Daily ELDBLOG (Electric Dirt Bike Log)

I turned down the Current to 50% and left the top speed at 100%.

Off the line acceleration suffers, but there is no other difference. I will check out whether it improves my "GAS MILEAGE." :-) It should.

Setback, repair, and lessons learned

I set out this morning to log my commute. I started logging one event per second - took about a minute to get on the bike and going - headed out of the driveway and as I turned left, wham! full "throttle!" The bike took off FAST - but the brakes won. There was smoke and the main fuse blew (goodbye 40 bucks :-( ) I immediately began cursing the controller and throttle. However, since I was logging, I saw something else was to blame when I reviewed the output at lunchtime (had to drive my car to work.) Something south of the controller must have shorted to ground. That thought was correct - When I got home tonight, I found that the inexpensive #4 cable had welded itself to the frame of the bike through the insulation. OUCH! I have encased all wires in conduit and have put a fuse on just about every wire going anywhere on the bike :-) In the graph of the data you can see me starting out - moving in the driveway - coasting into the street and then all Hell breaks loose as I ease onto the throttle. I let off the throttle when I felt it take off, and you see the throttle position is correct at zero as is what the controller thinks is the current. The telltale sign is the battery voltage which went all the way down to 8.7 before the fuse blew. This says that the current was not going through the controller - but somewhere else. The culprit is the crappy insulation on the #4 cables coupled with the fact that I'm using a 3 wire 48 - to 12 v DC - to DC converter that forces me to ground the 48v system to the frame of the bike due to the 12 volt system being negative ground. Unfortunately, the negative side of the 48 volt system is the one that goes through the controller - the positive is directly connected to the motor - therefore anything "going to ground" from the negative side of the house past the controller is going to send upwards of 500AMPs to the motor. 3 lessons learned - 1.) I didn't go for the kill switch, I reached for the clutch which no longer exists - therefore I may install a spring loaded clutch that kills a seperate contactor that kills all onboard power - 2.) I had a big, thick, unfused ground strap from the battery negative to the frame of the bike. I have installed a 10AMP fuse so that if anything more than the onboard lights, horn, blinkers draw through that wire, it will open the fuse. 3.) The cheap wire was pierced by rubbing on some sharp welds and a bolt - I have encased it all in conduit.

Log of a rainy night run

After a bit of a false start tonight that included a lot of smoke from a wimpy ground wire(replaced with a number 6 wire,) here is a night run around the neighborhood - about 25mph... then to a stopsign... then 35mph for a bit... then turned around and headed back (it had started to rain.) I'll log some more tomorrow.

I have traveled over 120 miles now as an electric - that used to take 2 gallons of gas at about 2.55 a gallon - I have charged 5 times from stored solar and 5 times from the grid at 14ish cents or less per charge - so I've saved almost 2 bucks over the last two weeks :-) Haven't polluted much either!!!

48 volt connector added

I decided to just stick with one 48 volt connector through the gas cap - will put dongled rubber dust cap over it when not in use. Wired it up with some beefy wire and 2 inline 20AMP fuses.

5 days on the electric Dirtbike makes one WEEK! :-)

I'm averaging about 13.5 - 14 miles per charge now. Pretty happy with it. I would like to tweak something - but it is running perfectly. I will add data, A/C , and a 3 pin charging jack inside the gas schnozzle under the cap this weekend.

Mileage may vary

The Maiden Commute was just about exactly 10 miles and it was limping by the time I got home. Voltage when I got home was 11.7x4 = 46.8.

I had shut off the charger last night prematurely when I measured an inflated surface charge on the batteries.

I will let it charge tonight until it shuts off and make sure they get totally filled up this time.

Maiden Voyage

Pretty good camera work for an 11 year old. :-)

DONE!!!

Man... it is PERFECT. Perfect gear ratio - 27ish mile range (-edit- bike ran out of steam tonight after about exactly half that range - putting a full charge on it tonight to determine the range tomorrow - but I'm guessing it is gonna be closer to 18 - 20 miles between charges)... PERFECT in every respect.

I am done except for some prettymaker.

Top Speed - 50MPH
Range - 27Mi.
Weight - gained 20 lbs or less - raised the center of gravity a couple inches - but It was low anyway.
cost - 1350 bucks plus 700 for initial purchase of bike
Man... it worked out EXACTLY like it did in my head!
Awesomeness - very awesome

I only shocked the shit out of myself 3 times and burned myself with a soldering iron once - and created one very small fire which did no damage. :-)

I can't wait to make a LIFEP04 battery bundle next year!!

