Hey guys I am in the process of installing an Auto dimming mirror and I am trying to find a 12v power source for it. I was down in the fuse box last night with a multimeter and everything kept reading 13v. I don't really want to blow my mirror by plugging it into a 13v source but that seems to be all that I can find. Any ideas?

 

Thats what your battery is putting out at a full charge. Which is fine and around what it should be. 13 volts wont damage your mirrior. Good luck.

 

Your charing system will show 13.8 to 14.5 volts, while the motor is running, depending on the state of charge the battery is in at the time. (If you have an Escort 8500, you can set the display to monitor battery voltage). A fully charged battery sitting for an hour or so should read 12.5 volts.

Don't worry about your mirror. I can take much more than 13 volts and not burn up.

 

Yup, most DC devices are designed to tolerate some fluctuations in voltage so as long as you're within a few volts +/-2V, you should be fine.

 

Possibly not on the low side in some cases. Many devices for example work on 5.2 volts using a voltage regulator. Many of these require 2 volts above the operating voltage but will tolerate upwards of 28 volts. The same regulator with one leg floated can be used for nearly any voltage up to the max but still need at least 2 volts above to be stable. For cars I have typically designed them at around 9 volts when I was experimenting.

On my other car it seems that 11 volts is minimum before it fails to operate so I watch this carefully when operating my aftermarket audio system. This causes some interesting problems for those that use one of those battery chargers with a jump starter function. As soon as a start is attempted the jump starter will often drop out if it sees the voltage above a certain level but the starter will drop the voltage down far enough to not allow the car to start. Sometimes one wishes for the old days when things were simple.

 

Well I was successful in getting my mirror to work. I plugged myself right into the fuse box and everything is working perfectly.

Thanks for the info.