On Mon, May 08, 2017 at 07:40:51PM +0100, Phil Thane wrote:
This is Linux related, sort of, so I hope ALUG don't mind the apparently random question. (cc'd to my old LUG in Wrexham, they're used to mad questions from me).
I have just bought a canal/river boat and want to use my Linux laptop on it. The PSU for it is labelled 19v, 4.7 amps. The boat runs on 12v. The simplest but quite pricy option is to get an inverter to create 220v AC then use the standard PSU but apart from cost it lacks elegance.
Welcome to the boating fraternity! We have a little canal boat in France and I have the same issue. There is a *very* simple solution, you can buy 'step up' power supplies which take 12 volts input and can output (adjustable) 15 to 30 volts. I use one of these on our boat.
The boat has 2 completely separate circuits (at present, I'll probably re-wire it next winter). There is a 12v battery charged by the engine that is used for the engine starter and a few ancillaries such as the horn and nav lights. The there is another 12v battery charged by a solar panel on the roof used for cabin lights.
If I connect the two in series I should get 24v then I should be able to acquire (or even assemble) a DC-DC voltage regulator to bring it down to 19v.
Yes, you want to keep the 'leisure' circuits separate from the engine starter. If you flatten the leisure battery you can still start the engine.
Get a step up supply as I suggest above!
Something like this:-
http://www.ebay.co.uk/itm/LTC3780-Automatic-Step-Up-Down-Regulator-Power-Sup...
However there are many more and you can find what you need cheaper, this was just the first I found easily.
Here's another, very like the one I am using:-
http://www.ebay.co.uk/itm/100W-DC-DC-Converter-Boost-3-5V-Step-up-to-30V-LED...