Question : Problem: Dell Latitude battery is not fully recharging

Hello,
I have a Dell Latitude D830 that is less than 2 years old. I almost always use it plugged into AC power through a port replicator. At one point, I found that the original battery was completely discharged and would not accept a charge. I replaced this battery with a Rayovac replacement. Initiallly, the replacement battery showed 100% charged in power meter. I fully discharged and recharged per recommendations. The maximum recharge, according to the power meter, was then 95% or so. Subsequently, the battery continued to recharge to a lower and lower percentage. Power meter always indicates "Charging" even after turning the machine on after being off overnight. Again, I am on AC power at all times. Currently, Power Meter shows only 54% power remaining. It appears that the laptop is somehow reducing total battery capacitiy over time. I also suspect that this is how the first battery was ruined.

How can I isolate the cause of this problem and hopefully rectify it? Is there any diagnostic tool that would be helpful? Thanks iin advance for any help.

Answer : Problem: Dell Latitude battery is not fully recharging

As far as I know, the metering circuitry used to be inside the batteries themselves, interacting with some corresponding device on the mobo. It just may be that these non-Dell batteries don't talk the right dialect, or are they Dell-approved?

The charging circuitry is on the mobo, yes. If it can be proven bad, it's unfortunately new mobo time. However, trying with a Dell battery may be a good step to take before this...

Measuring the power brick involves checking the output voltage against the nominal (noted on the brick, usually 18 - 20 VDC), but it has to be measured under load to be of any use and that might be a bit tricky if you're not used to that sort of thing. Basically, you need to connect a resistor of about 5-10 ohms (depending on the Current (A) or Power (W) rating of the brick) to the output and then measure the output voltage. Since the resistor will eat all the power that would otherwise go into the laptop, it'll become hot quickly. A 25 W type should last long enoug for the voltage measurement.
/RID