Sometimes I use a laptop to get to the S dope. I have recently found something out. The battery usally lasts about 50 minutes - maybe 1 hr depending on the monitor brightness and the amount of harddrive usage, but yesterday I disabled the mandatory standby at 3% remaining and decided to see how far I could run this on empty. I got 90 minutes on it then the laptop went into some other mandatory shutdown that I didn’t know exist. The laptop uses a NIMh battery.
My laptop battery lasts about 3 hours, which I have found to be true. Yesterday my AC converter cord got a broken wire and now I can’t charge my battery. I went to BestBuy and CompUSA to get a replacement AC converter cord but the ones they have there didn’t work on my Dell Inspiron 3000 or maybe there are more problems than the cord so now I am going to have to ship the laptop back to Dell for repair. I am living in an extended stay hotel while looking for work in Fort Lauderdale and my laptop was my connection to the net. So yesterday I had to go to my storage locker and pull about 1/4 of my furniture and belongings out till I could get to my desktop computer and pull it out. So now I have my desktop computer (even the printer/fax) set up in my hotel room and everything is right with the world for the time being.
I used about an hour of my laptop’s battery looking for replacement cords on the web, an hour to transfer everything important to my desktop and I have about an hour left in case I realize I forgot something, but later today I will be mailing it to Dell. Fun stuff.
It is so easy to recharge any battery (if you know what you are doing).
If you have any source of AC just get a diode and a resistor that will limit the current to whatever you want it to be. Just make sure you keep the current at a level that will not damage the battery.
You can also charge it from a DC source easily.
My laptop has one rechargeable 9V NiMh and I use it plugged in 99% of the time so it is not worth to buy another one. If I will be on a long trip where I cannot plug in anywhere I build an 18V battery pack with D cells (12 of them) and feed the computer through the adapter connector (the adapter supplies 18V). For ocassional use Alcaline batteries give you a much longer use than any rechargeables and when they die, you dump them. Of course, if you run on batteries a lot this is more expensive.
I have not measured it but I guess a battery pack with 12 D batteries will run my computer for about 10 hours, maybe 12. I am just guessing.
I’ll tell you one thing, I’ll find a way to recharge a battery anywhere. 
Power saving is in the Bios & also another way in the operating system. The operating system one uses cpu power.
I have a laptop that has hiberation, its really cool, it sit there for a week, I touch any button presto, in 2 seconds every thing on it is ready.
I often jerryrig power adapters for Laptops. On the bottom of a laptop are the power requirements. Not only do you have to match voltage, but you have to match grounding plug orientation. Thus, I get 14v adapters from thrift shops for a buck, then wire the plug if necessary & they fit my laptops. That way i dont ahve to pay $100 for a universal laptop adapter.
k2dave
There are probably several reasons that you were able to go beyond for so long. Most likely the biggest reason is that the battery charge level indicator is an estimate of the remaining charge on the battery. The computer keeps track of time running vs. voltage level and estimates the amount of charge left. This can be pretty innacurate. So they error on the side of caution. Another reason is possibly to extend the life of the battery, though with Nickle Metal hydride batteries full discharge isn’t a problem, like it is with lithium ion batteries, where a discharge below a certain point actually damages/kills the battery. Still, batteries only have so many charge/discharge cycles before they die. The second shutdown is probably more voltage level based than the first, which is most likely an estimate like I pointed out above. A batteries discharge curve is only linear in a specific range, once it discharges to a certain point, it drains much faster.
Sailor, be cautious using alks, when the device calls for a different battery type. Alcaline batteries have a different power curve than other batteries. Lithium Ion for instence can deliever a lot of current quickly, and if the product needs that kind of delivery, the alk’s might not be able to provide it.
Lithium? I wonder if you lick it if it’ll cure your bipolarity?
that’s funny handy
Narile, say what? A pack of D cells will supply way more than anything any notebook computer can possibly need and more than the AC adapter so I cannot see the problem. In any case, the first thing I do when I get a gadget is measure and study the power requirements.
After reading the above, I am considering building a external battery pack. I can put D cells to total pretty close to the 19V the power cord supplies (method 1) or total 12V and use an inverter to get it to 120vac then use the cord (method 2).
my concerns:
Method 1 - the voltage will start too high as new alks can be as high as 1.8v providing over 21 volts - and what happend when the batteries start to die and only 14-15 volts trickle in?
Method 2 - use the voltage invewrter I got to recharge/use the laptop in a car. Build a 12 V battery pack to supply that. Now I will lose some efficency but i think the inverter can handle the voltage highs and lows ok and just turn off when the voltage is too low and the laptop starts running on the internal batt
k2dave, be sure you know what you are doing. my computer’s nominal outside supply voltage is 18V but will run fine way down to 12 V and even less so voltage is not a problem. By the time the batteries get down there they are dead.
I take out the internal battery because I do not want to be recharging it from the external pack (taking into account the losses).
Using an Ac converter is an unecessary waste of energy.
make sure you understand all these things before you start messing.