On my boat I have a number of electronics devices that run on 12V DC and normally get their power from an AC transformer. They include a media player, a network router, and a portable hard drive. Since the boat is wired for 12V DC I would like to set these up to run directly off of the boat's DC. This will free up a lot of power strip space, and eliminate the inefficiency and need to run them through the boat's DC to AC inverter when not connected to shore power.
I've read that this is dangerous territory since the boat's DC system is subject to surges and noise, for example when the starter or the electric windlass are engaged or the VHF radio is in use, and that this can damage electronics directly tied to the boat's DC system. I've also read that while the marine 12V system's voltage can vary from 12 to 14.4v (depending on whether the alternator and charger are engaged), these devices are not tolerant of these voltage fluctuations and are designed to expect a constant regulated voltage from their AC-DC transformer (wall wart). There are marine surge and noise suppression products available ranging from $50 - $200 to address this concern.
The marine market is renowned for its high markup. For safety and navigation applications where help is far away this is merited, but honestly if any of this equipment I am connecting failed nobody would get hurt or lost. The price of the commercial products seems high and I suspect the circuit should be relatively simple. The loads are all less than 5 amps.
I am interested in implementing a custom circuit to accomplish this protection.
Where should I start?
Are there reference designs for such a thing? What are the critical components: voltage regulation, surge suppression, noise suppression?
I've done a bunch or Arduino projects and am comfortable soldering, breadboarding, and putting together a custom through-hole project, but I lack a formal EE education and background. I've also done quite a bit of re-wiring on the boat so am pretty comfortable with the marine DC distribution and circuit protection and the ABYC standards.
A couple examples of commercially available products:
edit: is something like this a good starting point: http://www.ti.com/product/lm5118 and if so what else should I add? Ferrite chokes?