when you put them in a series string to produce higher voltage. Aside from the longer life and lighter weight of lithium, there is the lower hassle factor. If you get a working system with a good BMS (very important), it should give many years of service without issues. I used lead acids for many years before I switched. But now that I've "seen the light," it is hard to fathom ever switching back to the heavy, bulky (though cheap up front) lead acids.

But anyway, some people tried out my Big Dummy and had lots of fun. Then a bunch of the members headed off to the Earth Day fair in Greensboro, and we got headed back to Chapel Hill/Carrboro.

This time, the wind was at our backs, and still pretty strong. Sweeeeet! There were a bunch of times we were cruising along with just pedaling, no electric power at > 20 miles per hour, a good clip for a 400 lb cargo bike. We made the return trip in just under 1:30 hrs, averaging almost 19 miles per hour, and using about 16 watt hours per mile. After a nice stop at a friends' house along the way, we got back home. And after just having biked 68 miles on a fully loaded cargo bike in 1.5 days, I wasn't totally wiped out (I definitely got some exercise, but not to the point of being wiped).

Total stats for the trip:

-Average 18.4 miles per hour

- 67.85 miles

- 3:40 minutes riding time

- 19.9 watt hours per mile

- total energy used by bike, 1,350 watt hours (for perspective, a typical gasoline powered car would use this much energy to go about 4-7 miles). I probably burnt another 400-600 watt hours from leg power.

I was nicely surprised by how well most drivers treated us. There was only one situation that made me nervous, a stupid dude in an ancient camper truck passed us at the same time there was oncoming traffic, and only gave 6" to spare. I don't know what his deal was, but maybe his engine couldn't handle slowing down on the somewhat steep uphill we were on, without stalling. Anyway, here's a plug for rear-view mirrors: I knew the guy was cutting it close, and I was prepared to bail out onto the grass if he got any closer, long before he was upon us. I don't know how any cyclist can stand riding without a rear-view mirror. I use mine constantly.

But anyway, most drivers gave us wide berth, and we had a really nice ride through the countryside of the piedmont.

3 cheers for human-electric hybrid vehicles!

Work and pleasure

Today I got to combine work and pleasure: I rode 38 miles round trip on my electrified Big Dummy (the Firefly) to Duke University. I gave a seminar on Bioinformatics, and then rode home. It was a cold day out (at least for these parts), with my ride home dipping well below freezing. I brought along a thermos with hot tea, and stopped several times to top off my tea cup (mounted in my handlebar beverage holder). On the way home, I even stopped at my favorite place to waste spend money, A Southern Season, to buy some more tea and sundries.

Why is such a trip even of note? For a couple reasons. First, today we spoke to one of our bicycle suppliers on the phone. He was asking us about electric assist, and saying that he didn’t really “grok” (understand) the whole electric bike thing.

Today’s trip is a perfect example of why an e-bike works. I have ridden many miles on road bikes; I could have ridden the ~40 miles on my (non-electric) road bike on a recreational ride in better weather - easily. HOWEVER, I wouldn’t have done that in a down coat, with insulated boots, with a thermos of tea, with a handlebar stereo, with a large U-lock, with a full change of dress clothes (to give the talk), with my computer, with a full array of bike lights for after dark, and other miscellany. If I had ridden my road bike with that assortment of gear, I would have arrived very tired out (and also about 1 hour later).

With the e-bike, I got two hours of exercise (I was pedaling moderately the whole time), but I did the trip in luxury (especially since the Big Dummy allows me to carry so much stuff). I never got cold, since I had plenty of spare warm gear, and big heavy duty boots, down parka, etc. I was drinking hot tea for the whole ride there and back. I had good tunes. In the narrow, fast moving parts of the road, I used the electric assist to keep my speed faster to not impede traffic. I hauled my load of stuff up some steep hills without problem. I arrived for the seminar feeling good from the ride, but not worn out. I left after the talk with plenty of energy, and had a (mostly) pleasant ride home, through some back neighborhoods up some very steep hills (to avoid the more traffic filled routes).

Simply put, I wouldn’t have done this trip without the electrified longtail bike. I would have ended up driving a car. Comparing the energy usage of that:

Car: 25 miles per gallon. That’s about 1,320 watt-hours (KwH) per mile. If I still had a Prius, that might have been as good as 45 mpg (doesn’t do as well in cold weather), or 733 watt hours per mile. In other words, each mile traveled in a Prius would have consumed the equivalent of 7-hours running a 100 watt lightbulb. For the whole trip, that would would amount to 27 kWh - the equivalent of leaving a 100 watt lightbulb on in my house for 278 hours or 11 days straight (that’s with the more efficient Prius!)

Bike: 18 watt hours per mile (about 1,833 miles per gallon). The whole ride consumed 684 watt hours of electricity. That’s equal to less than one mile in the Prius, and about 1/2 mile in the big car! I could charge my battery with the equivalent of 7 hours of 100-watt lightbulb usage, easily doable with the solar panel on my roof.

Why highlight the stark difference? Simple: I never used to think about how much energy I was using when I got into the car to drive. And I suspect most people don’t. Gas has been so cheap for so long, there is no motivation to think about it. But, when put in the above context, it is all the more clear how much energy it takes to move that hulk of steel around. It doesn’t matter whether the car is electric or hybrid or whatever. It is heavy, and it travels fast. Both of those factors mean that it is intrinsically inefficient, and consumes a lot of energy. For those folks concerned about CO2 emissions, the above numbers say a lot.

But here’s the sad part. I studied the maps carefully before going, to find a route where I wasn’t going to be fighting traffic. And the best route I could find was far less than ideal. There was a 5-mile stretch of former country road, that is now used by commuter traffic. It was busy. It was narrow. It had no shoulder. And it was the least of all evils connecting the towns of Chapel Hill and Durham. Sure, I know about things like “ride big” and “take the lane”. I did those things. But as I watched in my rearview mirror for approaching traffic, it was a constant concern; would the car slow for me? Would I have to get out of the way? Statistics show that for slower-paced roads, concerns about being hit from the rear are overblown. That doesn’t change the basic human instinct to want to know what is going on behind, and not liking having a zillion cars whiz by. It is the number one reason more people don’t bike.

It just seems absolutely crazy that two neighboring college towns, Chapel Hill and Durham, don’t have a reasonable bike route connecting them. I blame this firmly on the old boy network in North Carolina’s DOT. Maybe I shouldn’t say this on a public blog, but those guys need to get their heads out of their rear ends and realize that we are in the 21st century, not the 1950’s. Maybe in the 1950’s we needed more roads to be built; now we don’t. Now, we need more bike paths, sidewalks, railways, and other means for people to get around without burning ridiculous amounts of energy. And doing this would benefit the drivers too - it is never fun for a cyclist to be passed by a bunch of cars on a narrow busy road. But it is no fun for the drivers, either. Building out infrastructure to appropriately accommodate both would make everyone’s lives better.

Would I do the trip to Durham/Duke again? Yes. It was great. Much better than sitting in a car or bus. I got exercise, and an adventure, all wrapped within some important work-related business. I would probably plan my ride for a bit less busy time, if possible. But, regardless of whether I would do it, most people just won’t face such a ride, without the kind of experience I have commuting by bike. And some people think I’m crazy, anyway. To get more people on their bikes, and less people using up tremendous amounts of energy to move metal boxes around, we need to invest in bike facilities, now.

Why isn’t that part of the economic stimulus?
(note: there are token amounts in the stimulus for bike paths, but they pale in comparison to road funds).