Thinkpads Forum

I've ordered a T420 (i7, 4gb, 500gb, 9 cell, basically 'loaded') and am looking to pick up a few things for it.

One being a spare power adapter. I see there's a 65w with USB adapter available (57Y4600) . That'd be a handy way to avoid lugging along a USB hub (and it's own wall adapter). But I'm wondering whether or not it will have enough power for the T420. From the picture it also looks like the cord from the brick to the machine is going to be pretty short. I prefer not having the brick on the floor, so that might be a problem.

Then there's the question of how much wattage the hub ports provide, 500mA, 1A or what? Seeing as how some newer devices (tablets mainly) expect to be able to pull 1A from a charger that could be an issue too. If I have to lug along a 1A wall charger that'd eliminate one need for an integrate port. There's still a need for a USB hub on the road; usually for an external drive. But that can be powered from the laptop itself. Most other stuff can run off an unpowered hub (and they're tiny).

When building T420s the lenovo website varies on which adapter it includes. Sometimes it's a 65W, while other times it's a 90W. Dunno why, it didn't seem to be strictly related to any options built into it. Odd.

So what do I lose by using it instead of a 90W adapter? Slower battery charging while using the machine? Or something worse?

This leads to the Ultraslim 90W adapter (41R4493). I've had great luck using an iGo brick that had a similar Y-cable setup (for a whole other laptop). The same issues/questions apply. Short cable, how much wattage for USB devices?

Or should I just go with a 3rd party like iGo?

The 65 is what comes with, and will be enough for a model with integrated graphics. the 90 is for ones with Nvidia to account for the 15W tdp of the gpu.


Both will charge either when off just fine.
Both will run either when not charging.
but to charge and run a dedicated gpu model you need the 90 to avoid over straining the 65 watt ones.

That said, i use a targus 90w slim charger that has a lenovo barrel and a split off for a usb plug.
Only paid 20-30 for it on overstock.com

blackomegax wrote:but to charge and run a dedicated gpu model you need the 90 to avoid over straining the 65 watt ones.

Ah, that would explain it. The one I put together included the nvidia gpu (or that and all the other add-ons too).

I've used Targus and Kensington supplies in the past. So I'll revisit their current offerings to find something that works.

wkearney99 wrote:... One being a spare power adapter. I see there's a 65w with USB adapter available (57Y4600) . That'd be a handy way to avoid lugging along a USB hub (and it's own wall adapter). But I'm wondering whether or not it will have enough power for the T420. From the picture it also looks like the cord from the brick to the machine is going to be pretty short. I prefer not having the brick on the floor, so that might be a problem.

Then there's the question of how much wattage the hub ports provide, 500mA, 1A or what? Seeing as how some newer devices (tablets mainly) expect to be able to pull 1A from a charger that could be an issue too.

Here's an overview of the 65W AC Adapter with USB hub:
http://www-307.ibm.com/pc/support/site. ... MIGR-76128
It's said to be compatible with all T420 models. Three ports are powered, whatever they mean by that. The fourth port is for charging only, and isn't data capable.

TTY wrote:Here's an overview of the 65W AC Adapter with USB hub:
http://www-307.ibm.com/pc/support/site. ... MIGR-76128
It's said to be compatible with all T420 models. Three ports are powered, whatever they mean by that. The fourth port is for charging only, and isn't data capable.

Ah, thanks for that. It doesn't mention the wattage it offers via those ports. Is that saying only 3 of the ports can do data, or is it say that all 4 can do data, but only one can do charging to 'specialized' devices? Having a dead data port seems like it'd cause a lot of stupid support questions. More than having a higher-power port would incur.

Still, it looks like a 3rd party setup might be a better solution anyway. Having to keep the power brick that close to the laptop would be a hassle for how I typically use the machines.

wkearney99 wrote:... It doesn't mention the wattage it offers via those ports. Is that saying only 3 of the ports can do data, or is it say that all 4 can do data, but only one can do charging to 'specialized' devices?

Only three ports can do data, the fourth one is merely for charging. The data capable ports are said to offer standard charging capability, which would mean a minimum of 0.5 A on each port.

Is there a 90W version with USB ports? If so, what is the PN/FRU #?
Is there a 20V version for X6x and R6x TPs and a 16v version for T4x and X3x TPs?
Thanks