Computer question....

takza · Post by **takza** » Fri Dec 31, 2004 12:50 pm

I have an old Thinkpad 365X that was given to me...boots and works OK except for the battery...which doesn't last long at all or hold a charge. Also the hard drive is running in DOS mode (driver issue)...but it works well enough.

Two questions: what wattage level and kind of 12V to 110V converter would I need to run it from the Tercel's battery? How pure does the sine wave need to be and would there be possible current surge issues?

Would it be possible to run it while driving if it was on a padded surface? Or would the hard drive bite the dust from the shock & vibrations?

Since I have nothng in it...it would be great for travel & camping...could save info and topo maps for various areas...etc.

PS.....Don't mind Bart...he's PO'd about something....then he left....

sacwac · Post by **sacwac** » Fri Dec 31, 2004 7:01 pm

For just the laptop, I would imagine you would need at least a 100W inverter. You could do with less, but you might want some headroom.The kind that wires to the car battery, not the cigarette lighter. I've run a pentium 3 1Ghz, from an inverter that didn't put out any kind of sine wave. Most of the cheap inverters use pulse width modulation. The one I had was about $30 a couple years ago.

There is always the possibility of a power surge, but from the cars electrical system, you have the inverter, and the laptop power supply, plus the internal laptop power supply in that line.

Last time I had a computer in the tercel, I just tossed the whole case into the trunk, with no padding at all. It worked just fine for the few months that I had it. Never hurts to use some padding...

icE · Post by **icE** » Fri Dec 31, 2004 8:01 pm

You can use any type of cig lighter adapter, at least 50W or so continuous, it doesn't take much to power a laptop, depends on the model i guess. But it should work just find on a standard power inverter, because i ran a small TV (13 inch) from my 125W continuour power inverter in the car with no probs whatsoever. I wanted to use a laptop and mount it in the dash to use to play DVDs, and second as a navigation system, and an mP3 player and hook it up to the AUX input on the headunit, that'd be sweet

Adelard of Bath · Post by **Adelard of Bath** » Sat Jan 01, 2005 1:01 am

My dad used to be a harddrive engineer at IBM (back when they made hard drives) and they sent him to Japan a couple times to help them out...they were designing their laptop drives to withstand such-and-such g-forces from dropping the laptop from whatever hight...it was crazy the number he was saying...until he's like "Hey, uh, there is no way the rest of the laptop is going to survive that..." and suddenly everyone was like "okay good enough"
So. If you hit huge bumps, it will probably "interrupt" the heads on the hard drive momentarily, but they are so fast, they will find their spot before you even know what happened. That's even assuming the hard drive was doing anything difficult while you hit the bump.

For power, you could consider this: what about finding out what voltage that battery is rated, and wire it directly into the car? Just searched the web, found that power supplies for that computer are rated at 16 volt outputs! The battery in your computer is a mere 9.6 volts. A 16 volt supply will load down somewhat with a load on it, but the ones I saw were rated at 3amps or something like that, so from all this info, I would say with fair certainty that you could wire the +12 from the car directly into that little jack on your computer, the one that your power supply plugs into. This way, not only would you eliminate the inverter to step your voltage up to 110volts (with its associated noise), but you would ALSO eliminate the transformer necessary to drop the voltage BACK DOWN to (ironically) where you started from.

takza · Post by **takza** » Sat Jan 01, 2005 2:23 am

Thanks for the responses....

This doesn't have a CD in it...though I have an external CD I can use to transfer data with.

Best bet would probably be using an inverter to filter the current some...though a lower powered one might have a problem dealing with a failing battery?

There is one for sale on Ebay for $49 that is supposed to work OK....so they aren't in high demand.

I might get some use out of it.......

takza · Post by **takza** » Sat Jan 01, 2005 1:03 pm

After a web/newsgroup search I've found that there are maybe 2-3 options...

* there is a car/air adaptor converting DC input to 16VDC as needed. $50

* there is the 12V to 110V inverter. $30

* have found that trying to connect directly to 12V car battery would likely run a lot of current into a failing battery...maybe causing the BIG BANG....since the wall trans is limited in amperage output. One guy used a resistor to reduce the current flow from a car battery though. $??

The inverter will use almost 2Xs the current that car adapter does.

Adelard of Bath · Post by **Adelard of Bath** » Sat Jan 01, 2005 2:39 pm

And the car adaptor will pull more current than the direct connection to the battery....look at it this way:
Any time you have a "black box" between your battery and your computer, that "box" will waste power. If electronics aren't your strong point, you might be getting confused with all the "current" and "voltage" and "resistance" and "power" numbers...but the truth is, they are all related, and it all boils down to power. Power. The power your computer takes, vs the power your alternator is capable of putting out...i.e. watts. So, if you connect the battery directly to the computer, it will use x-number of watts....lets make up a number like 10watts, I have no idea. Your computer will always use 10 Watts no matter what way you hook it up, that is just what it takes to run the chips and the harddrives and the screen.
Now if you hook it up with the car adaptor, the computer will use 10 Watts, and then the adaptor will use an ADDITIONAL whatever it uses, something small.
If you instead use the inverter and the wall-supply that came with the computer, the inverter will use some Watts, and the wall-supply will use some Watts. Which means that you will have the 10 Watts the computer uses, PLUS the x-Watts the interter uses, PLUS the y-Watts the wall-supply uses.

