Hi folks. This is an awesome forum, and I thought I'd post pics of my first build. Thanks to everyone who helped out with my newbie questions. I got a 2011 Kona Nunu hardtail 26" bike to build on. The frame is fairly small with a compact main triangle.
Here it is wired up with the GNG 450w kit (ordered from middriveebike.com) with stock everything. I'm using an AllCell 13aH 48V Li-ion pack. As you can see, battery is stuffed in an ugly bag on the top tube and wires hanging off the downtube. Ugly but ride-able. I also added a Cycle Analyst v3 for fun. I will have to say that I haven't encountered some of the problems reported by others about this kit. For example the "sparks" that fly from hooking up the battery. And, I don't really have a problem with "jack rabbit" starts, although I do feed the throttle through the Cycle Analyst which has a programmable ramp rate on throttle. And, knock on wood, so far the stock BB spindle is still holding up.
The main area that I wanted to "innovate" in was to clean up the look of the battery, controller, and misc wires. I toyed with the idea of making a metal box, but limited access to the needed tools ruled out that option. After riding the bike up and down steep SF hills for a couple of weeks, I concluded that the battery and controller never got hot or even slightly warm. Thus, I felt that a ventilated wood box would work. It doesn't rain here that much and I decided too that if it were raining, I would not want to commute by bike anyway. A little sprinkle would be ok, but the design goal was not to withstand a heavy downpour.
So, I designed a 2D/3D box and went to the local TechShop to laser cut it. It's made from 0.2" plywood.
Gluing up the box. The AllCell battery fits in the main box, while the controller, switches and wires fit up front. Note that the controller is exposed on the underside to air and on the left side, where the FETs are mounted. Water should flow off the box without too much trouble. I added a recessed key switch, a XLR charge port, and on the other side a 25A circuit breaker and a kill switch. Also added to the wiring is a 48V relay with protection diode to switch the main power.
View attachment 2
The box bolts to the downtube via the water bottle cage bolts. Two "wings" on the left side of the box clamp to the seat tube. Additional "cargo straps" wrap around the battery and through the bottom of the box around the down tube to further secure the battery to the frame of the bike. Here you can see the battery and all components installed and wired.
The right side panel is now installed with key inserted for first "smoke test".
I can report that everything works as expected! I'm happy that the box seems quite sturdy and the weight is all held securely in the middle of the bike, keeping everything nice and balanced.
TODO
The bike is running pretty smoothly, getting me through SF very nicely. The main problems now that I have are well documented.
1. The belt drive howls like mad and wears out after a few days of riding. I've got to upgrade to a better system, and hoping that LightningRod's new wider belt will do the trick! SpinningMagnets suggested that I file down the teeth of the motor gear to lengthen the life of the belt. I haven't done this yet.
2. The idle pulley on the secondary side constantly "falls off" meaning that I have to get off the bike and re-thread the drive chain. Again, maybe the LightningRods adjustable sheets will help here, by eliminating the pulley all together? On another thread I see that someone replaced the red idle gear with a plastic wheel with sides that is likely to have the chain fall off. Are there other solutions?
3. I have to add a throttle cutoff when the hydraulic brakes are activated. This will be wired to the Cycle Analyst.
4. I would like to replace the stock GNG throttle with a thumb unit.
Other than that, I couldn't be happier with the bike!
Here it is wired up with the GNG 450w kit (ordered from middriveebike.com) with stock everything. I'm using an AllCell 13aH 48V Li-ion pack. As you can see, battery is stuffed in an ugly bag on the top tube and wires hanging off the downtube. Ugly but ride-able. I also added a Cycle Analyst v3 for fun. I will have to say that I haven't encountered some of the problems reported by others about this kit. For example the "sparks" that fly from hooking up the battery. And, I don't really have a problem with "jack rabbit" starts, although I do feed the throttle through the Cycle Analyst which has a programmable ramp rate on throttle. And, knock on wood, so far the stock BB spindle is still holding up.
The main area that I wanted to "innovate" in was to clean up the look of the battery, controller, and misc wires. I toyed with the idea of making a metal box, but limited access to the needed tools ruled out that option. After riding the bike up and down steep SF hills for a couple of weeks, I concluded that the battery and controller never got hot or even slightly warm. Thus, I felt that a ventilated wood box would work. It doesn't rain here that much and I decided too that if it were raining, I would not want to commute by bike anyway. A little sprinkle would be ok, but the design goal was not to withstand a heavy downpour.
So, I designed a 2D/3D box and went to the local TechShop to laser cut it. It's made from 0.2" plywood.
Gluing up the box. The AllCell battery fits in the main box, while the controller, switches and wires fit up front. Note that the controller is exposed on the underside to air and on the left side, where the FETs are mounted. Water should flow off the box without too much trouble. I added a recessed key switch, a XLR charge port, and on the other side a 25A circuit breaker and a kill switch. Also added to the wiring is a 48V relay with protection diode to switch the main power.
View attachment 2
The box bolts to the downtube via the water bottle cage bolts. Two "wings" on the left side of the box clamp to the seat tube. Additional "cargo straps" wrap around the battery and through the bottom of the box around the down tube to further secure the battery to the frame of the bike. Here you can see the battery and all components installed and wired.
The right side panel is now installed with key inserted for first "smoke test".
I can report that everything works as expected! I'm happy that the box seems quite sturdy and the weight is all held securely in the middle of the bike, keeping everything nice and balanced.
TODO
The bike is running pretty smoothly, getting me through SF very nicely. The main problems now that I have are well documented.
1. The belt drive howls like mad and wears out after a few days of riding. I've got to upgrade to a better system, and hoping that LightningRod's new wider belt will do the trick! SpinningMagnets suggested that I file down the teeth of the motor gear to lengthen the life of the belt. I haven't done this yet.
2. The idle pulley on the secondary side constantly "falls off" meaning that I have to get off the bike and re-thread the drive chain. Again, maybe the LightningRods adjustable sheets will help here, by eliminating the pulley all together? On another thread I see that someone replaced the red idle gear with a plastic wheel with sides that is likely to have the chain fall off. Are there other solutions?
3. I have to add a throttle cutoff when the hydraulic brakes are activated. This will be wired to the Cycle Analyst.
4. I would like to replace the stock GNG throttle with a thumb unit.
Other than that, I couldn't be happier with the bike!
