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jwblase · Mar 28, 2006, 08:50 AM

My Powerbook G3 Pismo has the following symptoms:

It works perfectly except when charging the battery. It charges to 10%, then the system thinks the battery is full. All battery tools say that it *can* contain a full charge, but the pismo (for some reason) won't charge it to full.

It will charge it somewhat. The battery symbol has it's lightning bolt, and then stops charging at some number that changes, but always under 10%.

I have a nasty feeling it's not the battery, but the PMU unit going down instead. However, a dragnet of the 'net comes up with only one other person who has had these symptoms in their patient, and he's a good, Jobs fearing MacNN user (Go Fisherking for the help!). However, it's been a long time, and he's moved on since 2004 from a Pismo to something far more shiny.

Any way I can confirm the diagnosis of the PMU? I don't want to go out and waste the $$ I don't really have on batteries if I don't need them. Powerbooktech.com has PMU units if I need them, and I can do the install myself.

Thanks for the help!

JB

sahnapiranha · Mar 28, 2006, 12:52 PM

Have you tried charging the battery in the 'other' expansion bay?

shunt · Mar 28, 2006, 04:40 PM

When I was trying to diagnose a suspect Pismo battery, I went down to the Apple Store. The "genius" opened a drawer containing some Pismo and even Wallstreet batteries for testing.

We plugged his battery in my machine, and it started charging like a champ. Case closed...

Needless to say, I was pretty surprised they kept batteries around for such old machines, and they were very helpful...not to mention surprised at how well Tiger was running on mine.

Another option, if the battery is OEM Apple with bar-code, read this thread http://forums.macnn.com/showthread.php?t=273466

At least you'll have an idea how old your battery is....they have a finite lifespan.

good luck.

jwblase · Mar 28, 2006, 05:49 PM

Yeah... tried it in both expansion bays, same problem. I didn't think that the Apple store would have Pismo stuff! I'll go to Woodfield and try it tomorrow. (Ahhhh... the luxuries of being a teacher on Spring Break!)

JB

Litflynt912 · Mar 28, 2006, 07:05 PM

Your battery could be ancient, many years old. It probably indicates that it can be charged well past what it actually can be because of a sensor fault. My guess is that in the very near future that battery will not hold any charge, or at least nothing past a few minutes.

Also, I've been on the verge of replacing my PRAM battery several times, and even have backups but every time I think the PRAM battery is gone, it springs back to life. Go figure.

jwblase · Mar 28, 2006, 10:00 PM

Using the Battery utility (I can't remember where I downloaded it from, it says this:

Battery: battery installed, above warning level, raw LOW signal
Charger: charger connected, not charging
UPS: UPS not installed
System:
Voltage: 11.583V
Current: 0.000A
Charge: 0.052Ah of 4.118Ah (1.3%)
Capacity: 4.118Ah of 4.800Ah (85.8%)
Cycles: 11

It's the "Charger" line that confuses me. Especially since the battery reports only 11 cycles, I don't see why it wouldn't be charging, unless it's a PMU problem. Hmmmmm...

JB

Litflynt912 · Apr 5, 2006, 08:26 PM

A week later, one of my lithium batteries stopped charging properly. The other was fine. I replaced the PRAM battery and now both are fine. I recommend replacing the PRAM battery as the easiest way to see if the lithium battery afterwards reads correctly.

jwblase · Apr 5, 2006, 08:50 PM

It turns out that it was a battery issue. Went the Apple store, he used Terminal to look the battery info (ioReg) and when the result came said (and I quote), "What the ****?"

The battery had worn down from sitting around for so long, yet the microchip inside still wanted to register it as a good battery. It seems that the computer didn't know what to do with the information it was receiving, so it just would tell OS X that the battery was charged at 1%.

New battery, problem solved!

JB