So you can see that the least power usage will occur from directly connecting the computer to the battery. Just make sure not to leave it on or it will drain the battery! You could hook it to an accessory switched line I guess

Remember, the "10 watts" number I threw out was just for example, I don't actually know how many watts the computer will burn. But I'm sure it will be WAY LESS than headlights, or heater fan, or rear defroster.

Oh and if you put a resistor in-line, that will just burn power. You definetely don't want that! Burning power within the resistor?

I've built alot of battery chargers for fun cuz I can never find one that suits my needs, and I've never had a problem with dead batteries pulling too much current; in my experience, they just don't hold a charge...you know what you could do, is go to the car parts store and get one of those cute blade-fuse holders with a wire coming out of each side of it...then put that in your connection to the computer; that way if the computer or the battery started pulling too much current, the fuse would blow, and the worst case scenario would be the computer starting to run off the internal battery and you would get a warning on the screen that your battery was low.

takza · Post by **takza** » Sun Jan 02, 2005 4:24 am

Here is something found on the newgroups.....

"Make a first test only with A and V meter.

At my last notebook, on the power supply was written
12..19 V. So I thought it is possible to connect direct
to 12 V.

The original power supply had two modes:

19V for the computer, not charging
1.5A constant power for computer while charging
batteries.

The trick was: when I connect a fresh charged
car battery with 13.9V, and computer starts charging
internal batteries, he connects direct the incoming
voltage to the internal 9.6V batteries.

In this case.... 9A instead of 1.5A are going....

So make no experiments before Your carefully
understand how the power supply works.

I solved the problem at my old notebook with
a 0.5 Ohm resistance."

With this notebook I have a 9.6V battery and a 110 V transformer rated 16V and 1.88A out.

I understand that these transformers are rated higher than the battery charged. I have another one rated 15V for charging a 12V battery. A car's alt can put out 15V?

I'd like to avoid the hassle and expense of the inverter..but if the battery goes in some way or I fudge the laptop electronics...then I am up the creek. With an inverter I could use it for other stuff...like charging a spotlight, drill, or shaver.

Maybe going thru an inverter might add an extra 60-70 % current use vs the internal battery...someone posted their test results...forgot to copy them.

Adelard of Bath · Post by **Adelard of Bath** » Sun Jan 02, 2005 1:39 pm

Well now that you have me thinking about it, I bet if you had an inverter...you would probably find more and more uses for it all the time! First your shaver...then something, then something else...heh soon you will be running your damn TV and DVD player at the camping spot! hhehhehehe
and a fridge, and a microwave....better get a huge inverter.

Paul · Post by **Paul** » Sun Jan 02, 2005 7:45 pm

Just saw this auto adapter on Ebay:
<a href='http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 04073&rd=1' target='_blank'>ebay thinkpad 365 adapter</a>
The Thinkpad is a pretty tough computer. Itronix also makes some tough laptops... some were built for mobile use.

takza · Post by **takza** » Mon Jan 03, 2005 6:29 am

Adelard of Bath wrote: Well now that you have me thinking about it, I bet if you had an inverter...you would probably find more and more uses for it all the time! First your shaver...then something, then something else...heh soon you will be running your damn TV and DVD player at the camping spot! hhehhehehe
and a fridge, and a microwave....better get a huge inverter.

I can see it now...one of those small trailers with a bank of batteries and a big inverter humming away....stuff lit up all around...scaring away my animal friends....modern day camping?

takza · Post by **takza** » Mon Jan 03, 2005 6:37 am

Paul wrote: Just saw this auto adapter on Ebay:
<a href='http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 04073&rd=1' target='_blank'>ebay thinkpad 365 adapter</a>
The Thinkpad is a pretty tough computer. Itronix also makes some tough laptops... some were built for mobile use.

That's a good price compared to what I've seen elsewhere......and probably reliable. Thanks.

Adelard of Bath · Post by **Adelard of Bath** » Sun Jan 09, 2005 7:53 pm

Takza, I thought of you and your camping needs when I saw this in the latest Harbor Freight catalogue...

<a href='http://www.harborfreight.com/cpi/ctaf/D ... mber=45381' target='_blank'>http://www.harborfreight.com/cpi/ctaf/D ... r=45381</a>
It is a 20kW generator powered by a Detroit Diesel engine! 12v electric start, water cooled, 3-phase even, only 2.4 gallons per hour!
At least it would keep bears away!

takza · Post by **takza** » Mon Jan 10, 2005 7:06 am

I could put that on a trailer along with my bank of batteries and the big inverter....bet them damned animals would stay away then!

Serves 'em right...fer not liking machines...... :rolleyes:

What will humans think of next?

Adelard of Bath · Post by **Adelard of Bath** » Mon Jan 10, 2005 11:22 am

Laser-beam perimeter? Motion sensors? Make sure your trailer is big enough for a jacuzzi for relaxin in the back country hehehhehehhehhe

I must be doing it all wrong with my 12-pound pack when I go out!