The Electric Madsen

Family life around our house has entered a new era with our newly electrified Madsen cargo bike! With 3 kids under 6 we've been searching for the solution to transport them, and the Madsen with it's bench seats and social atmosphere is the new favorite. Only problem, house to town is a good 5-7 miles with hills up and down, and some days the old legs just aren't up for that (see previous post ).

But the solution to this problem came with the installation of an eZee electric motor kit. The motor wheel replaces the 26" front wheel, and controller and battery conveniently mount in the frame between the downtube and the bucket. A little creative engineering with some velcro straps and zipties and the lithium battery was mounted. The battery weight is suspended from the upper frame tube and the straps wrap around the lower tube to keep it from swinging. The little piece that keeps the super long Madsen chain aligned also doubles to keep the chain and battery separated. The eZee battery itself is in a nice plastic case with a switch, so is protected from the elements somewhat. Removal of the battery for charging involves undoing the straps, but once I got this system down, that became pretty trivial. I like the way the battery is low on the bike and not too obtrusive or taking up any of my bucket space. The wiring is also all conveniently kept together.

Mounting the motor wheel in the front fork was not too difficult until we got to setting up the disc brake. The eZee kit is disc brake compatible and comes with a rotor, however, the brake that is supplied with the Madsen was not compatible with the wider hub. No problem, a new brake (Avid BB7) was ordered up and installed. The 180mm rotor that came with the eZee kit paired with the new brake and only a few additional spacer washers were needed. Once the brake issues were worked out, it was just a matter of making sure the bolts were properly tightened. A tire change wasn't even necessary because the kit comes with the Schwalbe Marathon Plus tire already installed (and puncture resistance is a good thing on these motor wheels!)

The eZee kit operates with a handlebar mounted throttle. This replaces the right grip, and since the Madsen has trigger shifters there were no compatibility issues there. An LED battery gage also goes on the handlebar to keep track of battery useage. 

Once the kit was on the bike, we 

flipped the switch on the battery and that baby came to life! The ride home was a breeze as those hills melted away under steady pedaling and electric assistance. 

Last weekend, we tried out the new electric Madsen with not one, but TWO trips into town with everyone. First on Saturday morning, everyone loaded up for a trip to the Farmers Market, where we loaded up on greens, strawberries, and yummy treats from our awesome local growers. Then after a break at home for naptime and lunch, it was back downtown again for a kids festival put on by the local La Leche group. Music, hula hooping, and fire truck tours later, we took shelter at the shop from a sudden afternoon downpour, and then picked up tacos at the mobile taco truck on the way home. Kiddos were all tired and one even lay down for a nap on the way home! Overall a great day, no cars involved, and it wouldn't have been very possible without electric asisst. I think the new Madsen is going to be seeing some light in the weeks to come.

-Elise

Morgan on HomePower Hour discussing Lithium batteries

Morgan was recently interviewed on the Home Power Hour, explaining a bit about how the batteries work and are kept happy by the Battery Management System. Listen in here.

Expanded weekday hours

We're moving into a summer schedule at the store now and have expanded our weekday hours. We'll now be open:

Tues 10-6

Wed 10-7

Thur 10-7

Fri 10-7

Sat 9-6

Sun 12-5

Mon closed

Also, you will be seeing a new face around the store. Please welcome Erica to our team of helpful staff!

Solar at Shakori Hills: does it make sense?

We had the pleasure of making it out to the Shakori Hill Festival today to let the kids participate in various events such as the Paperhand Puppet Intervention, and to listen to a bit of good music.

The organizers had a booth there, asking for contributions towards a solar electic system that would power the event in the future. The card indicates that 10,000 kilowatt hours (kWh) of electricity are used to put on the event. I applaud their goal to get off the grid. But the sea of cars I saw in the parking lot left me wondering: how much energy was used in just getting people to/from the event, in comparison to the 10,000 kWh goal?

Here's my attempt to figure it out. When we were there on Sunday, there were perhaps 700-900 cars around. We can estimate from that a total of about 5,000 cars were driven to/from the event during the course of the four days (that's an average of 1,125 cars/day, or 2,250 people per day if it averaged 2 people per car, probably a low estimate). The location is 17 miles from Carrboro, 40 mi from Raleigh, 35 mi from Durham, and 10 mi from Pittsboro. So we'll average all of those at 25 mi (each way), for an average round trip of 50 miles. The fleet average for the US automobiles as of 2003 was 25 miles per gallon, so on average, 2 gallons of gasoline were burned per car trip to/from the festival. If our estimate of 5,000 car trips is accurate (maybe an underestimate?), that's 10,000 gallons of gasoline burned up (526 barrels of oil).

Now, hold onto your seats. Each gallon of gasoline contains about 37 kilowatt hours (kWh) of energy. So, we have 10,000 * 37 = 370,000 kWh of energy burnt up to get people to/from the festival in their cars/SUV's/trucks/motor homes.

That is, 37 times more energy were used to transport people to/from Shakori Hills, than would be saved if the festival organizers reach their goal of going all solar.

