What's new

Electrical impedance and gauge readings

JNHEscher

Red Skull Member
Joined
Jun 7, 2020
Member Number
1892
Messages
2,899
Loc
Dogwood, MO.
In due time, I'll be needing to install new gauges in a project (the MCI bus to RV) that will be reading through roughly 40' of wire. As many know, the longer the wire run, the greater the total impedance. This causes gauges to read incorrectly because of the voltage drop. Even if I up the wire gauge, I'm sure I'll still have some voltage drop to deal with.

The two thoughts that come to mind to correct the voltage are either matching a parallel resistor to decrease the impedance of the wire, or increase the voltage that is sent to the gauge or sensor. Depending on what gauges I choose, I may or may not be able to pull the needles off to adjust their position. I don't think a parallel resistor would provide the same, relatively linear voltage that the gauge would need and I'm not sure if I could push another 2-3 volts through without causing damage.

Having not done this before for a situation like this, I'm wondering if anyone has heard of doing so. If I can grab a pair of cheap gauges to mess with, I'll do some testing. Just wanted to read some IBB member thoughts on it first. I guess think of it as a step-up transformer station on a micro scale.
 
The guages should be regulated internally and read the same if they have 12v or 14v feeding them
get 40ft of wire and measure the resistance,its not going to be much,a few ohms with a 0-90ohm guage will not make much of a difference in the reading
Obviously the voltage guage will be off but most of them you wont know the difference between 14.3 and 14.5 unless they are digital
 
Last edited:
Top Back Refresh