Laptop power ?

Gelmaster said:
Most of the inverters i have seen, seem to be pure sinewave now, even the cheaper end of the market.
Can you by any chance recommend a suitable sized inverter size for me?

I am rebuilding my boat from scratch and here is a list of what i am planning to run.......

Port & Star Nav lights
Bow and stern? do i need?
Steaming light
Mast top lighting
4x Small cockpit lights
10 "Led" cabin lights
2x shower lights.......i love my lights!
VHF
GPS
Depth & Speed
Shower/hot water pump
Shower sump pump
Bilge pump
Will i need a horn?
240 offshore to two interior double sockets
Not too sure if i have missed anything here!?
Click to expand...

Most of those are common on boats, some essentil - plus the others Amulat mentions. However as already suggested by others you don't need an inverter, except arguably for a lap top, in which case a 350watt is more than enough. However, as you have probably realised if you want to add 240v kit such as hairdryers you will need substantial battery capacity - and a means of charging. On a 24ft boat you are limited in what you can do electrically by potential battery capacity and charging. I have most of the things you mention on my 37 footer (plus fridge) and have a house bank of 270AH plus a dedicated start battery and charged by a 65 amp alternator - and it is only just enough!. Also have shorepower and a 25A battery charger.

You simply can't fit all that on a 24 footer. So suggest you get a book on boat electrics and design you system to cover the essentials.
 
Tranona said:
Most of those are common on boats, some essentil - plus the others Amulat mentions. However as already suggested by others you don't need an inverter, except arguably for a lap top, in which case a 350watt is more than enough. However, as you have probably realised if you want to add 240v kit such as hairdryers you will need substantial battery capacity - and a means of charging. On a 24ft boat you are limited in what you can do electrically by potential battery capacity and charging. I have most of the things you mention on my 37 footer (plus fridge) and have a house bank of 270AH plus a dedicated start battery and charged by a 65 amp alternator - and it is only just enough!. Also have shorepower and a 25A battery charger.

You simply can't fit all that on a 24 footer. So suggest you get a book on boat electrics and design you system to cover the essentials.
Click to expand...
Surprisingly - I do have all that clobber apart from the shower on a 26 footer, and I forgot to mention the fridge. But I do agree it's overkill, and 24 foot is quite a lot less boat than 26. I do not attempt to do anything at 240 volts except when on shore power, though I do have a small inverter. I have one mains socket for use when plugged in to shore power.
I have two identical general purpose 110 Ah batteries which I use in alternation. My engine is so small that starting it only draws about 35 amps so I don't use a different battery, but keep one fully charged at all times so I can start the engine (it can be started by hand!). I have a 20 amp shore power charger, and can't spare the amps for the fridge unless the engine is on or we are on shore power. I freeze down coolbox packs when on shore power to keep the beer cold when under sail.
 
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Wooppeee, just found my 150w maplins ciggy plug charger. So in the interests of the fun of measuring things...

Mobitronic cheapo 500w invertor, toshiba A660, says on the back 19v, 3.9a. With an ammeter between batts & invertor,

nothing plugged in - 0.26A
Laptop charger plugged in but not connected to laptop - 1.26A
Laptop charging - variable but settled down to going between 6 & 6.5A
Ciggy charger - settled to about 4A

Output from invertor..
IMAGE020.jpg


Mains output..
IMAGE022.jpg


DC was flat at 19.55 both from charger plugged into mains and invertor, 19.33 from ciggy charger.
 
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Conachair said:
Wooppeee, just found my 150w maplins ciggy plug charger. So in the interests of the fun of measuring things...
Click to expand...
Thank you! Some facts. I will now trust my invertor to power a computer. The only measurement I made was the difference in efficiency between inverter and 12->19V Maplin doofer, where I saw a bigger difference than you.

The wave form of the inverter output is "interesting"!

Shame it's over though, there's so much fun to be had from voicing a prejudice completely uncontaminated by fact.

Want another challenge? In a previous setup the NMEA cable from my GPS to my laptop had an unshielded run for part of the way. The engine starting always blew the communication between GPS and computer - mildly but not exceptionally surprising, as lot of amps flying about. (It was simply a matter of resetting the communication after the disruption.) However, STOPPING the engine also duffed over the communication. What's that about? Alternator stopping? Since installing a proper shielded cable all is fine.
 
Amulet said:
Shame it's over though, there's so much fun to be had from voicing a prejudice completely uncontaminated by fact.
Click to expand...

There's a forum called the lounge dedicated to exactly that fun pastime :D:D

I'm just chuffed that someone sneaked onboard and put the maplins jobby back into the locker where i'd already looked more than once :rolleyes:
And I won't bother so much about getting a low power 12v pc, if the laptop can tick over on 1.5A then that's fine. Next thing will to be to play around with the sleep / hibernate. Even with franson gps gate the chart plotter software would sometimes throw a hissy fit and ignore the usb gps input after being woken up from hibernate. V annoying.
 
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