For several years, now, I've been trying to find a cigarette lighter plug-in voltage meter like Chris (F350-6) has referred to in some of his posts, but have not been able to locate one until just recently. I purchased a couple of units off eBay (link below), but am having some electrical/electronics issues, and I don't know/understand enough bout electronics to know how to resolve the problem. I do have one idea, but am not certain that it will resolve all the issues I'm seeing, hence my request for input from those who are much more k nowledgeable about electronics.

Green LED Display Cigarette Lighter Battery Electric Voltage Meter with USB Port | eBay

Problem 1.
When I leave the voltage meter plugged in after shutting down the engine, my key fob will not work, and this is true on both my Excursion and my F250, so it is not a vehicle specific issue.

Problem 2.
When I have the voltage meter installed and am running down the road with the radio on, I get sporadic episodes of mild-to-strong interference with the radio reception.

My idea for Problem 1.
Install an additional 12v plug which is not always on (relay switched to the ignition (or just a separate power switch) so that it is only on when the truck is running (or when I manually switch on the power supply to the plug). The thing I'm not certain about is whether or not this will resolve Problem 2 (radio interference).


What do you guys think (or KNOW) that I should/could do to fix both of these problems?

Is some electronic shielding required for one or both issues (if so, how best done)?

Thanks ahead of time for any and all input.

 

Dump the meter Pete! If you didnt have those issues before the meter, fix it at the source. Thats a poorly designed meter.

This one works very well with no interference:

 

I can't say which one to get as I don't have one (in the market) but my first thought is also to dump that unit and start over.

 

I had already seen that one, Jeff, and chose to try the route I took because of its small size and the presence of a USB port. For now, I just pop it in shortly after starting up and then pull it on the first sign of interference. It still gives me the troubleshooting capability I wanted, but is just more of a pain to keep inserting and removing every time I drive. I might just let it ride in the center console and only use it when I have a concern or doubt about vehicle voltage.

 

Have you tried it in the auxiliary power port rather than the cig lighter? the key fob not working is really a head scratcher, those things must really be throwing off a whole lot of RF.

I vote you give them to a co worker you don't like and start over

 

Actually, Steve, the only place I've tried it is in the aux port because I keep my low profile USB phone adapter in the cig lighter port.

The RF issue is why I was wondering if there might be some way I could shield the unit (and/or wiring). I was thinking that I might try to cover the whole thing with some heavy duty aluminum duct sealing tape on one of them to see if that might "clean up" the RF issue (obviously avoiding the power connectors with the metal tape).

 

There are lots of ways to clean up RFI, including shielding and ferrites, but I have to agree with the rest and say dump it. A plug-in voltmeter generating so much noise that your keyfob and radio don't work just drives me crazy! *end rant*

 

Although I understand what you guys are saying, I'm going to just keep them on hand (i.e. in the console) as a potential troubleshooting tool until I find an acceptable replacement. I might just go with a panel mounted rectangular version which I will hard wire into the electrical system.

 

Thats what I want to do!

 

This one was recommended by, IIRC, some sportsmobilers. 4.5 Stars and 102 customer recommendations. $8.07