Modern Vespa

So I just bought one of these:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98479

Mainly cause I am adding auxiliary lights and stebels and cigarette lighters and blah blah blah and I would like to have the voltage info infront of my face at all times, but mainly cause it looks RAD.

Anyhow...

I thought this was going to be a no brainer - just run a wire to the battery and see what is going on - but after some research online, it appears to be more than just a couple wires and drilling a hole.

1. Apparently, running it from a battery source will lead to a drain.

2. Also, it was suggested that the power is drawn from the ignition switch or a fuse box.

3. And finally, need to run a 5A fuse.

These are my questions:

Is #1 true? If not, then I will just run it to the battery. If it is then...

Where do I get the power from? Ignition switch and fuse box is Chinese talk to me. Maybe someone can gimme me more specifics to my application on my ET4.

Then, if I am drawing power from a fuse box, why do I need to do #3?

Thanks for any and all help in advance.

1. Yes, because even the most efficient voltmeters take a little juice to operate.
2. If you take it from the "downstream" side of the ignition switch (or a fuse box connection that is switched by the ignition), it eliminates the problem with No. 1.
3. If you are certain that any accessory (including but not limited to the voltmeter) is in fact connected through a fuse or circuit breaker, then theoretically another fuse isn't necessary. But if you're not certain, fusing it won't hurt--and it might prevent a problem with a short circuit down the road.

And finally, if you don't know what you're doing, you really can cause some serious problems, like frying your alternator, etc. There's a neat book out there for boaters, called the 12V Boater's Bible, which although oriented toward boats, has some pretty good basic wiring explanations that might help fill the gaps in your knowledge. Any boating catalog has it, or you can order it through Barnes & Noble or other bookstores.

Cary

wire it to your ignition switch and you should be set , I will look at my ET4 Shop book to see what wires

I am fairly confident that I could get this, and other RAD mods, done on my bike. I was slightly intimidated with the wiring of the stebel nautilus (my first mod), but since I crushed that bitch without a hitch I think I can get most of my stuff done no prob.

Also, I have been doing a ton of reading on this forum as well as others absorbing as much info as possible, as well as asking as many questions as I can (like this one) only to get more info.

AND, my uncle is a biker/mechanic. He lives in Rhode Island, so I can only get him on the phone which I do when I have a basic understanding of what I need to do after my research and questions are answered.

Here is a pic of the ET ignition I pulled off the forum.

How does one determine the "downstream"?

And do I just tap into wire and fuse it with the suggested 5A fuse?

Anything else I should consider?

Thank you much!

Thank you sire! (or Madam)

A multimeter is your friend. If you don't have one, even cheapies can work well for scooter work.

Set your meter to an appropriate DC voltage setting--usually 30.

Attach the black lead to any ground, then move the red lead to the different connectors on your switch to see which one is cold (0V) when off and hot (12V) when the switch is on.

Now you know where to tap into the switch. I think adding the extra fuse is a good idea if you connect here. Better to lose your new gauge function than to walk. I once owned a BSA and know about walking (and pushing).

P.

No advise to give sorry, but....
Where / How are you going to install?
I would love one of those and a tach on mine..
Space and weather proof are two issues to factor in..

I have one on the way from harbor freight. I suppose that will all make more sense when I get it and call good old uncle John the mechanic. I am going to document my mods from here on out since it seems to be a big hit around here.

Hopefully FireJ will get back to me before my multimeter comes in the mail so I can get to this chop chop.

Thanks everyone!!

"Downstream" is the cold side of the switch when it's off. "Upstream" is where the juice is coming from. Your new multi-meter will tell you which is which.

Cary

so whatever wire is getting power when the bike is totally off (keys out) is the one i need to tap into?

It has been 5 hrs...
Are you done yet?
Waiting......

No, no, no. You want to tap into the wire that is getting nothing with the key in the "off" position, and 12V with the key in the "on" position.

You want your voltmeter out of the circuit when the bike isn't on. If it is still connected, the current to run the meter will be a full-time drain on your battery.

You only need the meter to indicate voltage when the bike is running.

P.

Since I am still waiting for all the components and to gather as much info needed to complete all of my mods, I probably won't have it done til the weeks end.

HMMMMMMMMMMMM...

I dont think that meter is waterproof-its made to use inside a car. Check on customdynamics.com or some motorcycle websites ----there is a small waterproof indicator with leds that shows voltage and can be mounted anywhere for about $35.00 that would probably work better. Art