Volt Meter Install??

[mopowers]

Where's the best place to pull power for a volt meter??

I'm installing one in place of the stock ammeter in my gauge cluster and thought about soldering a wire to the 12v supply in the gauge cluster circuit board. Is this acceptable, or is this too far from the battery?

 

[RedFish]

To tap the wire, drk blue w/ white tracer ( 12 volts to instrument panel ) is how I do it. Measuring the voltage on the copper trace doesn't seem like a good plan.
A inline fuse is optional. This circuit isn't fused other than the fusible link outside. Anyway..
What would burn open first, The winding in the gauge or the copper foil on the circuit board ? To loose a segment of the copper trace will interrupt other items in the panel.
I suppose somebody will find out eventually. Good luck

 

[mopowers]

Well, I've got the cluster apart soldering the pins because they are all loose as well as the slots for the instrument voltage regulator. I figured it would be easy to solder a wire from the 12v trace and connect it to the new volt gauge. I figured it would make it cleaner and easier because the new volt gauge will be installed where the old ammeter was, so it would be self contained without having to connect anything under the dash.

Is the only reason measuring power from the trace is a bad idea because if it breaks, the gauge won't work? I was going to solder it next to the 12v input for the IVR.

I really appreciate your input. I'm just trying to understand why this would be a bad idea.

 

[RedFish]

I perform this gauge conversion for others and provide materials for the install.
They don't need solder tools or skills.
Please yourself.
I don't have further input. It's father time that brings our mistakes to light, mine included. Good luck

 

[nm9stheham]

It all depends on what you want to monitor. The VM is normally used to keep and eye on the battery and charging ciruit health and as near to the battery as you can is the way to go. If you connect it into the dash cluster, it won't have as much meaning for overall system health; there will be voltage drops in the system that will make the readings significantly lower than what you really want to see. You may be dissappointed in what it tells you. Just don't message here and ask why your system voltage is always low! lol

 

[RedFish]

There are 3 possible weak links between drk. blue with white tracer and charging system, ignition switch contacts, bulkhead connector, and fusible link.
This same wire circuit supplies 12 volts to voltage regulator, alt' field, ignition system, etc.. Pretty good indicator of overall health IMO.

 

[nm9stheham]

^^ Right; it is a good monitor point for those weak links. But the voltage becomes low, then is it the batt/alt or one of the weak links? And what 'wiggles' in the VM reading are you willing/wanting to see. Depends on what you want to see. Certainly better than the dash cluster, IMO.

BTW, I have a stock, in-the-dash-cluster-connected VM in one of my rally cars, and it is subject to all sorts of wiggles and drops in the harness and other links. This gets monitored pretty heavily due to the type of racing, but it took a long time to figure out the routine of 'ignore that sudden drop in voltage because device xyz is on'; even the turn blinkers make it jump up and down! It is not connected where it should be to cleanly monitor what I really need, which is charging system health.

 

[mopowers]

Thanks for the input guys. I really appreciate it. So, measuring voltage at the gauge cluster is a bad idea.

So, looks like connecting it directly to the blue switched 12 volt from the ignition switch that feeds the ignition would be the best option?

And to think, I always thought any switched 12v would work... Thanks again

 

[67Dart273]

The thing is, it's only a bad idea from the aspect of voltage drop and lack of fused protection

But so is EVERYTHING ELSE, the regulator, the ignition system, you name it!!!!