This has bugged me since I got one of the last powerbooks this year. I have a couple of power adapter/power cords from my original powerbook and only one from my new one. I'm wondering if there's any real difference between the new and old adapters. That is, can I use the old ones on the new powerbook safely? The cord that connects directly to the powerbook is thinner on the old ones and the plug doesn't seem to stay in the new powerbook as well as the adapter that came with it. Considering how different the two powerbooks are, I'm a little paranoid about this so does anyone know if there's something fundamentally different between the old and new adapters?

Which model PowerBooks are we talking about? It depends on how "old" those older power adapters are.

I bought the first powerbook in June 2002 (800 MHz). The new one is just a shade under 2 months old (1.67 MHz).

Your 2002 PowerBook came with a 45w power adapter, and the new ones are 65w. So it's probably *not* a good idea to use the old one with the new system.

It may depend upon the size of your PB. I think I read that the 12"ers take a different one than the larger ones.

Thanks, Jack, that's what I was afraid of.

They're both 15" powerbooks, Donna.

The NEW powercord (65 watt) will work with the older Powerbook (45 watt) but NOT the other way around. The 12" PowerBook uses the same Powercord as the 15" and 17" models.

Speaking as an electrical engineer, it may be possible to use the lower power adapters.

In general, voltage is all that matters with a battery powered PowerBook, iBook, or MacBook. That assumes a couple things:
1. the DC voltage rating on the adapters is identical ( 24 vdc ?)
2. the connectors actually fit together
3. a battery's installed in the laptop
4. there's no DC overcurrent sensor in the adapter to stop charging

I suspect the different power ratings only affect the charging rate. Higher power ratings translate to less charging time.

I think that all that can happen when using the lower power adapter is you'll draw some power off the internal battery, and gradually decrease its charge. If you're charging the laptop in the off state, a 45W adapter will take longer to charge the battery than a 65W adapter.

I doubt the adapter would overheat, and cause a fire. Of course, I could be dead wrong, and the overdriven 45W adapter could explode like an Arnold Schwarzenegger movie with the plastique explosive that Apple put inside !

Anyway, why not buy the proper adapter for the peace of mind that a few bucks will bring? Maybe iGo has a Universal adapter by now? For PowerBooks, iBooks, and MacBooks? However, I really like the YELLOW/GREEN charging LED in the old PowerBook connectors.

Chuck- I had a 45 watt power adaptor for an older PowerBook and it used to run hot but did the job for about 9 months then it quit. When I purchased a replacement the only thing available was the 65 watt unit. The 65 watt unit ran considerably cooler and never had any more power problems. I suspect that Apple discovered that the smaller unit was not adequate but they kept quiet about it. I'm an electrical inspector so I'm a natural skeptic.

"Speaking as an electrical engineer, it may be possible to use the lower power adapters." This is true, but.....

Typical problems may include boot failure if the battery is not at peak charge and the system settings result in maximum power draw - full speed, etc. Also, the system may shut down unexpectedly when the load is consistently greater than the AC adapter can support.

This comment comes from the "been there, done that" school of left-behind adapters and low power substitutes. A 65 Watt adapter substituted for a 95 watt adapter and the situation was aggravated by a weak battery!

Again, per requirements provided by Chuck M, a higher power rated AC adapter with otherwise identical specifications will perform perfectly and loaf while doing so - see George Little's note for an example. The internal battery charging is regulated within the laptop, not within the adapter.

This message has been edited. Last edited by: James R. Cutler,