98 S70 voltmeter installation

ignatz · Post by **ignatz** » 05 Jul 2010, 16:41

I get these small flat panel voltmeters from Allied Electronics. They read 4-24 volts dc. Its a Lascar EMV 1200.
I mounted this one in the coin tray, so I can close it if I want. Also, I wired it into the rear cigarette lighter, so it only comes on with the ignition. They draw so little, so you could wire them directly to hot if you wanted. You might want to fuse it if your going directly to hot. There a little over $30.00 now, but I like knowing what going on. I originally put one on my Ducati for peace of mind when I travel out of state, and also have one on my 93 MB 190e and my BMW R1100rs.

AlanS · Post by **AlanS** » 05 Jul 2010, 18:58

I like this idea...seeing that I just had to replace my battery. But, being 'an electricity dummy', I don't know what you mean about wiring 'to hot'. How, exactly should I wire this up. I have an 850, and the underside of the cig lighter is very accessible.

Post by **igel513** » 05 Jul 2010, 19:13

I believe wiring to hot means you connect directly to a live wire.

svendyensen · Post by **svendyensen** » 06 Jul 2010, 14:23

Wiring to "Hot" is usually used when talking about 120V AC (alternating current) wiring (your house outlets), where the Black wire is "Hot", white is neutral, and green/bare wire is the ground.

With a DC (direct current) source (Battery in a car system), the correct terminology would be Positive (+) and Negative (-). The Positive side is Red, and the Negative side is Black.

I think what ignatz is saying, is that if you connect this up to an un-switched/ un-fused source, it would be a good idea to put a fuse on it (and I agree). When you connect this up to the cigarette lighter circuit, it is already fused, and also turns on and off with the car.

To connect the voltmeter up, you just need to connect it to each wire that is on the cigarette lighter, but make sure you have the (+) and (-) correct. Also, keep in mind that in a car, the chassis is always the (-), so you can always use the frame (bare metal) as the (-) terminal.