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.