Designing an electrical system for a 30ft boat.

[Anders_P42]

Why the hate towards droppers? Fit something decent and you'll rarely have a problem. The below droppers come with lifetime warranty such is their confidence in build quality. And they're not expensive, if you're concerned of failure keep a spare onboard.

http://alfatronix.com/assets/Uploads/2857-powerverter.pdf

Anders

 

[jfm]

Wow, that's possibly the most sophisticated dual voltage DC setup I've ever heard of!
Just one thought: assuming that you have AC available at all times, either through dock, genset or inverter, wouldn't it have been easier to connect the 12V charger to the inverter (as I guess is the main fridge, for instance ) and get rid of (3) altogether?

Yep you could do that. This is one of those topics where there are x10 ways to do it, and you can debate at length which is best, and you end up with "much of a muchness" as your answer. Fairline offered the above included within base price so I accepted it! I like backup and it gives me more ways to get 12v than I can count (ditto multiple ways to get 24v too)

FWIW but a bit OT, ref fridges, my fridges are inverter powered but via the main switching relay so they are not fed thru the inverter when there is 230v available from genset or shore. I agree you can do it permantley thru the inverter if you prefer that and I'm not saying there is a right or wrong here. Indeed I have one SubZero 110v 60Hz fridge (the unit I wanted was only available from Subzero's USA range not their Eur range) and that is permanently powered from a US spec 24v inverter

 

[burgundyben]

The boat came with a brand new echosounder, plotter and DSC radio which are all 12v only.

I have a plan, the entire boat engines, dash, batteries, charging, fridge, heating, nav lights and water pump will be 24v, the only panel will be 24v. A single switch for instruments to power the sounder/plotter and radio will run straight into a 24 to 12 dropper.

Despite not liking droppers and converters it'll be simplist. It will achieve my goal of turning cabin lights off at night and everything being open circuit.

 

[vas]

and everything being open circuit.

is that an obsession of yours, or is there any other reason behind it which I'm missing?

We are talking a few mA for the night for the dropper, probably less than what the radio consumes on standby for an hour, cannot be that important, can it?

cheers

V.

 

[burgundyben]

is that an obsession of yours, or is there any other reason behind it which I'm missing?

We are talking a few mA for the night for the dropper, probably less than what the radio consumes on standby for an hour, cannot be that important, can it?

cheers

V.

I don't like to think that there is electrical inefficiency, secondly, firse risk, much safer at night is everything is open circuit, no?

 

[jfm]

I don't like to think that there is electrical inefficiency, secondly, firse risk, much safer at night is everything is open circuit, no?

In reality that never happens. Even on a quiet night you could have turned on your anchor light, deck lights, GPS drag alarm, anchor winch system ready to go, fridges, icemakers, tell tale LEDs marking other switches, WC control panels, generator auto starter system!:encouragement:

 

[burgundyben]

In reality that never happens. Even on a quiet night you could have turned on your anchor light, deck lights, GPS drag alarm, anchor winch system ready to go, fridges, icemakers, tell tale LEDs marking other switches, WC control panels, generator auto starter system!:encouragement:

I really really really want everything open circuit at night.

No leds. They don't look right on a Fairey.