5 Replies Latest reply: Dec 27, 2010 9:07 PM by louie
GeneMike Level 1 (5 points)
The battery life was dwindling on the original battery in my G4 1.67 GHz 15" Aluminum. I replaced it with an after market battery touting a 25% capacity (5000 MAHz) increase. It does seem to have an increased capacity but the battery indicator has become erratic. Today, with a gradual decrease from full charge to 62%, suddenly the notice came on warning that it was running on reserve power and it showed 4% charge. I have twice let it run down to shutdown and then recharged it. The indicator still is erratic??

PB G4 15", 2 G5 2.0Ghz, Mac OS X (10.4.11), Apple for 30 years and counting!
  • louie Level 4 (2,945 points)
    My first thought is that the replacement battery is simply bad. I would be suspicious of claims of 25% increase at a low price. Have you contacted the vendor about warranty or tech support?

    Can you try the behavior on the old battery? Did you reset the PRAM? What is the battery info in System Profiler/power?
  • GeneMike Level 1 (5 points)
    I don't recall saying anything about a "low price??" The battery information looks like this:

    Battery Information:

    Battery Installed: Yes
    First low level warning: No
    Full Charge Capacity (mAh): 4688
    Remaining Capacity (mAh): 4688
    Amperage (mA): 0
    Voltage (mV): 12430
    Cycle Count: 13
  • louie Level 4 (2,945 points)
    Fair enough! Regardless of the cost, you probably just have a bad battery. Sudden drops in capacity are typical of a bad cell in the pack.

    -Try the old battery and see if it behaves erratically. If not, the computer is probably OK.
    -Reset the power management unit and PRAM, just in case the computer has be reset for the different battery:
    -Ask your battery vendor for tech advice on this issue or warranty service.
  • GeneMike Level 1 (5 points)
    The battery is a NewerTech from OWC. The tech there had suggested - first, a PMU reset and, if not resolved, an nvram reset. If that didn't do it, I should call Customer Support for an RMA.

    I did a PMU reset and it seems to have done the trick - afterward, I ran CD's on the machine (something I don't normally do!) constantly for well over 4 hours. Airport was also on and I was connected to the internet! My old Apple battery would never have gone anywhere near that long with that or any other load. The battery indicator went down gradually until it shut down at 0%.

    It's only one cycle and I will be watching it closely but looks good for now.
  • louie Level 4 (2,945 points)
    Sounds good. If you have not already done so, I suggest reviewing Apple's battery calibration notes
    and battery notes
    unless Newertech advice is different.