I live on a boat and get all my electricity from 12 volt battery arrays. The batteries are charged using either 1) alternator on the diesel engine or 2) charger/ inverter powered from shore power at a dock or a portable generator. Yeah, some 120v power while on a dock or running the generator but not usually.
Most everything onboard is powered 12 volt DC, but in reality it's actually fluctuating from 12.4v to 14.6v. So how do electronics like chart plotters, SSB radio, am/fm car radio tolerate these changes? Obviously they do it, and hopefully efficiently.
Is there a simple device to do this?
So far all I could find is " consider a simple PWM driver with mosfets controlled by a microcontroller, and figure out the correct pwm voltage correction empirically and be done with it. " which sounds interesting but doesn't do it for me.
Best Answer
Devices designed for automotive environments have a wide input range that covers the typical automotive 12V rail. They spec the input at 15V on average. Most cars have a nominal voltage of 14.6V while on and charging via the alt.
They work fine at these raw fluctuating voltages. Some like motors or fans do not need regulation. Others, like radios or computers, require cleaner signals so they internally regulate down/up and filter the noisy 12V rail as best they can.
If you need a regulated 12V input, use a low dropout voltage regulator, or a switching regulator.