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Powering a Laptop PC
By BT Humble, Section Remote Living Posted on Thu Feb 24, 2005 at 10:52:30 PM MST
Running a laptop more efficiently

The other day I was given an old P166 laptop with a dead battery. I did a bit of testing with it last night, and it seems that its power brick doesn't cope well after a few hours running on my inverter (it gets hot and doesn't produce adequate power). It was bad enough that I had to switch off the screen in order to run the hard drive and CD-ROM simultaneously!
After a bit of thought, I cracked open the case on dead battery and noticed that it contained 10 NiMh cells, which coincidentally equals 12VDC. I removed the cells, soldered some jumper leads directly to the now-empty pack's output terminals, shoved the battery back in and hooked it up to a freshly-charged 12V battery.
Eureka! Everything works just fine, and I also don't have the power losses associated with taking 12VDC, stepping it up in an inverter to 230VAC, stepping it down in the power brick to 19VDC, then having the laptop run it through a regulator to get 12VDC.
My inverter was drawing 3.2A from a 12V battery to run it, while this configuration only draws 2A. Quite a saving!
BTH

Powering a Laptop PC | 11 comments (11 topical)

Direct connection (3.00 / 0) (#1)
by wdyasq on Thu Feb 24, 2005 at 05:00:43 PM MST

All of the laptops I have been around will operate with 12V plugged directly into the adapter port. My P133 draws 1A @ 12V, 1.5A booting and 600ma when the screen shuts off.

Ron
Adventure is just bad planning." -- Roald Amundsen

Re: Direct connection (3.00 / 0) (#2)
by BT Humble on Thu Feb 24, 2005 at 05:23:25 PM MST

All of the laptops I have been around will operate with 12V plugged directly into the adapter port. My P133 draws 1A @ 12V, 1.5A booting and 600ma when the screen shuts off.

This one has a peculiar 4-pin adaptor plug, and I didn't want to cut it off the lead. Also, the adaptor puts out 19VDC?

I'm hoping that my old Apple Powerbook laptop will similarly work from 12V, although it seems that its internal battery is 14.4V (and its adaptor is 24V).

BTH

[ Parent ]

Re: Direct connection (3.00 / 0) (#5)
by ghurd on Fri Feb 25, 2005 at 06:01:49 AM MST

The Apple 14.4 battery, 12 cells, is probably rated to go down to 0.9v per cell, or about 10.8v. It should be happy with 12v.
G-
Ghurd.info
[ Parent ]

Re: Direct connection (3.00 / 0) (#6)
by BT Humble on Sun Feb 27, 2005 at 02:20:23 PM MST

It's always worth a try!

BTH

[ Parent ]

Re: Direct connection (3.00 / 0) (#7)
by ghurd on Sun Feb 27, 2005 at 02:49:39 PM MST

I would 'cook it'... I mean, 'Try it'. US$1000 of someone else's money is not that much...
LOL.

If the power input to the battery in terminals is less than it can take, I think it will just act like the battery is VERY low. Anyway, I can't see it burning anything up.

(and I did the North American 'Mister Magazine' computer power supply!
Oooo. Ahhh. Ohhh.
Being in N.A., I said 'Mister What'?
They told me I was important... at the time...
Mr. Who, again?
I guess the men like it more than the ladies)

Anyway, if the battery is big-time low voltage, I don't see how that will cook the rest of it. So 12v+/- should not kill it.

G-
Ghurd.info
[ Parent ]

Re: Direct connection (3.00 / 0) (#8)
by BT Humble on Sun Feb 27, 2005 at 07:30:59 PM MST

;-)
BTH

[ Parent ]

Re: Direct connection (3.00 / 0) (#9)
by ghurd on Mon Feb 28, 2005 at 07:12:06 AM MST

LOL. Spilled my coffee!
G-
Ghurd.info
[ Parent ]

Re: Direct connection (3.00 / 0) (#10)
by ghurd on Tue Mar 01, 2005 at 06:59:18 PM MST

They told me it was the #3 circulating mag Down Under. Maybe I didn't hear the fine print.
Like playboy, but upside down.
G-
Ghurd.info
[ Parent ]

Re: Direct connection (3.00 / 0) (#11)
by BT Humble on Thu Mar 03, 2005 at 03:00:28 PM MST

They told me it was the #3 circulating mag Down Under. Maybe I didn't hear the fine print.
Like playboy, but upside down.

Don't make me show you the bunny again! ;-)

BTH

[ Parent ]

Re: Powering a Laptop PC (3.00 / 0) (#3)
by dconn on Thu Feb 24, 2005 at 05:35:06 PM MST

I do the same thing - connecting the notebook battery connectors to big batteries. Its amazing how well it works. I have a "Gateway Solo" 333Mhz notebook (that someone I know broke the LCD screen on) connected this way to a 12V battery array and it works fine (shuts down at about 10.5V) - whats a bit surprising is that the battery pack in the notebook originally was 16V but its happy with 12V anyway

Derek

Re: Powering a Laptop PC (3.00 / 0) (#4)
by jimjjnn on Thu Feb 24, 2005 at 07:10:29 PM MST

I too have a Gateway solo 9300 Pro and power it off a 12 volt Nicad that my daus gave me when the worked for a med machine mfr. It runs all week on the batt without recharging and I leave it turned on 24/7. The original NIMH batteries only lasted 6 months and died. Gateway replaced them twice, no charge. It was then out of warranty and I didn't feel like paying 178 bucks US for a new battery
Denver,CO
[ Parent ]

Powering a Laptop PC | 11 comments (11 topical)

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