Reducing 18 volt DC to 12 volt DC

 

I have a cargo trailer that the lights work only when the parking
lights are onin my truck.  This is problematic seeing as we are in and
out of the trailer all day.  I am a contractor that uses 18 volt
Dewalt tools and therefore I own many batteries.  We broke open an 18
volt flashlight and wired 4 12 overhead lights to it and find the
lights to be very bright and in addition they burn out the battery in
less than 20 minutes.?  What to do?  Can I limit the volts?  Will that
extend the battery life?  Lower the light amps?  Phone a friend?
50/50?  Ahhh! I thought I was so clever.  Not so much.  Any help??

 



They will not only be too bright, they will only live too short. Guess you
would also do with 1.5 times overload. You'll have to bring back the voltage
to the 12V required by the bulbs or use 18V bulbs. Guess you will have 18V
bulbs when you have 18V flashlight. Bringing down the voltage is not that
difficult but the easy way spills a lot of power. That's either a series
resistor/bulb or a 12V lineair regulator. Both will produce a lot of heat,
amount depending on the wattage of the bulbs. The best way is a switching
regulator but I doubt a newbie in electronics can handle such a circuit. You
can nevertheless google on it. Lineair has a lot of examples, Micrel is
another. There are much more. If you like experimenting try the "2
transistor Black regulator."

petrus bitbyter

 



Use an auto battery to run the lights and charge it off the 18 V supply.

--
.
.
.
.
.
.
.
.

 

Thought of using 12 volt car battery.  Any better way to charge?  From
my truck?  Cigarette lighter?

 




Cheapest is a resistor from the supply, but ideally you would use a proper
charging circuit. This will prevent overcharging and drying out the battery.

Have you tried a truck supply store? Someone must have done this before.

--
.
.
.
.
.
.
.
.