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.
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.
Anyone see any problems with that?
-- Phil Thane
www.pthane.co.uk phil@pthane.co.uk 01767 449759 07582 750607 Twitter @pthane
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...
On 8 May 2017 at 19:40, Phil Thane phil@pthane.co.uk wrote:
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.
Actually, a simpler option is replacing the laptop... If you have an expensive laptop that's not a good choice, but it could otherwise well work out cheaper to replace the laptop, maybe with something smaller that charges from 5v (as so many things do these days). If it's an expensive new laptop the warranty may be void if the power isn't supplied by the manufacturer's PSU, for example, and this laptop might require 19v but your next one (or your guest's one) might need something different...
Otherwise as others have said stepping the voltage up is easy enough. You'll probably want an inverter anyway at some point, so if the laptop is just for occasional use that might still be the best option. Inverters are relatively wasteful but universally useful.
Personally I'd want to standardise as far as possible on 12v DC (direct from battery), 5v DC (USB devices like phones) and mains. On the other hand if it was a decent laptop, critical to my work, and I planned on staying on the boat using it for months at a time, then I'd be wanting the most efficient option I could find even if it only worked for that one device.
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.
I think we're fairly universally against that option though :-)
As a fellow (but very novice) boat owner, welcome to the water!
On Tue, May 09, 2017 at 09:12:47AM +0100, Mark Rogers wrote:
On 8 May 2017 at 19:40, Phil Thane phil@pthane.co.uk wrote:
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.
Actually, a simpler option is replacing the laptop... If you have an expensive laptop that's not a good choice, but it could otherwise well work out cheaper to replace the laptop, maybe with something smaller that charges from 5v (as so many things do these days). If it's an expensive new laptop the warranty may be void if the power isn't supplied by the manufacturer's PSU, for example, and this laptop might require 19v but your next one (or your guest's one) might need something different...
The power supply I suggested is adjustable. I use it with both my Lenovo (20 volts if I remember) and some Acer laptops (19 volts).
Otherwise as others have said stepping the voltage up is easy enough. You'll probably want an inverter anyway at some point, so if the laptop is just for occasional use that might still be the best option. Inverters are relatively wasteful but universally useful.
They're not *that* inefficient, probably around 80% usually, but they won't be so good on a small load like a laptop. The other problem you may get is that 'modified sine wave' inverters (the cheaper ones) don't always play nicely with switching power supplies which are almost universal with laptops (and many wall warts) nowadays. I had a tiny (as in for a DECT phone) wall wart switching power supply *kill* a 3kw inverter.
Personally I'd want to standardise as far as possible on 12v DC (direct from battery), 5v DC (USB devices like phones) and mains. On the other hand if it was a decent laptop, critical to my work, and I planned on staying on the boat using it for months at a time, then I'd be wanting the most efficient option I could find even if it only worked for that one device.
That's basically what I have on our boat but with the addition of some step-up DC<-->DC supplies for laptop (as described here) and step-down 12v to 9v ones for running a router as there is a Beaglebone Black on the boat running all the time and it connects to the internet through the router.
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.
I think we're fairly universally against that option though :-)
Yes, unless you are fully 24 volts (which many larger boats are) I think it's a bad idea.
** Phil Thane phil@pthane.co.uk [2017-05-08 19:41]:
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.
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.
Anyone see any problems with that?
** end quote [Phil Thane]
Based on my experience of boats on the Broads (closer to what you have probably) and my own sailing cruiser (less use of power and just has a single 12V battery at present) what about looking into chargers as used in cars. I have one for my Lenovo that plugs into the accessories socket in my car and directly into my laptop. I think it is probably just a few components (resistors, etc.) to adjust the voltage inside the plug. It doesn't charge quickly, but does keep things going on the road - or afloat when I wire up a suitable connector; I don't use the laptop often on the water so a fully charged battery does the trick, and in marinas (which I haven't used for years) you now have mains hookup much like camp sites these days.
Oh, hi again, btw. I tend to collect LUG lists, particularly in places I like to visit, hence the ones that cover Wales and Norfolk :) Oh, and Suffolk of course! ;)
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Chris Green -
Mark Rogers -
Paul Tansom -
Phil Thane