The Perm 132 is a little to pricey for me...Jozzer wrote:If you can afford it consider a perm 132, very well made motor:)
You'll want around 1500watt hour battery pack to get your 15-20 miles range, thats 30AH at 48v, or 20AH @ 72v. Again, if you can afford it, get a lifepo4 pack (a123 or LifeBatts), youll get 95% of the rated AH.
If I'm going to have to run 72 volts, lithium batteries are going to be insane... I saw 3v lithium batteries for 100 bucks a piece, that's a little much.lazarus2405 wrote:I don't know your budget, but I'll recommend at least looking at your options in lithium. What are Ping's packs, ~$0.75/Wh? Expensive, compared to lead, but I'm worried you'll have a heavy cycle with not much range. Then again, I have no idea how much lead you can get into a sportsbike.
It is my understanding that the Etek is a much better-made motor than the Mars, and that despite being brushed it is in fact more efficient than the Mars. Can anyone back that up?
kbarrett wrote:Yea... you are going to want to go to Lithium Iron Phosphate ASAP ... but you can fake it for now with lead acid.
Another option might be a trailer with three big RV batteries in series ... that will get you there cheap until you can build a proper cell with Lifebatts or A123s.
Ping packs are great for bicycles ... but the prismatics just don't put out enough amps to run a motorcycle properly.
The weight will also be lower with an empty gas tank and no battery in stock location.lazarus2405 wrote:Well, I'll point out that weight isn't the only benefit of lithium over lead, but your plan looks good.
Puting the weight in perspective with the engine/tranny really helps. It should handle fine.
Run those batts hard; beat them up. When they die out in a few years, you'll be working on your next build. The lithium then won't just be cheaper, but safer, more energy dense, have a longer lifespan, and have higher discharge rates. That's based on what's happened with them in the last few years. With even more R&D going into battery technology now, I think it's fair to expect at least the same in the mid future.
Back to the motor. I'd stick with the Etek and as high of power brushed controller you can get. It'll be harder to feed a Mars as much juice. All things considered, performance should be more or less similar, and the controller options might make more of a difference.
You will want to consider regenerative brakking. On bikes it's more or less a curiosity, but with a cycle you'll have a lot more energy stored in the greater mass, and loose less of it because of the far better aerodymics.
fechter wrote:Safety note:
Be sure to include a main contactor that can completely disconnect the batteries in the event of a controller short. This is particularly important for brushed motors since a controller short can cause full output to the motor. The cutoff switch should be in a easy-to-reach position, like the kill switch on a regular motorcycle.