Verifiying Battery for Portable Notebook Computers

[CHD01]

I have a Compaq Presario Model 1650 computer with a battery that I think needs replacement; but it could also be that compter battery meter is in-correct and cauing computer to alarm and shutdown. I have a Lithium battery and a replacement is like $130.

What is the best way to determine if a battery is bad or not? Is there some way to re-condition a bad battery?

I have tried dis-abeling all power saving features and have repeatedly tried to recycle the battery from no charge to full charge. The computer meter I've managed to get up to 100% charge. But if I let it sit for 2 days it drops to 80 or 90% and if I run if on battery it runs out of charge per the meter and alarms. Yet if I try to re-boot, it alarms and the screen will stay bright for up to an hour before the computer really runs out of power. This is why I'm not so sure the battery is really the culprit? The more you learn, the less you are certain of.

 

[Johnl99]

One of the problems that LiOn exhibits is heat dissipation. It "sounds" like that is what is going on with your battery. If the LiOn battery is not cooled properly by the laptop, then the internal charging circuts tend to fail quickly. I have owned 2 laptops that suffered this syndrome. They can be charged to what appears to be 100%, but they will not last more than 15 or 20 minutes of run time. Your Compax 1650 is one that lays flat on a table, and is likely to not shed off the heat that reaches the battery. Buy the new battery, and then place a book or other item under the back of the laptop, and see if you can keep the new battery cooler with air movement.

 

[CHD01]

Thanks I'll try it. The charge indicator on the current battery by the way, never goes over 25% (no matter what the laptop meter says nor how long I charge it) The more you learn, the less you are certain of.

 

[IRstuff]

Most laptops have deployable feet in the back that tilts the back end up. This would be slightly more elegant than having to bring an extra book with you ;-)


The HP laptops have internal fans that provide on-demand cooling. Maybe that's an option if it's a heat problem TTFN

 

[CHD01]

Yes, I have the feet to deploy. I'm just concerned how long ANY battery will last - because I must charge this battery in the laptop - I do not have a separate external charger. I guess that is the worst thing I can do - right? Why doesn't Compaq have a solution for this - seems like their fault! The more you learn, the less you are certain of.

 

[IRstuff]

Does your battery meter have a calibration mode?

On the HP, the battery meter runs through a rather longish routine to calibrate the meter to the battery. If you want a half-way accurate estimate of battery life, you'll need to run the calibration. If the laptop does not have a calibration mode, it might explain the problem with incorrect estimate of battery life.

Even then, it's still somewhat of a crap shoot in any case, since batteries do have individual quirks.

TTFN

 

[Johnl99]

Another thing you can try is the following sequence to see if the laptop battery situation circuit is not operating correctly or if the smart battery is the problem.

1. Start your laptop, and immediately drop into the BIOS setup.

Don't make any changes to the BIOS settings !!

2. Insure that the laptop is unplugged from the wall, and let the laptop run until it completely shuts down while in the BIOS mode. This will not harm the laptop, and you will not lose any information or data.

3. After the laptop has shut itself down from a lack of power, plug your laptop adapter back into the wall, leave the laptop OFF, and let it charge for 12 hours. Try and be as close to the 12 hours as you can.

4. Restart the laptop, and check to see if the Windows OS, and Compaq APM have re-sync'd. Then unplg the laptop and see if how long the battery last's.

Just a chance, but this is one of the procedures that we use to re-calibrate the power values between the laptops circuits and te battery circuits.

Again, don't make any changes in the BIOS.

 

[Polaris2203]

I have the same problem with my Presario 700. The battery self test never shows more than 25%, and when running on batterys the laptop claims only to have 8% left, drops to 0% within a few minutes and goes into hibernation mode. However, if I disable the hibernate and standby options, the laptop will run for around 3 hours on 0%!

Recalibrating the laptop to battery, as per the instructions has no effect. I've tried the bios trick, and just a few minutes ago I tried to break into the battery to disconnect and reset the 'board', but I couldn't get into the thing.

I'm now convinced that it's the battery's onboard circuitry that needs calibrating but it's proving a tough nut to crack. Anybody got a chain saw?

Ian

 

[EngineerDave]

Does heat really play that much of a role on battery life?

If so I'm going to get that cooling pad (from TigerDirect or another place) for my HP ZT1175. The battery life seems to be shorter than I'd like, of course I don't use powersaving, and I like playing music while I work on it.

A program comes up all the time wanting to calibrate my battery. I've done it once, but it always wants to do it again, so I set it back another 15 days each time.