Here's another way to look at it. An efficient generator will extract about 7 kWh of energy out of a gallon of gas (no, they are not very efficient, they only recover a small part of the 37 kWh contained in a gallon). So, to generate the 10,000 kWh of energy that the festival needs to run, that is about 1,429 gallons of gas, if they were to use local generators. Compare that 1,429 to our estimate of 10,000 gallons burned up getting people to and from. I.e., even using inefficient gas generators, generating all that power to run the festival would only take 1/7th the power that is consumed to get all those people to/from the event. 1/7th. That is sobering. (and note: even if everyone drove a super efficient hybrid like the Prius out there, and averaged 50mpg, it would still consume more than 3x more energy to transport people there).

And this is why all the peak oil people are so concerned about our future. They realize how much energy we are just burning up driving around in our gasoline burning cars. But most people don't think about that. Even very "green" people just don't realize how much energy is contained in each and every gallon of gas put into their cars. And, while I applaud the goal of Biodiesel, I had a look at the Piedmont biofuels website to see how much they produce. They produce "thousands of gallons per day" - so, basically, if every person going to the festival used biodiesel instead of fossil fuel, there would be none left in this area for any other purpose (such as powering tractors that help grow our food).

I don't want to come off as overly critical of these efforts. Every small bit helps. But if people think these are solutions to fossil fuel dependency, they are clearly not. They are drops-in-the-bucket.

Anyway, I think if the Shakori Hills organizers can get the solar panels, it will save energy and have a positive effect - not only by the direct power saved, but by the example set. At the same time, they could have a vastly greater effect on energy usage for the festival (and also local pollution/noise/danger created by the cars) by implementing a bus system to/from the event. Or getting people to go out there on their electric bikes :)

Why some days just need an electric bike

Some may accuse me of being heavy handed in promotion of electric-assist for bikes. To me, this is not a marketing schtick. It is an education schtick. Ever since I got my first electric motor kit for my bike in '94, I've shown it around, and many people - especially avid cyclists and bike shops - have been dismissive. I think this stems from an attitude that bikes are a recreational tool rather than a transportation tool. After hearing that attitude for all these years, perhaps I've grown a bit defensive about it over time. But, really what I want to accomplish is education - letting people know that electric bikes exist, and can help many people with the goal of biking more often (i.e. from none at all to at least once or twice a week would be a big step!).

So, to do that, I like to tell little stories about my experiences, and here is the latest. We recently became a Madsen Bicycles dealer, and got some of them in stock. One of the things that is exciting about this bike is the ability to haul up to four kids at a time, all sitting nicely seat-belted on benches in the rear bucket.


This is a Good Thing for those of us with families that exceed the carrying capacity of the Xtracycle, Yuba Mundo, or Big Dummy (all of which carry only two kids, max).

So, I have been using the Madsen for short trips hauling kids around the local area, and it is great. But our area is hilly enough, that hauling 120 pounds of kids up the hills is a slow endeavor. The first hill starts right at my driveway, with a 50 ft climb. And there are many more hills riding around Carrboro and Chapel Hill (this is the Piedmont, after all). So we have been planning on putting an eZee electric hub kit on the bike, but presently they are out of stock at our store, so the bike is currently un-assisted.

Anyway, on the Saturday of Easter Weekend, I was taking the kids for an Easter Egg Hunt activity put on by a local organization. I really wanted to bike over there with them, rather than use the car, because it was a beautiful, sunny, 70-degree day. By the time we got the stuff together, we only had 45 minutes to get there. If I knew exactly where I was going, and if it was on the closer side of town, that would have been enough time to ride. But I didn't know that area of town well, and I recall that part being quite hilly. Well, anyway, we loaded up into the bike and started up the first hill out our driveway, and I quickly realized that I just didn't have the energy to haul these kids over all those hills for about 20 miles round trip, while being in a hurry to get there on time (and possibly getting lost in a hilly area of town). So we turned around, back down the hill we went, and we got in the car and drove instead.

Now, if we had already had the electric assist installed on this bike, I would not have hesitated to go by bike. The hills would have been much less of an issue, and I also would have felt less time pressure, since I would have saved 10-20 minutes of riding time.

So here is a case where if I had electric assist, I would have gotten well over an hour of moderate exercise pedaling the assisted bike to and from the activity, whereas instead I got none (and didn't have time for another bike ride that weekend). And, I burned up well over 37 kWh (kilowatt hours) of energy by driving the car over, when the e-bike would have burnt up much less than 1 kWh.

Someone who lives in a flat place (e.g. Davis, California or much of Texas) reading this might not be able to relate. One thing I've noticed with my Big Dummy cargo bike is that when it is fully loaded, pedaling it on the flat lands is only a tiny bit more energy than pedaling it unloaded. But once it gets to a hill, all that extra load weight becomes very noticeable. So, anyway, if I lived in a flat place, pedaling the Madsen with the kids 10 miles each way wouldn't have been such a big deal. But with these hills, it is a big deal - enough so that it makes me much less likely to use the bike, and instead, just take the car. I'm looking forward to having that assist on there! (Aside: These bikes are now available for rent for trying out).