Can't boot Latitude 5500 without power cord


I have a Dell Latitude 5500 laptop. With the power cord connected, it boots and runs fine. Once booted, I can disconnect the power cord and run from the battery for a few hours. No problem.

However, I cannot boot the machine when running on the battery, even when the battery is fully charged. I get the kernel selection screen, but the encrypted drive password never comes up. I just get a blank screen.

If I connect the power cord, it boots just fine. If I disconnect the power cord while it is running, the system runs as expected on the battery.

So, my battery is fine, and I can run with the battery as expected. However, I cannot boot when on battery power.

When I first got the laptop, it had Windows installed. When Windows was installed, it booted on the battery without a problem.

This is the strangest thing. Any ideas?

Thank you!

It seams you not the only one with this issue.

Thanks. I looked at that and the bug report. I tried what they suggested, but it didn’t help. I still can’t boot from the battery.

Problem solved. My system had BIOS version 1.7.4 installed. I updated it to 1.20.0, and everything works! No need for any of the other workarounds described elsewhere.