Electric Motorcycle conversion

[bennelson]

Hey Daox,

Yeah, maybe we should have you come out sometime and take a look at the bike and see what it would take to bend/weld another battery in there.

[MetroMPG]

Originally Posted by bennelson

No I havent' checked the brushes lately. I will have to do that in the spring before I get riding again.

One eBay ETEK seller reported that the motor ultimately didn't do well in the golf cart segment for that reason: brush maintenance (and motor damage where inspection was neglected). Very low maintenance is supposed to be one of the selling points of electric motors, after all.

My favourite ETEK application is still the electric 5th wheel on a Honda Insight.

[bennelson]

Here is some infor on the DC/DC converter I am using.

It's an Artesyn BXB100-48S12FLT.

If you scroll back up this thread to the photos I posted, it's the little black rectange in the middle of the piece of plywood. That was when I just had it mounted up for testing.

I bought it on Ebay. Price was $10. Seemed like a good deal, so I bought 2, in case I fried one while tinkering with it, or for use on another vehicle.

The fine print on the side lists it as 36-75V in, and 12V 8.3A output.

So, it looks like it's a 100 watt converter. I have heard that headlights are about 55 watts, so it's enough to run the headlight and taillight and brakelight. I have been running a 36 volt system and no accessory battery, the lights and all run straight off the power converter.

The only problem I have had so far is that after a long ride, my system voltage can drop to 33 volts under load - Going up big hills, or pulling away from a stop too fast. This converter stops working at 33V or under. It was only a problem the one time, coming back home at night on a relatively long ride.

If I fit another main battery in my cycle to raise system voltage to 48V, this would no longer be a problem at all. Otherwise I think I could add a small battery to run the lights from and have the dc converter top off the battery.

The converter outputs 12.5 volts. I know that's not enough for charging a 12V battery. There are a few pins on the converter that appear to be for adding a pot that can change the output voltage. I think I could tinker with it and make it output a higher voltage for charging.

I had NO documentation for the DC/DC converter. It took me a while to figure out which pins I had to connect to what to make it work. Besides the obvious Vin and Vout, it also had RC, CASE, +SEN, Vadj, and -SEN pins on it.

I have a switch on my control panel that turns the DC/DC converter on and off. It is totally seperate from the propulsion system, so the motor can be safety'ed off, but I can still turn the lights on or use the horn.

Right now, there is no key for the bike other than the big red emergency disconnect. If the cycle is parked, there is nothing stopping a person from turning on my lights and draining the batteries.

I plan on eventually adding a keyed electric switch that will control a contactor for the motor and power to the DC/DC converter, similar to having an ON and ACC setting in a car's ignition.

My tachometer is useless as it originally was mechanically connected to the engine. However, it does have a light for the Brake and one for OIL.

I wired my brakes up so that the the BRAKE light goes on when ever my brakelights do. I know that is how it's supposed to work, but I had to modify a few things when I moved the rear brake to a hand brake.

I wired up the OIL light to an output from the DC/DC converter. So, it's just a big ON light. When it is lit, I know the DC converter is working right, my brakelights will light up, etc.

I would like to eventually convert the tachometer into an ammeter. I think I could just pop one of the right size right into the tachometer housing. If I was really clever, I could scan the tachometer, pull it into photoshop, mess with it to make a ammeter scale, print that out and fit it into the ammeter. Then I would have an ammeter that would look "factory original".
Click on this link and scroll about two thirds down for a better example of what I am talking about:
http://www.theworkshop.ca/energy/dirt_e/3/3.htm


In some photos, the bike's gas tank is green, in others, it is white. When I got it, it was silver/primer gray.
I originally hit it will the green, just to make it a little different - yes, a GREEN vehicle.

Later, I thought I would paint the tank white, and put black spots on it like I did for the paintjob on my old Chevy/Geo Spectrum. Unfortunately, a cow-spot pattern needs a bigger area to look right at all.

I am now leaning towards a really right yellow. It would match the batteries and be highly visible, a good trait in a small, quiet vehicle. I could still paint green lightning bolts over the top of the yellow, or maybe just one of those static electricity logos.

