PowerBook G4 PRAM battery

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Level 9

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PowerBook G4 PRAM battery

A friend donated his retired 17" 1Ghz PowerBook G4 to my collection of older Macs. It worked when he took it out of service but it's been stored off power for several months. Does the PowerBook PRAM battery recharge like the ones in the original G3 Powerbooks or does it run down and die like the 3.6V 1/2AA PRAM batteries in desktop Macs? I've noticed they are quite expensive and not the easiest item to replace.

I can't do any testing at the moment because he forgot to send the power adaptor and the main battery is DOA. Fortunately, he will post the adaptor tomorrow.

Thanks in advance,

Allan

PowerMac G4 MDD 1.25G SP 1G RAM;, Mac OS X (10.4.11), ; MacBook Pro C2D 2.2G 15" (10.5.1); PowerBook G4 1Ghz 17"

Posted on Apr 8, 2008 10:45 PM

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Answer 1

Best reply

BGreg

Level 6

17,552 points

Apr 9, 2008 4:26 AM in response to Allan Jones

The internal battery is like a large lithium watch battery, and to my knowledge does not recharge, it just runs out at some point. Runs around $90 for replacement part.

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Answer 2

Allan Jones Author

Level 9

68,714 points

Apr 9, 2008 12:33 PM in response to BGreg

Thanks, BGreg.

This is my fist PowerBook. Other than not keeping date and time, are there any specific problems associated with a dead PRAM battery in this model. I know it can wreak havoc in a Beige G3 and some of the pre-G3 models. I've replaced PRAM batteries in Wallstreets before and that helps with several problems, but the Wallstreet is Old World ROM.

If I have a good main battery, have the computer plugged into wall power most of the time and is connected to our always-on home network, can I except reasonably normal function should the PRAM battery be truly shot?

AJ

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Answer 3

BGreg

Level 6

17,552 points

Apr 9, 2008 8:11 PM in response to Allan Jones

The only other function is if the system is sleeping and the power goes, and the main battery happens to go, a dead internal battery would cause the system to go dead. However, if the main battery is good, and it's plugged in as you described, you shouldn't see any difficulty in operations.

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Answer 4

Allan Jones Author

Level 9

68,714 points

Apr 9, 2008 9:03 PM in response to BGreg

Thanks!

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Answer 5

Jul 2, 2008 3:51 AM in response to BGreg

I wonder... 90¢ is quite steep, and why should one buy a new board, just to replace the battery. Even a large lithium battery costs only a fraction of that.
Does anyone know the type of battery used in the 922-6007 PRAM battery board assembly?

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Answer 6

Allan Jones Author

Level 9

68,714 points

Jul 2, 2008 8:42 AM in response to hginnow_max

I've done a lot of research since April and I have never seen that battery offered separate from the little USB sub-board.

However, here's the good news: after finally getting the power adaptor from my friend, I left the old PB17 plugged in for a couple of weeks and now the back-up battery works! Must be rechargeable.

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Answer 7

Jul 22, 2008 10:22 AM in response to Allan Jones

I've just changed the USB / PRAM Sub-Board for my friend, at the same time changing the main battery for a new one (original being almost 5 years old!).. however my friend broke his 17" power adaptor, question is will a 12" or 15" replacement adaptor work for charging? If not will it work just for by-passing the battery when at home etc..? There's so many cheap 12 & 15" chargers on eBay but very few 17" ones.

Cheers

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Answer 8

Allan Jones Author

Level 9

68,714 points

Jul 22, 2008 3:39 PM in response to Terra Incognita

Hi,

When my friend sent the power adaptor, it turned out to be a 45W from a 15" PBook, not the 65W for the 17". It seems to charge and run the computer, but this Mac is lightly used and is on AC power all the time due to a flaky main battery (87 health/107 cycles but dies between 60 and 70 percent).

Yes, a smaller PS will work, and may work well. I think it's a decent short-term solution. See how the charging and running work out.

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