Hooked up 12v 7amp sealed lead acid battery to TP !

[davidwayne34]

I figure it should last at least 6 hours. Anyone ever do this?

Its a heavy bugger, but love the poss. of long duration.

Wayne

[Paul Unger]

How'd you go about it?! We had a discussion going about this here: http://forum.thinkpads.com/viewtopic.php?t=23439, but it kind of petered out . . . I can only speak for myself, but I have to admit I hit the "Chick-n-out Narrows"! I didn't want to fry my laptop. So any guidance you could offer would be most welcome.

[JHEM]

I thought I had mentioned this in the earlier thread, but apparently not.

I used to use "Enerlite" brand 12V NICAD battery packs to power my Thinkpads when I was going to be somewhere for long periods of time that didn't have access to AC.

Originally developed and sold to power portable camcorders, they were rated at 10 amps and would run one of my old 600X machines all day and more using an IBM 12 volt AUTO/AIR adapter.

I've still got three or four of them around here somewhere and will occasionally dig one out and charge it up when I need a 12V power source, although they've long ago given their all and are now only good for a 1/2 hour or so of use.

Regards,

James

[Nolonemo]

I think the key feature of JHEM's post is that he put a auto/air 12v adaptor between the battery and his Thinkpad.

[bill bolton]

I think the key feature of JHEM's post is that he put a auto/air 12v adaptor between the battery and his Thinkpad.

Yes!

There definitely needs to be some current limiting device between any external battery pack and the ThinkPad. This will ensure that a failure in the ThinkPad's internal power management circuits doesn't lead to discharge of the external battery at its maximum energy yield rate.... which even for a 12 Volt, 7.0 Ah gel-cell battery could amount to 150W+ for a short time! (see http://www.power-sonic.com/ps-1270.pdf)!

The auto/air adapter will limit the energy delivered to ~72W maximum.

Cheers,

Bill

[davidwayne34]

What I like about this 12v battery is that it is much smaller and
lighter than a standard car battery. It is only about 4 x 6 x 3 inches and is completely sealed like any standard small battery pack. I have another older laptop to test this on and will report on how it goes and how long it lasts. I think it may not even be necessary to add the car adapter to regulate the watts.

I just cut the laptops power adapter and hooked it up to this 12v battery.

[Nick Y]

Wayne: What laptop model are you using?

[davidwayne34]

I have been testing the battery on my acer 600 mhz laptop and on my TP T22. It works great.

The battery lasts at least 5 hours under continuous dvd playback.

It is great to be able to pay around $8 each for these batteries and have such a long duration.

The only caveat is that I dont know exactly when it is going to poop out and suddenly after hours of use, the laptop turns off without warning.


These batteries last at least 5 years to with no memory effect!