Laptop 12V transformer

[DavidMcMullan]

Would a 12V -> 16V Fijitsu Auto Adapter use power, when connected to the boat battery, but not connected to the laptop? Is it significant enough to require a switch?
Reason for asking is that I have no spare switches on the 12V switch panel and was wondering if I could get away with just wiring it up to the bus without a switch.
Thanks in anticipation.
David.

 

[Landale]

[ QUOTE ]
I could get away with

[/ QUOTE ]

Not a process to be advised! /forums/images/graemlins/frown.gif

 

[Hoolie]

Yes it does! Mine is a Trend and powers the PC LCD screen, uses about 1 amp when the screen is off or on standby. Probably enough to drain your battery during the week!

 

[mikefleetwood]

Yes it will use significant power, even when the laptop is unplugged. In any case, the power feed should be fused and switched for safety.

 

[SvenglishTommy]

Just wire the laptop directly to the 12V supply and save yourself the trouble.

Laptops have inbuilt transformers of their own to deal with the variable voltages they will be supplied with. The different components in laptops all require different voltages. The CPU, memory and various buses require very low voltages that must be within +/- 0.1V. Shoving 12V into the main input should not cause any problems at all.

 

[mikejames]

The current flowing into a laptop fed with 12 volts instead of 16 will be about 16/12 times higher for the same power. The added current may cook things or blow fuses on the circuit board. Any surges caused by load dumps with the engine running (turning OFF other heavy loads) will go through the regulators more easily if directly connected to the "12 volts" of the boat. So it will work but might pop when you turn off the Webasto with the engine running.

 

[fireball]

Never broke on my boat .... but that was with a 15v Tosh fed directly from the domestic 12v battery with the laptop battery removed.
It has been said on here many times that the increased voltage from the mains feed is there to charge the battery as well as run the laptop - so quite often they do not need the whole lot and will quite happily run from the 12v ship supply. My experience has been that the 19v laptops will not run on the 12v supply though - so I have resorted back to kit that we already had.

Never blown a fuse on a laptop - infact, don't recall seeing a fuse inside the laptop! Certainly not on the crapard hell one that is currently in bits in the study...

Still - any supply too the laptop should be fused ... so just feed from a cig lighter or put an inline fuse in the supply ...