Installing volt meter

I'm installing a small digital voltmeter on my KZ900. Can anyone suggest a good place to tap in to switched 12 volts that would be easy to tie in to? All the lights I've checked so far are like 9.5 V, Haven't check in the headlight bucket yet. Should the key read batt voltage? How hard would it be to tie in there?

I always worry about these old bikes charging systems breaking down at night sometime when I'm 50 miles away. Had it happen on my old CB650, which are notorious for eating stators cuz the exhaust was routed too close to the alternator and they run hot all the time. Luckily it didn't happen at night and I wasn't too far from home, but was riding along on the battery and had no clue the alternator went until the bike started running like hell.

Yep, they come in handy. I installed mine about a month ago. I pulled 12v+ off of my coil due to my m-unit behaving badly.
I pulled my ground from inside the headlight bucket.

I'm having trouble finding a schematic for your bike. Maybe someone else can chime in.
On several years there appears to be a brown wire that comes into the headlight bucket. This wire is 12v+ for the neutral and oil pressure light.

You should also be able to pull your ground from inside the headlight bucket as well. It's possibly a black wire yellow stripe.
Verify with other members and a volt meter.

Get a three-wire voltmeter, not two-wire. The two-wire uses same voltage to read as power, and is not accurate. The three-wire uses independent wires for reading and power.

This is how I did it, but I have a newer Zephyr 750, and it came with available accessory leads out of the fuse box with plug in connectors.. White/blue power and Black/yellow ground. Accessory power is connected to Battery/RR (+) power through a fuse, and does not go through the ignition switch. ..meaning is always on.

......so I connected the voltmeter power to the horn power wire (brown), tapping with a expensive posi-lock T. That means voltmeter is only powered when ignition is one. An then extended voltmeter read wires to the accessory leads, and that is power am reading. I know you may not have accessory leads, but gives you an idea. Basically, tap on any brown wire (ignition power) to power the voltmeter, and then read a close you can to battery leads or RR delivery, through a fuse, in case voltmeter gets a short.

If you want the most accurate reading of battery voltage and the charging voltage to the battery, the best place to get these readings is at the battery. Run 2 wires. A fused wire to the plus battery terminal, and the other to the negative terminal. Most volt meters are very high resistance and will not cause your battery to go dead if the bike is unused for a few weeks. Add a switch if stored longer.
If tying in to existing wiring, you will always be using a fudge factor, and mentally adding a volt or two to the displayed reading.

I ran a 2 wire.
Granted, it's a more accurate 2 wire.
www.adafruit.com/product/460

My voltmeter display is .1v off from a reading directly on battery terminals with a Fluke 376FC.

F64 wrote: I ran a 2 wire.
Granted, it's a more accurate 2 wire.
www.adafruit.com/product/460

My voltmeter display is .1v off from a reading directly on battery terminals with a Fluke 376FC.

Did you include a switch?
I can see the advantage of a 3 wire meter. The sensing wires can be run directly to the battery and the power wire paralleled off any wire controlled by the ignition switch. This would also eliminate the concern of battery drain on seldom ridden bikes.

No eBay APP ID and/or Cert ID defined in Kunena configurationI have one like this on my boat. It includes USB receptacles.

ckahleer wrote:

F64 wrote: I ran a 2 wire.
Granted, it's a more accurate 2 wire.
www.adafruit.com/product/460

My voltmeter display is .1v off from a reading directly on battery terminals with a Fluke 376FC.

Did you include a switch?
I can see the advantage of a 3 wire meter. The sensing wires can be run directly to the battery and the power wire paralleled off any wire controlled by the ignition switch. This would also eliminate the concern of battery drain on seldom ridden bikes.

No switch needed. I'm pulling off my coil wire which comes directly out of my m-unit.

hugo wrote: ... The two-wire uses same voltage to read as power, and is not accurate. The three-wire uses independent wires for reading and power.

That doesn't make any sense. Two or three wire doesn't have anything to do with how accurate it is.

cb900f wrote:

hugo wrote: ... The two-wire uses same voltage to read as power, and is not accurate. The three-wire uses independent wires for reading and power.

That doesn't make any sense. Two or three wire doesn't have anything to do with how accurate it is.

It's because the sensing wire and the power wire are separate. In this case it probably doesn't matter too much. But the fact that the regulator/rectifier on some of our bikes uses a sensing wire and doesn't just check it from the positive supply shows why having a separate sensing wire is important in a more complicated circuit.

If you are checking with a 2 wire then you are seeing voltage drop across whatever circuit you are tapped in to and not necessarily the actual voltage of the battery.

I'd considered installing a microswitch somewhere but would prefer to not have to bother with having to turn it on and off. Running it directly off the battery is balls on with my volt meter but everywhere else I look it's all over the place. I'll check the horn and the brown and black and yellow wire in the headlight. If not I'll put a tiny switch somewhere. If it's a little off it doesn't matter to me too much. I put one on my CB650 and tied it into one of the fuses between the fuse box between the risers. it always indicated about a volt off so I got used to seeing it at that voltage. If the charging system went out at least I'd see it right away. Thanks for the suggestions you all.

Thst's weird.
It sounds like you have some crazy voltage drops.