First Build: Big, Half-Fat E-Dummy

[Anthony King]

I'm anxiously awaiting parts for this build. I have a Big Dummy that I use to carry my children. Before moving to the country I was able to get almost exclusively on bike or foot, but now I'm in hilly New Hampshire in a tiny town and the nearest grocery store is about 13 miles away.

I'm converting my Big Dummy to extend my range so we can run errands in town by bike. I have a 100mm Pugsley fork and I'll be putting the motor on a fatbike front wheel. The rail-trail to town has some rocky and sandy sections, which is why I'm going with the large front tire. Can't afford a custom longtail frame with room for a fat rear tire, so for now the build will be half-fat.

Build will use an eZee front hub, 20A controller and 36V 20Ah Ping battery. I'll post pics and any questions as parts arrive and I start the build.

Thanks to all the knowledgeable folks who post in the forum, scanning these forums and the wiki, along with the simulator at ebikes.ca helped me figure out what I'd need for my build.

 

[Stevil_Knevil]

Sounds great! I loved my eZee-motored, 48V@20A FWD Big Dummy.

Hope you are using one of the replacements from Surly's recall of Pugsley forks -> http://surlybikes.com/pages/surly_bikes_recalls_bicycle_forks_due_to_fall_hazard/

 

[Anthony King]

Sounds great! I loved my eZee-motored, 48V@20A FWD Big Dummy.

Hope you are using one of the replacements from Surly's recall of Pugsley forks -> http://surlybikes.com/pages/surly_bikes_recalls_bicycle_forks_due_to_fall_hazard/

Mine was made before the recall batch, but thanks for the thought.

 

[Anthony King]

I just received my battery, which was the last component of the build to arrive.

I have a 25A controller and a 36V 20Ah battery from Ping. The battery charged and balanced quickly. I need to build a protective case for it. I've looked at the eZee hub installation guide from ebikes.ca and everything looks fairly simple. I do have a question.

I need to attach male Anderson connectors to my battery wires to connect to my controller. I assume the 25A controller from ebikes.ca uses 30A Andersons, but the outer dimensions of the 30 and 45A are the same. Does anyone know which connector is used on this controller so I can attach the correct male Andersons?

 

[Anthony King]

Got the connectors to hook up the Ping the the controller (45A Andersons) and cludged together a broken Hall wire to get this thing rolling today.

I was advised to take the bike for a few short rides and recharge the battery before doing a deeper discharge, so I went on four short rides (tried to keep it around 1.5Ah) and then went to the town common to pick up a celebratory beer and test the bike coming up the hill to my house (412ft of climbing in 2.2 miles).

The motor seemed a little jerky when the throttle was wide open and on the steepest grades, but worked smoothly if I pedalled and backed off the throttle a little. I averaged 12.2 miles up the hill and felt like I'd been pedaling on flat ground, which is heartening. When I got back the kids were home and I took them to a nearby farm to pick up some blueberries. The way back home is a decent half mile hill. The bike seemed to go just as well up the hills with 80 pounds of kids on the back as it did unloaded.

I'm not at all happy with the Pugsley front wheel. Replacing the Big Dummy fork with the Pugsley fork slackened the head tube angle on the bike, and combined with the monstrous contact patch of the nearly four inch tire the bike has waaay too much trail. Getting the wheel to turn is a chore.

I have a pair of 24" wheels w/downhill rims for this bike and I'm going to rebuild the hub motor into the front wheel and get some 24" slick-ish tires. The smaller diameter will reduce the trail and improve the handling . I'll also get better battery range since the wheel will be significantly smaller than the Pugsley (nearly five inches smaller diameter).

Aside from the wacked out front end geometry I'm pretty optimistic. The simulator at ebikes.ca says I'll improve battery range quite a bit with the smaller wheels. Hope so. I didn't have any cargo today and I chewed through 5Ah to and from the trailhead I'd like to take into the city for errands.

So I guess the Half-Fat E-Dummy will be short lived. As soon as I can get in the right tires I'll swap the motor into the 24" wheel.