t41p dc adapter 56 watts

[ravenjim]

I purchased a 56w dc power adapter on ebay for my t41p. They claimed it is compatible with my laptop but the Lenovo site recommends a 72w adapter. The seller claims the lower wattage adapter will not affect the operation of my laptop and they use it on theirs all the time with no problem. What do you all think about using the 56w. [/b]

[richk]

When I used one on a T4x laptop, the battery did not charge. By the way, I was using it on a 15" screen machine with 1.5 GB memory, which might have affected things. I started the power management stuff and checked the battery information page. I had thought the MB was sick, until I realized I had used an adapter from an X31. There is a fuse on the MB that controls charging and I was almost ready to replace it until I figured out my mistake.

[rkawakami]

Never use a lower wattage supply than what is specified on the laptop's product label. I'm assuming that it has 16V 4.5A on it. That's 72 watts (16 x 4.5). You run the risk of under-powering your laptop or overstressing the AC adapter.

[jdhurst]

I never stop scratching my head at these foolish recommendations to use the wrong adapter. Use what IBM recommends. There are few better engineers than those at IBM and they DO know what they are talking about. ... JDH

[ravenjim]

I thought this was the response I'd be getting. Yes it's 16volts and 4.5amps. I'm going to try and send it back. Thanks for all the responses.

[exTPfan]

The voltage, of course, is crucial, but I doubt that the wattage is. Like, I suspect, a lot of people, I have been using a 600X, a T23, and a T42 for years with each others' power bricks (54--72 watts). And for the T60, Lenovo sells both a 90 watt power supply and a smaller lighter 65 watt power supply.

[exTPfan]

Having done some more research on this, here's what I found.
If you never use more than 56W, you are safe, and it is would be difficult to get close to 56W
(see http://www.polarpower.org/technologies/ ... index.html).
If you go over 56W, something bad may happen: power supply may overheat or, worse, its voltage may drop which may damage your computer (whether this can happen with a charged battery is unclear).
IBM recommends 72W in order to have enough power to run the computer, USB devices, port replicator, DVD, and charge the battery all simultaneously.

[awolfe63]

I've tried it and if you don't have a fully charged battery, they charger can cut in and out. It works sometimes, but can be flaky. I've stopped doing it.

[ravenjim]

I'm getting the one that IBM supports, it is the 72w unit. Thanks for the info, very interesting numbers on power usage. I just didn't want to take any chances and the laptop is still under warranty.