DIY Idea...
 

Question for ebike DIYers. I would really like to try an ebike, however i have extremely limited funds. I came across a battery powered pole chainsaw for free. Has anybody heard of trying to adapt one of these into an e bike application?

Unlikely to work particularly well.
Ebike batteries have far greater capacity than hand tools.
And I wonder about the torque the chainsaw can produce.
Chainsaw chains engage in a rather different manner than bike chains.
So there's no obvious, easy conversion.

Check endless sphere and or other sites. I've seen a contraption or two that seemed viable, but not for me.

my biggest expense is battery (followed by a $79 motor and some misc parts that cost less than $10). Ebike batteries need a lot of power and head room. Hard to save money there...

Sure, it's been done. Mostly by people who shortly afterwards did something else.

Battery is BY FAR the most significant expense. Look into recycling used power tool packs. Lots of time and work but these can be used to leverage limited funds.

Simple friction drives are do-able but have a LOT of limitations and most users abandon them fairly soon. Hub motors are cheap and very reliable.

It's probably easier to get a $99 kit like this one, if you don't have good metal working facilities. I think you might want to replicate this arrangement, which uses a free wheel that screws into a single speed sprocket. If you can get that part, then add a chain and some metal brackets. Motor gear might work. Zoom zoom?


http://farm4.static.flickr.com/3189/...f3ea8b46_b.jpg

For $180, I can get a nice 500W geared motor with wheel and electronics off ebay. I run mine on a $280 36V 10AH battery from China, but have also run it on my Ryobi Weedwhacker battery, which is 36V and about 2 AH. In fact, I ran it for 11 miles yesterday at 14 mph on pedal assist before I used up all the power. For throttle only, I'd be lucky to get 4 miles at that speed.

what is the chainsaw's Ah? i saw one for a weedeatter that was 2Ah at 48 volts that is about 100 watts
bike motors are usually 250 watts and up

Some very inventive people have done cool stuff on youtube. Just a suggestion to check there if you haven't yet.

If I may be so bold - what is your idea of a finished project going to be, do, accomplish?
Is it a toy to just ride up and down the street in front of your house?
Is it going to take you to work? or replace other transportation?
Is it going to save you something? Time? Money? Stress?

If you don't have answers to these ??'s then before you spend anything - figure out what you are spending towards.

Since you say money is tight - spend it right.

Hope it helps.