Thinkpads Forum

Is there any reason I couldn't use an old battery pack to make a 12V adapter for a 600? The battery pack is 11.8V. I'm thinking auto use or connecting straight to a gell cell or car battery for field use. I know I wouldn't want to connect to a cigarette lighter with a running engine as the alternator may spike up to 14V, but with the engine off no more than 12V would come through. Of course a 12V regulator could be put in the old battery case, but I don't know if an electronic regulator set at 12V would pass a full 12V through. Of course if it's only a .5V voltage drop that would work. How much voltage does the 600 really need though? How much does say a half depelted battery drop, or do LiOn cells not drop as they deplete???

http://search.ebay.co.uk/laptop-car-ada ... rlinkZintl

*shrugg*

Well, the difference is the auto adapter has to jack up the voltage to 16V which then feeds the built in DC power supply, which drops volatage back down to 12V. I was thinking it would be more efficient to skip the conversion in between, but maybe not worth the effort.

farna wrote: but maybe not worth the effort.

bingo.

Actually, you can directly suppply power through the battery terminals.
I am doing this on TP-770X. The voltage can be as low as 10.8V as
written on the battery pack. (In fact, I'm running my TP-770X with 10.5V
with no problem at all.)

This may be a big deal for some situations. For example. let's think about
using your laptop in a car. If you put the laptop in stand-by mode while
the car is not running, the laptop needs pretty small current just to hold
the memory contents. However, if the laptop is powered by an inverter,
the inverter may drain comparable to or even larger current than the
laptop stand-by current fom the car battery even when the laptop is in
stand-by mode, leading to significant voltage drop after some time
elapses.

Don't ask me how to power your laptop directly through the battery
terminals. You will have to experiment by yourself, including making
an external power regulator by yourself. I hesitate to give you any more
specific info because the circuit design should be dependent on your car
and laptop, and I can't take responsibility for any possible trouble.

One more thing. This direct power feeding does not help you updating
the bios without a battery pack, because the bios update program tries to
communicate with the battery pack to identify it. When I run my laptop
by supplying 10.8V directly into the battery terminal, the laptop thinks
that the power is from an AC adapter.

Just one question shined -- are you simply feeding the voltage to two terminals on the 770? The reason I was asking was not to use the laptop in a vehicle but directly from a car battery. I know the kid I'm sending the laptop to doesn't have power in their home (near Davao, rural area), but does have access where the laptop can be charged and will be used most ofthe time. I have been looking at solar battery chargers in the 5-10 watt range. Would take all day to fully charge a medium sized car battery, but a fully charged car battery should power a laptop 10-12 hours, at least 8 hours even using the DVD/CD a good bit. Don't know how long a normal laptop battery in good condition will last with the DVD, but I'd assume it will play an hour long movie at least. I bought a reconditioned battery that seems to be working well for now, and the one I got with the computer will last 40-45 minutes. I bought a 12V car adapter, and will get a set of clips wired to a socket. That's just so inefficient since voltage is boosted to 16V then dropped back down in the TP power supply again! Should have been a direct 12V input on the thing like on my older HP laptop. Since the 600E only wants 10.8V I might be able to put an electronic regulator set at that amount in an empty battery case.

I bought a soldering iron about six months after I bought my first computer, a Tandy TRS-80 Color Computer 2, back in 1984. I modified it heavily, ending up with one Color Computer 3 (a whopping 512K and 2 MHz!!) torn down and mounted in an old Tandy 2000 case complete with a pair of 5.25" floppies (software configuered to think they were four single sided drives), a 3.5" floppy, and a SCSI hard drive; and one CoCo 3 mounted in an old Kaypro II luggable case modified to use the Kaypro monochrome monitor. I'd intended to mount a gell cell in the Kaypro case and make it truly portable, but the CRT would have eat up to much power. Not much point in making it portable for only an hour! It wasn't a light weight either, so more than a single 12V gell cell (as used in emergency lighting, about three pounds) was out of the question!

