Notebooks & Netbooks

[Navvy]

Acer Aspire 5535

Battery will not charge.

Mains power keeps the laptop running without running the battery down, but battery does not charge.

If mains is unplugged, the laptop runs on battery (but runs it down).

System Tray icon shows battery state, but indicates mains is not connected (when it is).

PSU voltage checked with a voltmeter. 19.1V

Voltage also measured on motherboard, so plugs, sockets and wiring are all OK.

Tried another PSU with exactly the same result.

Looks like the BIOS is failing to recognise the PSU and therefore not using it to charge the battery.  I know that some Dell laptops do this, but they show a warning message to explain the problem.  There is a chip in the Dell PSU which provides identification, and some non-genuine PSUs have a chip fitted in an in-line adaptor.

Having read about BIOS problems that might be related, I looked for a BIOS update.  The existing BIOS is 1.04 and no update available.  I downloaded the 1.04 version to re-flash in case of corruption, but the update refuses to run unless the mains is connected.  The mains IS connected, but it isn't seen so I can't update!

The CMOS battery was low, but not dead.  I replaced it.

I charged the laptop battery from a bench power supply, taking care not to overcharge, and the laptop is working fine so long as it is always on mains to prevent the battery running down.

Edited to add that laptop will not power up without battery installed, or with very low (3%) battery.  That's why I charged it to 77% on a bench supply. Battery has good capacity and runs down slowly as would be expected when mains is removed.  System Tray monitor is showing the battery state correctly.  Laptop has always been used with mains connected - effectively using the battery as a UPS.

Has anyone seen any similar problems, or have any suggestions?

[Acer-Ryan]

It sounds like you have went through a lot troubleshooting and tests. This problem looks to be a problem with the mainboard itself not the software/firmware of the BIOS. If the unit was working properly on this BIOS previously, then I believe its a problem with the mainboard. I would recommend service through your regions Acer service center.

[Navvy]

Thanks for responding, Ryan.

So this is not a recognised bug.  That is at least useful to know, since I had seen several reports of batteries not being recognised by the BIOS on some Acers.  

Should the motherboard be capable of charging the battery from any PSU, or does it use an identification chip?  One PSU that I tried was a straightforward adjustable adaptor that I set to the correct voltage.

There were file corruptions - particularly one in the Windows Genuine Advantage system that blocked it from receiving any Windows Updates.  I fixed that, but I didn't know whether there would be anything else that could prevent PSU recognition.

The laptop was running Vista, so it'll be out of warranty.  I think the owner was going to just replace it and not buy Acer next time.  At least I got it going enough for them to be able to transfer their files.

[Navvy]

Is there a diagnostic self-test program available that can report on charging faults in the motherboard?

[Acer-Ryan]

I apologize there are no diagnostic programs that I can suggest or that I can provide you to use.

[Navvy]

Thanks Ryan - that seems very surprising.  I'd have thought that power supply, charger and battery diagnostics would have been a very basic requirement for any laptop.  The voltage and current measuring devices must be on the motherboard for the battery monitor to work.