4 ms·

Not bad. Id rather build it myself with a kit like the one you linked. How reliable are these kits?

bigiain 10y ago
That one's 2 years old now (just over), and the power system is now onto it's second cheapo mountain bike (that one had the chain slip off the rear sprockets when the gears were badly adjusted, which damaged the spokes, which later broke. It ended up being less hassle buying a new bike than repairing the wheel). I do a 16km round trip on it 3 times a week or so (less during winter, it's fun to ride, but _way_ less fun in the rain). I guess I should mention you'll also need a charger capable of charging your chosen battery (I already had two, so I don't factor in the cost of that - you'd be looking at ~$50 or so at the bottom end there...)
- asimuvPR 10y ago
  Thanks a lot. The info is very useful. I shall make this my next diy project. :)
- Animats 10y ago
  E-bike fires from bad lithium batteries or bad chargers are a problem. Same problem as hoverboards. Boosted Skateboards went with LiFePO4 batteries, which have lower energy density and cost more, but don't catch fire or blow up, even if punctured with a nail. Some e-bikes use LiFeP04 chemistry, some use LiPo, some use Li-ion. Go with LiFePO4 and look for UL approval on the charger. Pedego had to recall 5,000 e-bikes after battery fires.[1] There have been some major fires at e-bike shops. [1] http://www.cpsc.gov/en/Recalls/2015/Pedego-Recalls-Electric-Bicycle-Batteries/ http://www.cpsc.gov/en/Recalls/2015/Pedego-Recalls-Electric-...
  - bigiain 10y ago
    Sure - I've flown these kinds of batteries into the ground from great heights doing dumb stuff with drones/quadcopters/modelaircraft - and abused them pretty badly while charging. I've occasionally had Galaxy Tab 7 style "incidents", and take suitable precautions given my experience with the risks. The 7 cell 5800mAHr batteries I use on the bike are the biggest and most dangerous ones I use - and I do treat them with respect. I charge them in the middle of the concrete floor of my garage, inside a besser block, at least 1.5m from anything valuable or flammable. I dispose of them if they go puffy (I've sent two off the the e-waste/battery-recycling in two years - one of them I knew I'd let run down way too far when using it elsewhere, down under 19V which the bike's controller wouldn't ever do (it cuts out at 22V) and it never managed a good charge again, the other I'd been quick charging occasionally (although not really fast enough to explain the shortened lifespan - I can only _just_ hit 2C charge rates with my charger, the battery _should_ be good up to 5C really...)) If you don't know (or want to learn) the risks, or if you're less risk averse (or less able to mitigate the risks due to not having suitable space to let a lipo fire burn itself out) LiFePO4 is a slightly heavier but much safer battery chemistry. I _almost_ got hold of a bunch of cells from a crashed Tesla's battery pack a while back - they'd make a nice ebike power supply. If I can get my hands of enough of them at a reasonable price, I'm planning on electrifying one of my motorcycles with 30+KW of electric power...
    - Animats 10y ago
      Yes, if you take hazardous-material precautions you can handle hazardous materials. I do machine shop work; I get that. But people are going to bring their e-bikes to the office and charge them indoors. "Occasionally catches on fire" is unacceptable for that usage.

That one's 2 years old now (just over), and the power system is now onto it's second cheapo mountain bike (that one had the chain slip off the rear sprockets when the gears were badly adjusted, which damaged the spokes, which later broke. It ended up being less hassle buying a new bike than repairing the wheel). I do a 16km round trip on it 3 times a week or so (less during winter, it's fun to ride, but _way_ less fun in the rain). I guess I should mention you'll also need a charger capable of charging your chosen battery (I already had two, so I don't factor in the cost of that - you'd be looking at ~$50 or so at the bottom end there...)

asimuvPR 10y ago
Thanks a lot. The info is very useful. I shall make this my next diy project. :)
Animats 10y ago
E-bike fires from bad lithium batteries or bad chargers are a problem. Same problem as hoverboards. Boosted Skateboards went with LiFePO4 batteries, which have lower energy density and cost more, but don't catch fire or blow up, even if punctured with a nail. Some e-bikes use LiFeP04 chemistry, some use LiPo, some use Li-ion. Go with LiFePO4 and look for UL approval on the charger. Pedego had to recall 5,000 e-bikes after battery fires.[1] There have been some major fires at e-bike shops. [1] http://www.cpsc.gov/en/Recalls/2015/Pedego-Recalls-Electric-Bicycle-Batteries/ http://www.cpsc.gov/en/Recalls/2015/Pedego-Recalls-Electric-...
- bigiain 10y ago
  Sure - I've flown these kinds of batteries into the ground from great heights doing dumb stuff with drones/quadcopters/modelaircraft - and abused them pretty badly while charging. I've occasionally had Galaxy Tab 7 style "incidents", and take suitable precautions given my experience with the risks. The 7 cell 5800mAHr batteries I use on the bike are the biggest and most dangerous ones I use - and I do treat them with respect. I charge them in the middle of the concrete floor of my garage, inside a besser block, at least 1.5m from anything valuable or flammable. I dispose of them if they go puffy (I've sent two off the the e-waste/battery-recycling in two years - one of them I knew I'd let run down way too far when using it elsewhere, down under 19V which the bike's controller wouldn't ever do (it cuts out at 22V) and it never managed a good charge again, the other I'd been quick charging occasionally (although not really fast enough to explain the shortened lifespan - I can only _just_ hit 2C charge rates with my charger, the battery _should_ be good up to 5C really...)) If you don't know (or want to learn) the risks, or if you're less risk averse (or less able to mitigate the risks due to not having suitable space to let a lipo fire burn itself out) LiFePO4 is a slightly heavier but much safer battery chemistry. I _almost_ got hold of a bunch of cells from a crashed Tesla's battery pack a while back - they'd make a nice ebike power supply. If I can get my hands of enough of them at a reasonable price, I'm planning on electrifying one of my motorcycles with 30+KW of electric power...
  - Animats 10y ago
    Yes, if you take hazardous-material precautions you can handle hazardous materials. I do machine shop work; I get that. But people are going to bring their e-bikes to the office and charge them indoors. "Occasionally catches on fire" is unacceptable for that usage.