"Low voltage"

[maestromaestro]

My Escort Redline detector - hardwired using a fuse tap - shows varying voltage (bouncing between 10.4 and 11.2V), and every so often (which is to say often enough) shuts down due to "low voltage" - essentially assuming that the engine is off. However, the actual battery voltage is fine, between 12.5 and 13V. So, is this an issue with the ground connection for the hardwiring or what?

 

[Intuit]

Hopefully the wiring is damaged. Please note the following...
https://www.r6-forum.com/forums/5734342-post26.html
https://www.r6-forum.com/forums/5734344-post27.html

This is a perfect case for voltage drop testing. It helps you isolate bad connections. It is necessary to saturate the connection you're testing. You won't disconnect anything in the circuit to run this test. Use a straight pin or paper clip to pierce wiring insulation (to get a reading) where necessary.

IIRC (unsure) higher than 5 or 6% voltage drop is indicative of a problem. (so ~0.65v out of 12.6v for example)

To test the device's connection to negative/ground, connect one volt meter probe to the wire at the back of the device. Connect the other volt meter probe to the negative battery terminal. Your reading is voltage drop.

You can repeat the test for the positive side.

You can set your probes, directly before/after the volt tap device to get a voltage drop for specifically that.

 

[maestromaestro]

Thanks. I will chase it. I have a Fluke with a bunch of attachments, including the ones to pierce insulation. So - I shouldn't just test ground to ground, you actually suggest that I run a wire directly to the negative terminal of the battery to measure (if there is any) voltage drop?

 

[Intuit]

I agree with going with whatever is quickest, and planning the next test (if necessary) from there. In this case it doesn't really matter where you start. Needless to say, if there's no drop between battery and device, there's no reason to run any further tests on that side of the circuit.