Internal battery of an iMac

The battery life rkaufmann87 posts is valid for normal usage. However, its life can plummet if you are routinely cutting power to the computer by breaking its connection to wall power.

The Mac maintains its settings while turned off by allowing a tiny trickle of current around the power supply. This powers any components that must retain information as long as the computer get power from the wall socket. The battery only starts to work if the computer is unplugged from the wall, and is intended for times when the computer is being moved or when maintenance is required. Therefore during the life of a computer the internal backup battery may need to run only hours or days, thus its long life in "normal" use.

If you unplug the computer or turn it off using the switch on a power strip, backup power supply, or "power center" located between the computer and the wall socket, the battery will work overtime and can fail in months, not years.

Turning off the computer through the Mac's "Shut Down..." command in the Apple menu does not stress the backup battery.

Some well-meaning pundits of "green living" who have little knowledge of computers have recommended we unplug our computers anytime we are not using them. By doing so you may save $7 worth of electricity in a year but incur a computer repair of several hundred dollars.

The backup battery is buried deep in modern iMacs and, for most of us, is not a user-serviceable part. Therefore the cost of replacement is a few dollars for the battery but one to two hours of technicians time for accessing it. Around my area they get $40-60 per hour!

rkaufmann's request for actual symptoms is very important because reports of dead backup batteries causing problems do not show up here as much today as they did before Apple shifted to Intel processors in 2006.

Yikes! Well, that explains the PRAM battery question! Did you ever have devices that were on a UPS or a surge protector show damage after a lighting strike?

I have a friend who lost a Windows computer on a UPS to lightning but, too late, he realized that although his power line was protected, his modem cable was not. Newer UPS models usually add protection for modem and ethernet cables.

A dead USB port could be lightning related but have you tried an "SMA reset?" Instructions here:

Reset the System Management Controller (SMC) on your Mac - Apple Support

In dusty conditions an optical drive can accumulate deposits on its lens that cause it to "play dead." When an optical drive stops working the first thing to try is a drive cleaning disk. These go in the drive slot and remove dust from the lenses. Such disk are available in most consumer electronics stores or office superstores that sell computers. Cost in the U.S. are in teh $5 to $15 range.

The slow booting concerns me--it could be a hard drive issue. However we need to eliminate software causes first. A respected and long-serving member of these communities has created a simple utility that will take a "snapshot" of your configuration without revealing any sensitive information about you and your computer. It is Etrecheck, and is available here:

http://etrecheck.com/

Run it and, when its report displays, click Etrecheck's "Share Report" and then "Copy Report" from the resulting dropdown. Paste the entire report into a response to your own thread here. It will allow us to quickly identify or eliminate software as the problem.

Stick with us! We may yet get you some relief!

Symptoms are the computer will not start. From what I have seen, they last over 10 years which is usually longer than most owners keep them.

If you are having a problem, please state what it is.