E-Mountainbike Project
 

Hey guys!

My new project.

I'm converting my 2008 Giant Rincon 26" mountainbike with a 18" frame to electric, and am going to have all components mounted on the bike rack. Plan is tomorrow I'm going to go find or pick up some angle al or steel and make a motor/esc mount, using the existing mounting holes for the mount. Electronics are a CIM FIRST brushed robotics motor, a 24v e-scooter ESC and 24v 10-12ah lead acid batteries. I have 3 12v 10ah? batteries from my old e-scooter, hopefully they're still good and I can use them in this project. My design is simple, going to buy a 16:1 reduction gearbox for the CIM motor from ben, and then have a 15t sprocket with a chain that runs down to the 32t rear wheel sprocket on my gear cluster. Works out to about 24mph. I'm uploading a test video of the electronics with my 6s neu pack, and will get pics when that is finished uploading. This project *should* be finished a lot quicker than my gas pocketbike, because there's a lot less to do.

Update!

Bought Ben's 16:1 reduction gearbox for the CIM motor
Ordered a 14t 1/2" bore #40 sprocket from mcmaster-carr

Oh, here's that video I was talking about:
http://www.youtube.com/watch?v=rAUG-FBU3oc

And some pics for you.

http://i160.photobucket.com/albums/t...1250114262.jpg

http://i160.photobucket.com/albums/t...1250114263.jpg

http://i160.photobucket.com/albums/t...1250114264.jpg

Also guys, I'm leaving tomorrow on a trip until the 20th, so I can't post any updates, but I will be able to be online, possibly.

Well, I'm back from my trip. Got my gearbox and sprocket in, but the sprocket will need some serious modding to mesh with the bicycle chain. I need to go to my LHS tomorrow to pick up some alum for the "chassis", some bolts to mount the motor and such, some sheet metal to bend up for a battery tray, and have to order batteries as well.

Some pics for you:

http://i160.photobucket.com/albums/t...1250817564.jpg

Sweet project. Where are you getting your gears from?

Still haven't seen a vid of the pocketbike..:whip: Is it still alive? :neutral:

Got that gear from mcmaster, but other ones I bought at an industrial salvage place. Pocketbike is dead for the time being, I let by friend ride it, and he crashed into his mom, (lol) but put his leg in such a way that it made the front chain pop off. There's no way to take the primary jackshaft sprocket off, and you can't put the chain over the gears at all, without moving them. So, we had to take the clutch off. To do this you have to lock the motor, usually by sticking a rod in the flywheel to stop the engine from rotating. I told him to do that, and somehow the idiot managed to pop the recoil spring out. :no:... Anyway- I'm gonna go pick it up tomorrow and see if I can fix it...

Got a battery!

Well, i didn't buy anything but I found this. It's a 18V 7ah battery, not ideal as I'd planned a 24v 12ah setup, but before I get paid, this will do. I just have to go to the LHS and pick up some deans, then I can charge this thing up and try 'er out. Q: Does anyone know if you're supposed to discharge lead acid batteries before charge, or just charge them? If you're supposed to discharge them, to what v/cell should I go to?

http://i160.photobucket.com/albums/t...1251215585.jpg

Hey I have one of those batteries!:lol: How are you going to charge it? I tried an 18v power supply before I modded the bike and I got a spark and I think a dead power supply. :angel:

Oh no you di'int! :lol:
What do you want for that battery? 18v 14ah would be awesome... I have a LA setting on my 1210i, gonna use that.

A bit of unfortunate news. The 18v battery I have won't work with my hyperion, because it only handles 12v Pb batteries, so I'm gonna buy the 12v 12ah items I was going to earlier...

the turnigy accucel-6 charger can handle up to 20v Pb batteries and it is only $35. i have one and i can vouch for it. it has the same charge accuracy as a hyperion 6s lipo charger. i have used my accucel to charge 12v Pb batteries and have had no problems.

Thanks for the suggestion, but I can get new batteries for $45, for a 24v 12ah setup. If I get this charger, I still have to spend $20 on the other battery for a 18v 14ah setup. This is geared for ~25mph on a 24v setup, and it seems like 18v would be too slow, so I'll just get that batteries, because I don't even know if the battery I have now works, so it could be a waste of $35.

Update. Not big, but it's something I needed to do that got done, finally.

Got the screws I needed to mate the GB to the motor. 10/32 3/4" cap head. It's amazing that something that costs 59 cents can stop an entire project for nearly a month...

http://i160.photobucket.com/albums/t...1252875896.jpg

Plate mounted to motor. Had to take those washers off, but you get the idea.

http://i160.photobucket.com/albums/t...1252875897.jpg

All assembled.

http://i160.photobucket.com/albums/t...1252875899.jpg

I also test-fitted everything (minus batteries, as I don't have them yet) to the rack, and they fit nicely.

Typically you charge a Pb battery to 2.4V per cell so a 21.6V power supply. Most 24V power supplies are adjustable into that range. All you have to do is limit the current to a point lower than the output current of the power supply.

Say you have a 24V power supply rated at 5 amps You would need a resistor rated at about 5 ohms and 120W. That's a little on the large side and a pretty high charge current. about a 1 to 1.5 amp rate is a little better for up to about 12 Ah. So you would still need 5 ohms but only about 40 watts. Basically the resistor would limit the current coming out of the power supply and keep it from tripping or just smoking.

http://www.mpja.com/prodinfo.asp?number=16008+PS

Jeff

I don't have a 24v PS though. Mine's 13.8v and 8.5a. Works fine for me, so I have no plans to upgrade it.