It is exactly like it was in my head.

Nearing Completion

Cut the tank and bolted in the controller - the 2AMP charger will also live in the tank, with the contactor just below the tank - in the space where the tank would have extended. bolted the batteries together with metal straps, and added a 1/4 inch motor mount / tensioner for added stability. Pictures are - Cutting the tank, Motor mount, and contactor installation. This weekend, I'll shave another 1/2 inch off of the contactor side of the tank (it touches the contactor) and buy some longer cables to reach the motor (I'm going with #6 - although #4 would probably be better for off roading), and wire up the rest of the sucker and take a spin :-)

Cleaned, painted, and secured the battery tray

Not much progress last night - I cleaned and painted the battery tray - and secured it - I can stand on it - should be good enough for commuting - the batteries still touch the shock mount - so I sandwiched some 16 ga. steel in there as a buffer so it doesn't scratch the battery cases. I'll wire it up tonight - and locate the controller. I need to grab a 5 amp inline fuse and a 6 amp diode for the key switch mechanism.

Installed the Magura Twist Grip(s), rewelded the battery tray, and decided to cut the tank

I have been agonizing over whether to cut the gas tank on the SP and render it unreversible (without a purchase on Ebay) - screw it, it is a perfect place to keep the electronics... so it will go under the knife. I also gave the battery tray the fling test and it broke apart - turned up the juice and rewelded it while getting eaten by mosquitos. The maiden voyage has been delayed - maybe later in the week.

Programmed the Alltrax AXE 4844 tonight

I scrounged some DB-9 RS-232 cables and adapters at work today (thanks, guys!) and was able to talk to the controller - pretty awesome!!! Two thoughts I had were (and have had) are 1.) the controller protects from turning on the juice when the throttle is nailed... but what if the 0 - 5k throttle comes open while you're traveling down the road? guess it would go 100% and you would just have to hit the red button - or turn off the key at that point. 2.) My other fear is having the motor lock up electrically. Since you can't set up a permanent magnet motor to "plug" or engine brake - maybe that is not a concern - I'll do more research.

Welded Battery Tray

I welded the battery tray last night and fit it in there - man... it is a tight fit. I had to put a piece of 16 ga sheet metal in there as the shock was digging into the back 2 batteries. This rig should be good for commuting - but since the batteries weigh 96 lbs, I'll need to reinforce it when we go to BIG ROCK again!

Made a motor mount, and rearranged the Batteries

I took the day off work today and made hay on the bike...



The stopcock is pushing down on the batteries and causing the tank to ride up in this picture - apart from that - the bike will look like this when done.



The motor mount consists of a 1/4 x 2 in piece of steel bolted to two of the mounting holes on the face of the motor - the other end of the bar ties into the long bolt going through both sides of the trailing arm - I've put a piece of 3/4 in tubing over the bolt and sandwiched in the metal bar so it is very rigid. I will weld a strut going straight down from the engine to keep it from tilting up when the juice is applied. I bound the engine to the swingarm fulcrum with a tie down ratchet to minimize engine movement - may keep that - may go with a metal band. Just need to make battery trays now and connect the twist grip and controller (and contactor, diode and resistor,) and AWAY I GO. WORK TO RIDE... RIDE TO WORK!!!

The motor mount looks like this...


Also did my first electric burnout (12v / 864ish RPM)

Latest Mockup

I added some 3/4 in steel tubing for the bottom of the frame and to serve as a motor mount. Turned out pretty well.

Making a motor mount

This is the first draft at a 1/4 inch motor mount for an Etek clone I made today.

Mockup II Electric boogaloo

So much for my previous mockup - the bike shrank or something - so I had to reconfigure the batteries into an ugly configuration. Oh, well. I'll put some prettymaker over it later and make it look nicer.

The Etek clone fits into the nook created by my removing the long anchor bolt that used to go through part of the engine case - I've replace that bolt with 2 others to hold the swing arms. I am finding that fabricating a mount is more difficult than I had thought it would be. if I attach a faceplate type of mount on the shaft side - that is not enough to hold the thing in place - maybe when I bolt in the bottom sissy bars that tie in the front bottom of the frame with the area of the swing arm mounts, I can mount the motor to that. Maybe I need to visit a scrapyard and just get a bunch of material to work with and something will speak to me.