Compaq Presario not charging battery...

Check the charger circuit with a DVM to see if it is putting out voltage to the battery. If so, the battery must be replaced.

Most of the time, the failure in this case, is a defective battery.

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JANA _____

A friend of mine has a Compaq Presario1200 which apparently has stopped charging the battery. The mains power LED and battery charging LED lights up when connecting the mains. However when I pull the mains plug the computer shuts down immediately as if there was no battery at all. Same behaviour with a brand new battery.

Any hints or tips highly welcome

regards

Chris

"JANA" skrev i melding news: snipped-for-privacy@uni-berlin.de...

As I said, we have tried with a brand new battery too, same result. I mainly wanted to know if there is some kind of fuse or something in the Compaq notebooks power supply management which may break in certain situations. With all components being SMD it not much one can do without proper equipment if there is a component failure.

Any clue how much a new powersupply (which I assume includes the charging circuits, may cost?

Chris

: Any clue how much a new powersupply (which I assume includes the charging : circuits, may cost?

: Chris

Google is your friend.

I google searched "multi voltage pc laptop power supply" and got many hits. One was:

b.

Assuming this is a reasonably recent laptop, ie newer than about ten years old, the power supply is almost certainly just that and nothing more- a power supply.

The management of battery charging is taken care of by the laptop circuitry, not the PSU. If the power supply is powering the laptop normally, the power supply is most likely OK.

There are usually surface mount fuses inside laptops, and it's possible one has blown. However, more likely the charging circuit has failed because of a bad battery with shorted cells. Repair may well be uneconomical or impractical.

Dave

I beleive he ment the internal power supply..

The Compaq power supply just supplies 19V dc at 2A -3A. The charging circuits are on the motherboard. The battery pack has a battery guage circuit which monitors and records the amount charged or discharged and sends this info when queried by the PC over the SMBus/I2C.

Had the same problem with a Presario 1200XL405 notebook. Tried the same solution, new battery pack but still would not charge. Worse, the notebook would occasionally shutdown as if it lost power suddenly when using mains supply without a battery plugged-in. When a battery is plugged-in, it slowly gets discharged even when powered by mains.

Finally, built a NiMH battery charger based on the MAX712 datasheet. Used the Presario's 19v power supply as the supply for the charger. Hacked a switch with 3 flat prongs which fit into the battery contact slots as the output for the charger. Removed the innards(spring + pilot lamp + rocker contact) of the switch.

The charger is fixed for 8 cells at about 1A charge rate as the battery pack was 9.6v 4000mAh. The MAX712 can be programmed for 1 to 16 cells.

This was a cheaper solution than a motherboard swap.

/bledge 14 Nov 2005

My Compaq 1610 always had battery problems of one sort or another. One more thing to consider is that Compaq may have a power management driver upgrade/fix available for your model. Check under support on the Compaq site. They had a software fix that actually worked in my computer. Also some Compaq models have the power management circuit available as a replaceable part.