Quote:
Originally Posted by 99dart
NICE!! Thanks for posting. I have been watching the local "Craigslist" for nice older bikes. I'm just unsure of the wheel kit. What brand (or are they pretty much the same) & voltage/watt combination to go with. I have been building battery packs since the 80's when I raced radio control off road cars. So, I have been tearing apart my old laptop batteries and using the 18650's in an old drill and electric screw driver. It's fun to mess with!  |
Pat, laptop cells are built for 4 hour+ discharge rates and won't work well for e bike use unless you are building a huge battery (80+miles). Cells from tool batteries or cells with 10+ amp continuous ratings (30amps for 3 in parallel) is what's needed.
36v500w kits are adequate for single bikes, even tandems, if you have good batteries and contribute some muscle (especially on hills). If you use proper size wires and good connections (soldered) you'll see nearly 1000 watts peak. I've bought lot's of 26" and 700c kits from Ebikling.com and recommend him, but he has had no kit inventory for months. My next buy will be from one of the Ebay sellers. Typically they only sell 26" wheel kits, but that's fine. I would suggest one with a controller that has 2 power levels. A simple on/off switch on the 2 blue (usually) wire changes between full power to 25mph and power only to 20mph. Sometime they call it "legal" mode. 25mph+ is fun but the battery range is reduced. Remember air resistance is the only important force to overcome and it increases with the square of speed.
I like to keep the build simple and don't install the PAS (pedal assist); only throttle. I prefer thumb throttle to twist. I don't install the brake cutoff connections unless I have to use a twist throttle (You often can't help turning the twist throttle grabbing the brakes). You will never use or need the 2 smaller front chain rings on an e bike. The left shifter can go and that a good place for the throttle. Road bikes usually have 53/11 top gear which allows a reasonable pedal cadence at 25mph. High end mountain bikes often have an 11 in the rear but will likely need a larger front chain ring or so you don't spin out and not be able to contribute power. If the bike frame is AL you probably need suspension . A rigid Cromo steel bike is OK but a large 2.15-2.25" front tire to handle 25mph pot holes is a must. Never use an aluminum front fork with front drive. The torque of these motors is huge and it is all transferred to the 10mm flats on the 14mm dia. axles. Use or build steel torque arms to keep the axles from spinning and eating out you fork's axle mounts.
48v1000w kits go faster (28mph) but consume battery power faster. The hub motors are the same so just changing the controller(~$35) will change power rating. Many controller (like ebikling's) have an external display that programs the controller for various voltages. Since I use tool batteries, 36V(2s) and 54v(3s) are my only choices. It turns out 54v works find with all the 48v controllers I have tried.
For you first build, put everything on the bike and test it. You can then go back and shorten unnecessary long cables. I remove connectors that are not needed with solder and sealed connections. I replace the connectors are used (like controller to hub) with quality waterproof one.
Good luck. It's fun. The technology is amazing and it will likely change your life and health.
Thor Forums
