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After reading several discussions regarding battery charging problems and related issues, I thought I’d look into adding a voltmeter to my ’09 coupe. I found the kind you can plug into your cigarette lighter with a digital LED display (and sometimes a USB charging port), but also found small rectangular digital panel meters that just happen to fit exactly into the car’s removable ash tray. Because the tray is right next to the 12 volt socket for the lighter, I used a DIY male accessory plug to power the meter. This is, admittedly, not an essential upgrade modification, in that unless you suspect your alternator, voltage regulator system, and / or battery is becoming defective, monitoring the electrical system’s voltage on an ongoing basis won’t tell you much. But the meter / plug are instantly removable and the installation is very easy, requiring no modification of the ash tray. It’s almost “plug and play,” literally. You could also use it temporarily in other vehicles, golf carts, etc. The installation looks neat and clean, except you can see a small portion of the wires connecting the meter to the plug. If you can find a fused accessory plug short enough (i.e., no longer than the OEM cigarette lighter), you can even close the ash tray / lighter door with the meter inside.
If you’re interested in making this, use a Drok brand mini LED digital meter. There are similar meters available from different manufacturers, but they have slightly different physical dimensions, and may not fit exactly in the receptacle. I used a small piece of black electrical tape on the top and bottom of the meter to make it fit snugly. I tried blue digits at first but they were too bright at night. Red works fine, both day and night. The meters also come w/ green or yellow digits. The Droks are available from several sellers on eBay for about $11 and I got mine from a U.S. shipper (fanteller) to decrease shipping time. Also on-line there are a variety of male accessory plugs available, but the typical ones are fairly long. I found a very short one with a right-angle connector for the wires at a local electronics supply store (Philmore#48-785, LKG Industries, Rockford, IL, $3 in the store). I haven’t searched for it on-line; the shortest one is needed only if you want to be able to close the ash tray door). Usually the plugs have small screws inside for connecting wires, but the Philmore does not. You will need to solder the wires directly to the connectors. Conveniently, the wires from the meter easily reach the plug connectors. Remember to observe polarity: red wire to the end connector, black to the side connectors.
Last edited by runzgood; 12-06-2015 at 10:12 PM.
Reason: missing word
they make voltmeters that plug directly into the 12V socket. some even have USB outlets to charge your phone, etc.
the trick would be to find one low profile enough that allows the door to close.
Right. There are some very compact and short USB port plugs. If I can find one I can get into without destroying it, the meter could be connected to the 12 volt input and then that could be used instead of the accessory plug. That would be neat, more functional, and the door could be closed also.
12-06-2015, 02:32 PM