Anyhow, I started scraping the paint off the tank a few weeks back to get through the eight layers of paint that are on there. Should save some weight too. I have already cut the bottom out of the gas tank. It makes a great spot for the charger - I can pull the plug out through the gas cap.

[bennelson]

WEIGHT:

I just checked the front of my Kawasaki Repair Manual. It says the original KZ400 (mine was the 440) weighed 375 lbs.

I weighed the cycle when I had the small batteries in it and it was 400 lbs. I am really supprised that an Etek and 3 18AH SLAs weigh more than the engine, transmission, and mufflers of the original.

The specs on the Optima Yellow Tops say 43 lbs each. I think the original small batteries all together weighed a little more than one yellowtop. I am guessing that the bike currently weighs around 475, which would put it exactly 100 lbs over original stock weight.

The manual also says the fuel tank held 17 liters (including reserve). If gas weighs 6.25 lbs/gallon more or less, then a full tank of gas weighs about 28 lbs.

The weight of the batteries is LOWER than the original gas tank and even with where the engine and transmission were. Center of balance seems pretty good.

[MetroMPG]

Thanks for the DC/DC info. Sounds like you got a better deal than I did. I know if I dig around the web I could probably find the documentation I need. Mine's a VICOR, I believe.

Re: weight. That's a good point - you've got good weight distribution with the batteries where they are now (vs. in the gomi saddle bag location).

Considering that, I think it makes sense to see about getting someone to help you mod the frame to put the 4th batt with the others.

Daox - you're a cool guy for offering!

[bennelson]

Any other questions or comments on this?

[SVOboy]

I still think you should post the advice you pm'd me the other day,

[bennelson]

Here is some general advice I gave out for anyone considering doing a gas to electric motorcycle conversion:

Originally Posted by bennelson
For a motorcycle:

Make sure it has a clean title! You want something that you can register THEN convert. Makes it a lot easier.

In Wisconsin, the "Antique" and "Hobbyist" plates apply to motorcycles more than 20 years old. The Hobbyist plate worked best for what I was trying to do. The cycle I bought was over 20 years old.

Sizewize - you want something big enough to hold batteries, but not so big and heavy that you have to push extra weight around.

Make sure it has two down pipes on it, so you can build a platform to hold batteries on it. smaller motorcycles only have one down pipe, like on a bicycle.

Mine was originally a 440cc engine. The cycle is a medium size and could seat two.

The Japanese make good motorcycles. Apparentyly there was a line of motorcycles known as the "superbike" where pretty much all the parts were practically interchangeable between Honda, Suzuki, Kawasaki, and Yamaha.

Crotch rockets are supposed to make good conversions, because they have a strong, lightweight aluminum frame.

I strongly suggest looking at every motorcycle on the AustinEV site.

Also, "Secrets of EL Ninja" is a pretty good book/plans to have before you do a conversion.

This was my first motorcycle - gas or electric. I bought it with a dead engine and no title for $100 out of a guys garage.

Best thing for you to get is a cycle in very good condition except for a dead engine.

Mine had a really bad wire harness that I had to totally rebuild - I would not do that again!

Hope that gets you started.

Feel free to ask other questions as the need arises.

-Ben

[MetroMPG]

That's an a really good checklist. No doubt it'll be useful to someone looking to do this.

[Stan]

Good stuff, Ben...thanks!

Having had a lot of bikes over the years (I got my first m/c 39 years ago), and restored or modified a number of vehicles, I'd like to stress a couple of points Ben made.

First, GET A TITLE! A title-less vehicle can be a nightmare to register in many States. Wisconsin appears to be fairly accommodating, but in many States it borders on the impossible. If the seller tells you he lost the title, simply ask him to get a replacement from DMV. In every State it is far easier for him to do so than the buyer. If he won't or can't, keep looking for another bike.

Ben laments the sad state of the wiring harness on the bike he bought, and how much work it took to fix it, so here's my advice. Buy a bike that runs! You can check and confirm the condition of every component of a running bike (wiring, brakes, instruments, etc.), but are taking a real crap-shoot with one that doesn't. A running engine (even if thoroughly worn out) has some residual value, but one that does not run at all is near-worthless scrap. Recoup some of the extra cost of a running bike by selling what you don't need on ebay or craigslist. It'll be worth it in the long run.

Thanks again, Ben!