Voltmeter

Where's the best place to get an accurate reading to connect a voltmeter? The battery?

Just run a connection straight off the battery terminals?

Depends what you were after...

Know that if there is resistance in the circuit at any given point, it will serve to drop the voltage. So, if you want to know the pure, max voltage of the battery then do test it across the termials.

I ran a dash guage voltmeter to my accesory wire across to ground back when I was dealing with an intermittant regulator on my 77. That way it would not have a load across the battery terminals while parked with the key out. But in doing so, the voltage I read was going through the fuse and ignition and was therefore not 100% accurate.

Are you repairing something? How is the project going otherwise?

If you are talking about a permanetn voltmeter, connecting directly to the battery may drain it dead over time.

Normally the voltmeter would be connected to the switched 12v after the ignition switch. This wold be the brown wire. However, as Qdud points out, there will be a slight difference in voltage at that point compared to the battery. If the wiring and switches are good, the difference may be .1 or .2v, so it's much of a big deal.

However if the bike has bad connections or wires, then the drop may be significant... like anywhere up to 5 or 6 volts, typically. In a stock bike the biggest drop is usually at the fuse holders.

The reason I'd like to run a voltmeter is that I'll planning a trip to Alaska in three weeks and I'll be running heated grips or a heated vest. I know the charging system on these old KZs are marginal at best and I'd like to monitor it real-time if I could.

I just replaced the entire fuse box and will get around to installing a new voltage regulator/rectifier later this week hopefully (it will definitely be installed soon, I have it in my garage. Time isn't on my side). I'll be throwing in a brand new (fully charged) battery the day before I leave for my trip.

Which bike? The 900?

What ignition are you running? If Dyna S, then yes, a permanent voltmeter would be a good idea.

The ground of the voltmeter should go to the battery or a really good ground point, on the gorund wiring, near the battery. The positive of the meter should go to the brown wire coming out of the ignition switch.

loudhvx wrote: Which bike? The 900?

What ignition are you running? If Dyna S, then yes, a permanent voltmeter would be a good idea.

The ground of the voltmeter should go to the battery or a really good ground point, on the gorund wiring, near the battery. The positive of the meter should go to the brown wire coming out of the ignition switch.

Yes, on both accounts: KZ900 with a Dyna S/3 ohm coils.

If I wire it to the brown wire from the ignition switch, the voltmeter will shut off when the ignition is off, correct?

mtbspeedfreak wrote:

loudhvx wrote: Which bike? The 900?

What ignition are you running? If Dyna S, then yes, a permanent voltmeter would be a good idea.

The ground of the voltmeter should go to the battery or a really good ground point, on the gorund wiring, near the battery. The positive of the meter should go to the brown wire coming out of the ignition switch.

Yes, on both accounts: KZ900 with a Dyna S/3 ohm coils.

If I wire it to the brown wire from the ignition switch, the voltmeter will shut off when the ignition is off, correct?

correct.

Be aware, the Dyna S already uses more than double the power that the points ignition used, so there may be less excess power available than before. But I like your voltmeter idea, and as long as it's above 14v, you should have no problem riding indefinitely.

Yep, I didn't crunch electrical numbers with my multimeter like I had hoped this weekend, but I'll be throwing in a new voltage regulator/rectifier soon and will come up with some hard numbers. The heated grips I'm looking at come with 3 or 4 different heat settings, apparently hot is HOT and is rarely used (even by crazy guys riding up in Alaska in the winter with studded tires), so I'll be using the low or medium setting for short periods of time- not all day.

What about using a relay triggered by the brown wire? That may take away the resistance in the factory wiring harness.