If there is anything you can add shined feel free to send me a PM or e-mail (farna@att.net).

farna

I'm just feeding the voltage to two terminals. Nothing more. In fact, I don't use a
battery pack at all. The power lines are directly soldered to the battery terminals
on the system board side.

The voltage can be at lease 10.5-12.5V in my system. My TP-770X works just
fine between this voltage range. I'm afraid of causing any permanent damage so
I have not explored any further range,

Your idea of driving a laptop with a car battery sounds like an interesting project.
Hope your good luck.

My plan is to mod an old battery pack and just run wires from it. I thought about just running the wires directly, but on the off chance that someone connects it to a running vehicle I think I'll put a voltage regulator in the battery pack and wire it to supply 10.8V (if I can get that from 12-12.5V -- should). I'll use a big heat sink on it, and thought about drilling holes in the battery pack for ventilation, but there won't be any air flow under the laptop anyway. I can put a note in with it (I'm sending it to a foreign student -- in the Philippines) to prop the back up on something, but may as well put in a note to make sure it isn't connected to a battery in a running vehicle. I can put that on a lable on the batt pack.

I'm planning on buying one of the "jump start" rechargeable battery packs. There are some cheap ones around here for $29.95 with a 300A, 12Ah gell-cell battery. I wonder how long that would operate a 600E? I think the original battery pack is 3.6Ah, but then its only 3600mA as well. Just going from the Ah rating the gell should last at least three times what a battery would -- so maybe six hours with some use of the CD, 3-4 with heavy use (like playing DVD movies).

I'm investigating a solar panel to recharge the thing. Planning on a 10W panel with a 3-6A charge controller. I haven't found any stand alone chargers for a TP600 battery on e-bay, so assume they either weren't available or very rare -- which would equate to $$$$. I did buy a refurb battery that seems to last at least a couple hours when charged, but the external pack is going to be the most practical in this situation.

please let me know how this works i'm very intrerested in knowing if the 600e can handle this kind of a mod
thx

Mainly due to time to send the thing off I have decided not to do try this. There's no reason it shouldn't work, and there are enough dead battery packs around to rob for connectors. I'd just use a solid state regulator to drop to 10.5-10.8V just to be sure. Should handle a steady 12V DC easily, I just wouldn't connect directly to anything with an alternator or generator without some kind of regulation down to a steady 12V. A car battery might top out at 12.5V or so, but a generator/alternator doesn't cut out until 14-14.5V.

Farna,

I am late jumping in here, but I can assure you what you spoke of will work. I had connected a 12V 2.0AH Lead Acid Battery (SLA) directly to the internal connectors of an old battery pack. This old pack was dead, so I broke it open, pulled out the cells, and connected a short jumper set to the internal connectors. I then put a nice quick connect at the end of this lead. Then I made a another similar but reversed (male/female) quick connect on the battery. I duplicated the battery pack link to a small power brick that was made to recharge the sla style battery. I could get a full charge, trickled, overnight.

The system ran fine, just never did figure a way to use the 'smarts' of the battery pack to actually monitor the sla.

I never did a true run test on it, however normal use, email, web browsing, and some office stuff, I got easily 2 hours out of that. It is a challenge to run it with no 'fuel' gauge....

The concept is good and does work.

One interesting note. I also tried plugging the SLA into the power port on the back that normally has the IBM power brick connected. That was shaky at best. The power there should be IIRC around 14V. So as the battery lost power, the screen would get flickery. I figured the DC/DC inverter on the mobo really wanted a bit more juice.

Good mod project!

well, the only reason I'd put a regulator in the battery pack shell is just in case someone connected it to a battery (or cigarette lighter plug) while a vehicle was running. That would throw up to 14.5V into the laptop and could cause a problem. As long as it's just a battery it would only be a max of around 13V, usually 12.3-12.5V max, and it would be steady. An alternator or generator could spike. For my personal use it wouldn't be a problem, but doing this for someone else.