newbie electrical question

[ron halverson]

Hope someone can help i have a 1973 starcraft stairmaster 8 in great shape it has a 12v converter to run the lights with a switch to switch between a battey and 110 power i know this is pretty much standard on pop ups what i was wanting to do was add a 12v recepticle to plug in a small fan or such i just tapped into the wires coming off the converter going to the over head lights but i checked the voltage and it reads 16.32 why is this wont this blow any 12v device that i may hook up ?? please help is there any way to do this

[Nemesis56]

Hope someone can help i have a 1973 starcraft stairmaster 8 in great shape it has a 12v converter to run the lights with a switch to switch between a battey and 110 power i know this is pretty much standard on pop ups what i was wanting to do was add a 12v recepticle to plug in a small fan or such i just tapped into the wires coming off the converter going to the over head lights but i checked the voltage and it reads 16.32 why is this wont this blow any 12v device that i may hook up ?? please help is there any way to do this

Are you getting 16.32 volts output reading from the converter or are you reading a label on the light?  If from the converter, unplug it from the 110 AC power and do a reading.  12 volts is a nominal reading/range.  It may be higher or lower.  If it's a 16 volt fan on a 12 volt converter output, it will run a little slower by about 25%.  If it's 16 volts converter output on a 12 volt fan, the fan will run faster by about 25%, but have a  shorter life.  As a general rule, amperage is what blows fuses and trips circut breakers.  Voltage is the potential.  Amps are the actual current flow.

[ron halverson]

it is the actual reading from the converter i dont have a battery installed on my camper although the converter diagram shows it being able to have a battery and switch between the two

[wavery]

Are you reading the voltage at the converter with "0" load? If so, you may get a high reading. Try putting a load on it, like a light or something. I think that it may come down to about 12.8v.

[AustinBoston]

Are you reading the voltage at the converter with "0" load? If so, you may get a high reading. Try putting a load on it, like a light or something. I think that it may come down to about 12.8v.

That was my first though as well; many cheap power supplies have no overvoltage protection, so no-load they may go much higher than their rated voltage.

If the voltage does not go down significantly when you turn a light on, the converter may be suspect...it may still be OK to operate, but everything you plug into it will have a shortened life.  I would avoid plugging expensive devices into it such as a 12V television or laptop computer.

Austin

[wavery]

I suspect that the more that he plugs in, the lower the voltage will drop. He will probably blow a fuse before the voltage reaches 12V.

The converter may be looking for resistance and isn't finding any. Once it finds resistance, it may settle right out between 12 & 13V. 14V is pretty harmless but as you say, over 16 will shorten the life of most things.