BamaBoy

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Fuquay Varina, North Carolina, United States
A guy finding out if life really does begin at 50.

Monday, September 29, 2008

EV on a Budget

Before I got my S10 EV back in July I had ordered a DX bike kit from Zap. It's been on back order since June and it finally came while I was in Boston. The DX is a dual motor 12v kit that you simply bolt onto your existing bike. Goes ~18mph with a range of about 15 miles depending on how much you pedal. It has a regenerative mode which is suppose to help charge the battery when you coast downhill. The motor will assist you as you pedal or you can just sit back and let it do all the work. Going up hill you have to pedal but the ad said... "Lets you take hills like an athlete." If the battery runs down you can just pedal like a normal bike.
As you can see the kit came with everything I needed. The black item in the center with the white "Zap" on it is the pouch for the battery. The motor is just below the pouch, to the left of the small black rectangle which is the battery charger. The silver item on the far left with the black stripe is the battery holder/mount. Inside of it is the motor control module - more about that later. The battery is the large gray rectangle in the middle. Notice the water bottle and cage on my old Cannondale. It has to go to make room for the battery mount. Bummer.
The battery is valve regulated sealed lead acid, so it is heavy. ~16lbs. Yuck. 18amp hours. There is an auxiliary connector that allows you to charge the battery while it is still connected to the bike. Or you can pull the Velcro apart and remove the battery pouch from the bike. The pouch has handles to make carrying the battery easier.
Here is it all installed. Simple. Took about an hour. The battery holder mounts to the frame using pipe clamps. The small black button on the gray battery mount is the on-off switch. The pouch has flaps that mate with the Velcro on the mount and a strap that loops under the mount. The battery is secure, and isn't going to fall out.
The motor mounts to the seat stay with a metal plate. Took a bit to get it adjusted so that the motor will try to 'climb' the tire as it pivots into the tire. This increases the motor's grip (friction) on the tire as the motor shaft rotates. If you pedal (or coast down hill) faster than the motor is turning the tire will push the motor away. Simple but effective design and seemed to work well. There is a lever to lock the motor against the tire if you want the motor to do all the work.

I wish I could say it worked 1st time, but it didn't. I hooked all the connectors up, charged the battery, but nothing happened when I pushed the handle bar mounted switch. Forward for high speed, back for low speed, and center(auto-return) for off. Took me about another hour to debug the problem.
The white/rust colored 3 pin connector in the lower left was shifted over to the left one pin. So only two of the three wires were mated to the pins on the control board. The 'root' cause was actually the large wire next to the 3 pin connector. That wire (spade) connector was flipped so that fat part was towards the 3 pin connector which prevented the white header from being able to slide onto the pin on the right next to the wire. Twisting the spade connector 180 degrees put the 'fat' part away from, and the thin part of the spade towards the 3 pin connector. This allowed enough clearance for the white header to slide over that first pin. No wiring diagram, and of course nothing is labeled. The correction is pictured here.

But after getting the 3 pin connector right, I when for a test ride and I have to say it easily pulled my 225 lbs along at a faster than I pedal normally pace and climbed reasonable grades (small hills) by itself. For sure I will have to pedal some to get up any real hill with the motor doing most of the work. Still too early to judge the range. But I have to say that this kit can take the hard work out of bike riding, while still giving you some exercise. If getting all hot and sweaty riding to work is stopping you from doing it this kit could solve that problem.

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