Wednesday, December 18, 2013

48 tooth Update

I got a little greedy and went for the gold…. changed out both pulleys to 48 tooth. Ended up with a computed top speed of close to 40 mph. Had a few technical issues though and ended up with gearing for a 32 mph top speed. This motor makes serious power and had me grinning big time.

Friday, December 13, 2013

It's Alive

I'm  waiting on the 48 tooth pulley but went ahead and ran it a bit with 20 to 72 primary... 18 to 72 intermediate... and 14 to 52 final. I got 15 mph just running it with no load on the work bench. It would appear that the 245 KV rating is pretty close to real world. Projected speed should have been 14 mph... I reckon the extra speed is a result of battery voltage being more like 48 as opposed to 44. I should be able to get this bolted together sufficiently for a road test Sunday... its supposed to be sunny. Swapping out the 72 tooth intermediate for the 48 should give me a top speed of 22.... and hopefully decent hill climbing. As it is.... should have plenty of grunt with the current gearing for Sunday.

Thursday, December 5, 2013

New Wheel Finally Ready

Finally got my new wheel... I didn't originally plan to use the BB shell in the drive system but looking like I have no choice. Probably going to require some frame surgery to allow for the motor and primary reduction components.

Monday, December 2, 2013

Trike Drives

I've been making some of the parts I'll need but still waiting of my new rear wheel with the disc brake hub. The design is still somewhat up in the air  and somewhat complicated by the fact that the trike has a rear suspension. This trike was mostly a low buck hack so I would have two trikes in case I wanted to ride with someone else. This was my second home built trike... the first weighed a ton and the front wheels were originally moped wheels with internal brakes. They were on an ultralight that I had long ago.

The motor is a 2750 watt 1.60 gas equivalent... I found a couple of the white shaft housings at work... they had 16 mm shaft with bronze bearing. The black shaft housing has a 1/2 inch shaft also has bronze bearings.

I have not bored the metric adapter yet. It was mostly to see if I could cut a thread that would fit the 30mm x 1mm freewheel.                                                                                                                                            

Trying to fit an an 1.375 freewheel adapter into the bottom bracket shell. Not sure what thread it is but it is a tight fit that I didn't want to force.

Made this adapter to fit a 52 tooth chain ring to the disc brake mount. This ring was less than 10 bucks and was intended for the old 1 piece style crank arm that is still used on some bikes. this is a junker rim that had a disc brake hub on it. I'm using it to line up drive train until I get my new wheel.... which should be in the next day or two.

Monday, November 25, 2013

Couldn't Wait

I'm still waiting on some parts to complete my electrick trike conversion but couldn't stand it any longer and hooked it up yesterday in the friction drive mode. I had tried this a little with a brushless drive that was too small and it worked at low speed but was slipping a lot. I added more bungees and then when I tried to roll on throttle it sounded like the drive was out of sync with the motor. I tried it at several different speeds with the same effect... finally added a bunch of throttle and it promptly smoked the drive. Luckily didnt smoke the battery... it had melted one of the power solder connections to the drive which saved the battery. 

After reading some posts about others using a friction drive arrangement I decided to try it again. I didn't smoke anything this time but I did manage to grind a little off the OD of the tire. I could have added more bungees but thought I was already pushing the limit on how much of a side load I wanted to have that far out from the bearings.

I got the new hub and rim and I've made an adapter to mount a chain ring on the brake rotor mount. Still waiting for spokes for the wheel so tried this one more would do about 17 miles an hour on level ground. It is a 245 KV motor and I was running it on 22 volts.I don't believe I'll have any problem getting 25+  miles an hour out of it on 44 volts.

Monday, November 11, 2013

In Flight Adjustment Take 2

I was hoping to use a belt drive from the motor reduction to the rear wheel.... but it is pretty much a custom piece and pretty pricey and the source for this piece has been a bit difficult to communicate with.

So for a number of reasons... primarily price and easy availability I've decided on a little different route. Instead of a one way bearing and belt drive... I'll be using a BMX freewheel in reverse mode... driving instead of driven... and a crank chain wheel on the rear wheel. It is is going to require a new rear wheel with a mountain bike type hub with provision for a disc brake rotor mount.

I created a spread sheet to analyze the gear ratios needed to end up with a target speed of about 30 mph. My home built trike has a 24 inch rear wheel so it requires a little more reduction in the drive train than would a 20 inch rear wheel. Still debating somewhat..... whether to use an existing motor that I have.... or bite the bullet and go for one of the Astro motors.       

Some parts will be the same either way but going to try to keep it as simple as possible. A 44 tooth chain wheel on the rear wheel.... bored and drilled to fit the brake rotor mounting holes. A 13 tooth BMX freewheel driving that. It will require a  a custom piece to mount on to a 16 mm jack shaft. On the other end of that shaft will be a 5mm HTD belt drive pulley and a smaller pulley on the motor to complete the drive train.                                                                                                  

Wednesday, November 6, 2013

An Inflight Adjustment

Welll after riding Outriders Cadillac I've decided to make a few course corrections. I'm planning to follow their lead on a few things... a parallel belt drive on the opposite side from the normal bike chain drive... a one way bearing to allow the bike to freewheel when not on the power.  On the control side.... no power to the motor until the bike is moving and limiting max power to extend run time and reduce drive train loads.

motor, drive pulleys, plain steel jack shaft running in bronze bearings

Monday, October 28, 2013

Mid Drive

I've just ordered some parts to build a mid drive similar to this. The primary drive will be approximately 4 to 1 with a MTD belt 15 mm wide. I found the primary drive parts here B&B Manufacturing. They had an online belt length calculator for specifying pulley sizes and belt lengths.

Big Power Small Package

These motors make a ton of power for their size.. this one is a 295 KV motor rated at about 2000 watts. For starters I'm using a 22 volt 5000 ma battery mainly because I already had one. I've ordered a drive that's good for 100 amps @ 44 volts and a 245 KV motor that's rated at 2700 watts

Friction Drive

I put this RC airplane brushless motor on my home built trike some time ago. It's just a friction drive on the rear tire... the ultimate in low buck kiss inspired technology. I didnt have a brushless drive with enough capacity for the motor so I just ordered a  brushless drive for it and will probably try it like this.
The the goal is to convert it to a mid drive arrangement inspired by a pic a story on the the electric bikes web site as posted in the post below.

Recumbents Trikes at the Shade Tree

I have been a long time fan of recumbent trikes but they really have not caught on very well... at least not around where I live. The last time I went by TTR bikes... where I bought a Catrike a few years ago... they didn't even have any recumbent trikes in the store... mostly just two wheeled recumbents.

I just ran across a website a few days ago about Electric Bikes. Lots of great info there for DIY electric conversion and just about anything else you  might be interested in concerning electric bikes including one story about an electric trike built in North Carolina that won the Pikes Peaks hill climb for electric bikes. They blew away the previous record.