E-Mountainbike Project

[BL_RV0]

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.

[BL_RV0]

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.

[BL_RV0]

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.

[BL_RV0]

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:

[Metallover]

Sweet project. Where are you getting your gears from?

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

[BL_RV0]

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. ... Anyway- I'm gonna go pick it up tomorrow and see if I can fix it...

[BL_RV0]

[BL_RV0]

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?

[Metallover]

Hey I have one of those batteries! 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.

[BL_RV0]

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

[BL_RV0]

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...

[scarletboa]

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.

[BL_RV0]

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.

[BL_RV0]

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...



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



All assembled.



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

[J57ltr]

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