Monday, June 11, 2012

48V 1000 watt Ebike Kit

I picked up this 1000 watt kit to add some extra power to a 450 watt ebike kit from Currie that I got last year. The 450 watt kit is fine, but it is louder, and slower than I expected. The chain drive on the Currie kit needs a lot of adjustment, and it is very hard to change out flats or the like when I get them because the Currie kit mounts on the rear. My bike just doesn't like it really.

By the way, the reason I have that specific bike is because I wanted the dual suspension to transfer less bumps to the motor controller and batteries. Vibration in general is bad for batteries. That necessitated re-engineering the Currie battery holder so it would mount on a non-fixed rear wheel. The bike itself is also very sturdy thick walled steel tube, which should help it last with the extra 70 labs of batteries, motor, and controller stuff on it.

I was originally going to put this kit on with the currie kit. I rewired the switch on the Currie kit so that one direction would put the two 24v batteries in parallel, and the other way in series (either 24 or 48v). that way I could use either motor. After trying this kit, I decided to scratch that idea and use only this 1000w 48v motor with the 2 Currie SLA batteries. I didn't want the extra weight of the motor that I would never use.

The motor is 470 rpm. That sounds low, until you do the math. On a 26" rim, 470 rpm means 38,370 inches per minute. That is 36.3 miles per hour. So up to that speed, you can hit the throttle and get an assist. It was quite weird when going down a long, steep downhill to hit the throttle and feel the motor provide even more speed. This motor is FAST.

I was actually concerned the first time I used it because of how fast I could go. Several of the roads I travel on used to worry me because of the speed differential between me and the rest of traffic. On the Currie kit, I could do roughly 14 or 15 mph. In this, I am easily double that speed. I keep up with traffic on a 35mph speed limit street.

This does use a lot of power though. On the Currie kit, I could get about 10 miles of range using both batteries when they were brand new. On this kit, I get 4.5 miles max range. Part of that will be the wear on the batteries after a year of use, and some will be because of the excessive wind resistance at high speed. I have only been using this kit for a few days, and I haven't tried going the same speed as my old kit to see if the range differs. It is way too much fun to firewall the throttle and keep it there.

The cables are nice and long too. That was something that annoyed me greatly on the Currie kit. This kit also comes with brake levers that have a cutoff switch on them that cuts the motor. The levers are much longer than the ones that came with my bike, which was perfect to span the extra distance on the handlebars that the thumb throttle takes up.

A few 'gotchas' on this kit:
The directions are very badly translated. I used them more as a reference than as instructions. If this is your first electric project, pick a different kit. The wire harness is not marked, and several connectors can be interchanged. When my kit came, most of the connectors were connected already, but needed to be disconnected to be put on the bike. Make SURE to mark them before disconnecting them. In fact, almost nothing is marked. The controller has '48V' marked on it in pencil, but the motor on the wheel had '48v' engraved on it.

The wheel/motor does not have a direction of rotation on it. I put it on backwards the first time. I could have went very fast in reverse, but it was hard to steer, so I flipped the wheel around. The tire is 1.75" wide, which is thinner than the 2.25's that my bike came with.

Also, something I didn't think about was that since this is on the front, if you apply the throttle when the front is unloaded, it will spin the tire. I actually burnt a throw rug in my house when I did this on accident after I assembled the kit on the bike. I did it again later when I started moving in some gravel, and I ended up digging a hole with the front tire.

If I were doing this all again, I would get 2 Currie batteries, the battery rack, and this motor kit. I like the Currie batteries and rack because they keep the weight low and look professional, but this motor and controller is awesome power-wize compared to the Currie kit.

Here's some links to the other items I talked about:
24v Currie battery
24v 450w Currie Kit
1000 watt kit
Magna Bike itself