Sunday, June 24, 2007

"Body" -> Sing The Bicycle Electric Part 1

A number of years ago, Scientific America did an article on the world's most efficient animal for transportation. With a little help, the clear favorite was man.

What was the help that man needed?

A bicycle.

Bicycles are a marvel of engineering, and the amazing thing about a bicycle is how far you can go. When younger, I did a couple of double centuries, which is 200 miles.

However, as I age, I find myself getting slower, and with an extremely stressful job, the idea of bicycling can actually make my job more stressful. I mean, who wants to bike to work when you are stressed?

Plus, there is a nasty hill leading out of our community.

The answer to this comes with a neat invention: the hybrid bicycle. A bit like the hybrid car, which is ½ electrical and ½ gasoline, the hybrid bicycle is ½ muscle and ½ battery.

It would probably take me about 1 hour ten minutes to get to work if I was working moderately hard. With my hybrid bicycle it takes roughly 55 minutes without a lot of effort (pulse around 105 or so) and 45 with more effort (getting my pulse more toward 130 or so.)

The nice things is that I can decide not to work hard, or I can go as hard as I want. I find out having the electric option on my thumb really takes the pressure off. Knowing that you can relax at anytime, but knowing that you are going to be pumping some, actually allows me to ride more. Whenever, I start to commute on my electric bike, I ride quite a bit. Then when I ride one of other bikes, without a motor, I always find I've gotten into shape.

Now, I did have one person at work look at the bike and say, "well does the motor mean that you are cheating." This I think is rather silly, as this person was on her way out the door with her keys in hand. I said something like "what bike did you ride in today?"

You need five things for an electric bike:

1. A motor
2. A controller
3. A battery
4. A throttle
5. A charger

I have been riding an electric bike for over 5 years. I got into to it a bit by accident. Literally, by accident. I had been hit by a bus, and my foot got pulled apart. I wanted to be able to bike, but normal riding hurt when going up hills. I added the kit to help with my injury, and the rest is history.

Here is a picture of the motor. Often this is call a "can" as it really does look a coffee can. For my electric bike system, I used an "after market" kit called a Currie. It's not a half bad solution, but it doesn't offer a lot of power, but it certainly takes the edge off of any hill.

There are a wide variety of different motors. This is a chain driven motor, which means that it has a chain that hooks into the rear wheel (which is the picture right below this one.) However, this design has fallen out of favor because Currie had some financial difficulties and stopped supporting the design. It is tough to get parts now.

The most popular design is using a motor to replace your axle. Here is a hotlink to Google to look at some images.

Here is a picture of the back of the motor. You can see that I tucked it underneath my panniers (bike bags), and while it makes a little bit of noise, it really isn't much noise at all. As a matter of fact, you need to be on another bike to really hear it, or the street has to be pretty quiet. The design has a cute little clamp that is designed to snuggle around your spokes and clamp on the hub. This now gives the little Currie chain something to turn. The output from the motor is probably about 200-300W on average. This is pretty close to what I can put out when I am working pretty hard. You put the motor and me together, and we move up the hills pretty well. The motor does have a "power band," which means that it can only spin the wheel up to about 17 MPH. This is more than enough for me. In reality, I don't use the motor on the flat or downhills. I want the motor for the uphills.

The best thing about the Currie design is the mounting of the battery. I wish somebody else would come up with the same type of slick design, because I can't find any design quite as nice.As you can see in the picture, there is a very slick little case with some nice mounting hardware that situates the battery nice and low in the middle of your bicycle triangle. The battery pack can be opened and inside are two 12V 12 Amp/Hr batteries (in detail they are B&B BP1212T2).

Now, mind you, the whole battery scene is very interesting right now. I am rather retro in my approach to the batteries on my bike. Mainly because I got into this about 5 years ago, and the batteries certainly were not as advanced then. I now have a couple of good charges for my battery type.

The type of batteries I have is SLA or "Sealed Lead Acid" batteries. There are three down sides to SLAs.

1. They hate being left discharged for any length of time. This will quickly ruin them.
2. They don't empty very far. You can only empty about half of the available charge.
3. They are heavy. Two batteries are about 18 lbs. Added to the plastic case and motor, the electic bits on my bicycle add 35 lbs or so.

There are a couple of advantages.

1. You can leave them plugged in all the time.
2. They are cheap. I just replaced my batteries inside my pack for $60.

For me, I bike to work and I immediately charge them. I am in no hurry to replace my current system.

It is good to get some exercise, but it is a lot of fun to save money by doing it. My current alternative to biking to work is driving my car. Here is what I pay to get to work:

Alternative A: Direct Costs

Toll Roads: $3.00 round trip
Gas: $4.40
Wear and Tear: ~$2.60 (oil, brakes, tires)

Total cost saved: $10.

Alternative B: GSA Rate from the Government = .445 cents a mile

Mileage to work = 23.4M * .445 = $10.41

Either way it is about $10.

Now, I do need to charge my bicycle. Using my Kill-A-Watt Power meter, I can determine that I use about 1/2 of a kilowatt Hr. This cost 5 cents. Now, since I charge my bike at work, I only need to charge it once a trip at home. So, out of pocket electricity costs is 5 per day from home. I'll just ignore this cost.

So let's use $10 per trip savings. Since my original kit cost $400, it took 40 trips to pay it off, or 1000 bike miles. I've added a bunch of other stuff to my bike to be seen (more on this later), but I know that I have gone at least 3800 "alternative car miles" on this bike.

Very quickly, I will be over 4000 miles, which means that I will have saved roughly $1600 by bike commuting.

Even better, I am healthier because of it.

1 comment:

mark said...

Electric Bicycles and Electric Scooters

Elmo The Electric Bike and Electric Scooter Guy

This is an excellent blog for electric bicycles. There are not too many around like this. Thanks for making this such an interesting subject. Oh, by the way, Wired Magazine has a great article on hybrid cars this month. (Jan 2008 issue).

God Bless,