I installed a 12v to 19v converter & wired up the plug to fit the laptop but I get the message "The Smart AC Adapter power output is too low for this computer".

I did the same thing on my last boat, it was an older lappy though, and it worked fine.

I then bought, off ebay, a cig lighter adapter specifically for my HP lappy & I still get the same message.

There is a centre pin in the plug, apart from the +ve & -ve, that senses the power requirements of the laptop & this won't let it charge.

Does anyone know how to make this work so I can run my 19V lappy from my 12V system??????

Try using a 12 volt sine wave inverter you can pick them up on e-bay small ones plug directly into cig lighter socket and will charge your laptop.

It's going to suck the power out of your battery no matter how you try to get around it, I cannot see how you can charge up a 19 volt battery with a 12 volt battery, as the 12 volt battery only has the 12 volts, you may have to get a second 12 volt battery, but then electricity is a funny thing so it's possible (even likely) that I'm wrong.

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Bruski068 said..
It's going to suck the power out of your battery no matter how you try to get around it, I cannot see how you can charge up a 19 volt battery with a 12 volt battery, as the 12 volt battery only has the 12 volts, you may have to get a second 12 volt battery

Lazza has a bit of spare battery power on his boat Id say Bruski all depends on your own boats and spare amp hours you have on your boat.
I think Lazza just wanted to get his Lappy going .
But I know what you mean though

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Lazzarae said..
I installed a 12v to 19v converter & wired up the plug to fit the laptop but I get the message "The Smart AC Adapter power output is too low for this computer".

I did the same thing on my last boat, it was an older lappy though, and it worked fine.

I then bought, off ebay, a cig lighter adapter specifically for my HP lappy & I still get the same message.

There is a centre pin in the plug, apart from the +ve & -ve, that senses the power requirements of the laptop & this won't let it charge.

Does anyone know how to make this work so I can run my 19V lappy from my 12V system??????

what wattage is your official power supply?

apparently you can make a standard 2 conductor power supply work by tying the 19V to the 'Smart Pin' with the appropriate resistors to give the correct voltage (which tells the laptop how much power is available from the supply). as you have found, if the 'Smart Pin' isn't sensing anything (or the wrong voltage) then the laptop won't be happy. have a look here (with the usual disclaimer about not messing with electrical stuff if you don't know what you are doing):

www.techspot.com/community/topics/smart-pin-voltage-to-capacity-correlation-for-laptop-power-supplies.178875/

This is the best part of seabreeze swapping ideas and knowledge

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fishmonkey said..

apparently you can make a standard 2 conductor power supply work by tying the 19V to the 'Smart Pin' with the appropriate resistors to give the correct voltage (which tells the laptop how much power is available from the supply).

www.techspot.com/community/topics/smart-pin-voltage-to-capacity-correlation-for-laptop-power-supplies.178875/

Thanks for that ^^^ - this is exactly what I need

I think the wattage of the "official" power supply is 90W (I'll check when I get on the boat) & the 12v > 19V adapter is 152W 8A.

I'm definitely no "techy type" but I'll have a look in Jaycar & do some more researching & give it a go. I'll try putting a resistor (200k?) between +19V & the Smart pin to get the required Voltage. I'll measure what it is on the "official" power supply (13.5v?)

I don't really care if the laptop charges I just want it to run off the house batteries.



You're right HG - the best part of seabreeze is swapping ideas and knowledge.

My older laptop was a Toshiba techtra which had the battery removed and ran straight of the ships battery.

My current machine is a newer Toshiba with the battery removed an there is a step up convertor. Removing the battery reduces the current draw. I think mines about 2 amps. One of these days I will convert to a 12v computer and a large LED LCD screen TV.
I have a Logitec track ball roller on a pad too that is not shown in this photo.

Update.

I finally got around to doing this.

First I used my multi meter to read the voltage of the centre "smart" pin with the 240v charger running - was just over 18v. (Different brands have different voltage)

So, using the equation below, I bought the appropriate resistors (55c for a pack of 8) to get from 19V (Vin) to just over 18v (Vout) on the centre "smart" pin & wired them in as per the circuit diagram below. I am using a 12 > 19V converter from eBay to get the required 19v to the +ve side of the plug.

Worked like a charm!! I can now run my Laptop permanently with very little draw - would probably be a bit less if I removed the laptop battery but I'll leave it in case I want to take it out into the cockpit.

Thanks heaps fishmonkey for your post - I'd just about given up!!

How good is the "brains trust" here!!!!!!!!!!!!!!!!!

Similar problems with my HP Pro Book smart charger.

Luckily mine seems to work most of the time. Problem usually is charging it from low battery with the laptop turned off. This usually trips the circuit breaker.

According to my solar regulator the smart charge can pull up to six amps, usually when the laptop is near flat. Guessing the only things that might help are heavier wiring and a bigger battery bank??

Other simple thing is to keep the unit near fully charged and plugged into the charger while in use. This doesn't pull the big amp draw the flat laptop battery does. No problem with the breaker tripping.

No way would I use a cheap inverter. Proven and reliable way to fry electronics!!!!!!