That was just in case you wanted to charge both batteries at the same time or if you wanted to use the 18V battery.

Jeff

I was thinking of charging them as a 12v 24ah setup. Would that work with my current PS?

With what you have yes, the only thing you have to worry about is that the lower the voltage on the batteries the more current they are going to draw, so it might trip the PS when you first start to charge them. The only other thing you have to worry about is charging them too fast. I think a 12 Ah battery is recommended to be charge at about 2.5 amps max, but with them in parallel that would be 5 amps. If you have an adjustable power supply (most are) you can lower the voltage and watch the current drop and then slowly increase it until you are at the 14.4V value. I have been using a regular car charger the maintance free kind with a couple of resistors in series with the + output.

Or I will use my 60 amp power supply and just watch the gauges set it for about 1 amp charge and when the current drops I increase the voltage till I am back to 1 amp then repeat until I am at 14.4.

The maintance free charger is the easiest way since it will only go to 14.4V

You could get a 24V power supply and charge them in series and not have to remove the batteries and reconnect them.

Cheaper ones:

http://www.mpja.com/prodinfo.asp?number=16854+PS

http://www.mpja.com/prodinfo.asp?number=16855+PS

Jeff

I use a car battery charger to charge my pbs.

What kind, brand or model?

Jeff

i have a mrc super brain 989 i use to charge all my stuff including pbs. i even used it to charge my real car battery when i was on a camping trip and left my lights on, and i was the only one there. im just lucky my cabin has an outlet. it will charge up to 5cells in lead acid mode, i believe each cell is 6v if i remeber right i dont use that setting much at all

2V per cell on Pb batteries.

Jeff

Ok guys, there's been a slight change in plans. Well, first off- I got my batteries! Woot! They're from my old e-scooter, 3 12v 12ah, but they work great. So here's the plan: It's gonna be the same motor and ESC, and still 24v even though I have 36v worth of batteries. I'm gonna ditch the sprocket I bought and the idea of running a chain down to the rear gear cluster. When I grabbed the packs, I also got the rear sprocket and freewheel. It's a 80t #25 sprocket, and a crappy but working freewheel. So what I'm going to do is mount the sprocket/freewheel on my crank, a much better plan IMO. All I need to make is essentially a large washer, a spacer to adapt the crank OD to the freewheel ID- not hard at all. I'm going to order another primary sprocket from mcmaster, as well as some chain. The sprocket is a 1/2" bore #25 14t sprocket. With the gearbox and that reduction, it will match my highest pedaling speed- about 25-30mph. With the planned gearing, and my ratio from my "foot-powered" sprockets, I'm looking at exactly 25.7mph. Perfect. The ratios are 16:1 (GB), 80:14 (primary to secondary sprocket) and 16:40 (pedaling sprockets, gear up)... Some pics for you to clear it up incase my explanation is fuzzy...

Here's the layout (old sprocket not being used still installed)

http://i160.photobucket.com/albums/t...1253672013.jpg

80t #25 sprocket

http://i160.photobucket.com/albums/t...1253672015.jpg

Where that sprocket is going

http://i160.photobucket.com/albums/t...1253672016.jpg

Are you going to support the end of the shaft of that gearbox?

Nope, but the pics make it look longer than it is, I'll probably just cut off the excess.

Mini update: 14t 1/2" bore #25 sprocket and 5ft of #25 chain ordered, scheduled to arrive monday. :party:

Have you tried the 36volts worth of batteries with the 24v controller?

Jeff

I can't fit them on the bike frame or get the reduction I need to go anything less than 40mph with 36v.

Oh, Ok I thought you were going to use all 3 batteries.

Jeff

Nope. But I do have a 36v controller I might use for a different project.

You don't happen to know of cheap 36V controllers that can handle about 400Amps do you?

What's your idea of cheap?

A dolla. It's got to handle a 3 HP series wound motor (golfcart). Less than $100.

Jeff

No I don't. Sorry Jeff.

Got my new sprocket and chain in!

http://i160.photobucket.com/albums/t...1254178364.jpg

http://i160.photobucket.com/albums/t...1254178365.jpg

It's coming along nicley, are you working on the frewheel to your front gear cluster now or did you already finish that part? This was always one of the sticking points I had for adding an electric/pedal powered bike. You said the freewheel was gritty were you able to clean it?

I have always wanted to build one. When I was about 15 I saw a pair of bikes that had a engine that was strapped over the front wheel and when you wanted to run the engine you moved a lever that moved the assembly onto the tire and a friction drive roller was put in contact with the tire starting the engine, apparently they sold a few in the late 70's.

Jeff

Since my dad moved I no longer have access to the tools needed to remove the freewheel. I shipped the unit up to him and he'll take it off for me. I'm not sure when he'll get around to it, but hopefully soon.

great build , i am just lurking here since i am thinking of getting a 3 wheel adult tricycle for my dad , and this is what i was thinking of doing with it

not to hi-jack but anyone who has any thoughts are welcome to pm me , but i am thinking of a tricycle for an adult with a similar setup (or a hub in the front wheel) so to it can still be used normal when possible , thanks

Thanks eric.
Tricycle idea sounds pretty good, but why not something like a recumbent?