65W vs 90W

[alofano]

As you may have figured by now that I am green, to say the least. I have noticed that some T60's come with 65W and others come with 90W. Besides the fact that 90W is more powerful than the 60W, what is the major difference ? Does that mean that with the 90W you can add more accessoiries like printers, scanners, ext. units ? Again, excess my ignorance. Thank you forum members.

[Harryc]

The 90W mainly was shipped with models that had a discrete GPU due to the additional power demands of it. It is also recommended for docked use. So in a way yes, it provides more power for more devices.

[dr_st]

Harryc is spot on.

Integrated graphics models shipped with 65W, discrete models shipped with 90W.

While Lenovo does not recommend using the 65W for discrete GPU, I've done it a number of times (with ATI X1400), and it works just fine.

With average power draw being under 20W, I find it unlikely that even if CPU/GPU/HD are both at max, and a number of external USB devices are used at the same time, the power draw can exceed 65W on these machines.

Not sure about the FireGL models, though.

And I would never run the dock off 65W. I'm not even sure it will work fully.

[AIX]

65W versus 90W AC power adapters

[zern]

I have a T60p with discrete graphics - the ATI FireGL - as well as a second HDD in the ultrabay. I travel with the light 65W power brick and run the machine off it with no issues.

The 65W does get a little hotter than the 90W. And the battery takes a bit longer to charge. Other than that, no issues.

[Radioguy]

The earlier thread AIX linked covers this, but it bears repeating: hotter is bad. It's aways best to get a 90W if you can afford it.

Harryc is spot on.

Integrated graphics models shipped with 65W, discrete models shipped with 90W.

It shipped with docks too.

With average power draw being under 20W, I find it unlikely that even if CPU/GPU/HD are both at max, and a number of external USB devices are used at the same time, the power draw can exceed 65W on these machines.

If all the devices are bus powered external drives, say more than three, plus one in the ultrabay, and you're using bluetooth, wi-fi and chrarging a battery...well, I wouldn't even think of a 65W in that situation (and I've been there).

And I would never run the dock off 65W. I'm not even sure it will work fully.

It won't, and that's with integrated graphics too.

[dr_st]

If all the devices are bus powered external drives, say more than three, plus one in the ultrabay, and you're using bluetooth, wi-fi and chrarging a battery...well, I wouldn't even think of a 65W in that situation (and I've been there).

But at that point, integrated versus discrete GPU probably won't make any difference anyways (and you're on integrated, so you probably think alike).

Won't the USB total power output limit be reached before you max out the 65W adapter though?

[jdrou]

Won't the USB total power output limit be reached before you max out the 65W adapter though?

I'd think so; the USB standard only requires a port to provide 2.5W (500mA at 5V) and Thinkpad ports probably provide around double that (2.5" hard drives generally need about 1A to spin up and I usually don't need a 2nd port to power one). Most likely the 65W adapter can handle any load on an Intel graphics Thinkpad although the battery might not charge much if at all. On my descrete-graphics Dell laptops using a 65W-70W adapter automatically puts it in low-power mode as if it was running off the battery (the primary adapter on my Precision M4400 is 130W and the recent 17" Precisions come with 210W adapters).

[alofano]

My T60 came with P/S PN 92P1160 65W 20V 3.25A.

Does anyone have the PN of the 90W ?
I know it is a 90W 20V but how many amps ?

Thanks a whole bunch.

Edited : amps not watts, so sorry.

[Harryc]

Does anyone have the PN of the 90W ?
I know it is a 90W 20V but how many watts ?

There are several FRU's for the 90W adapter, .e.g. 40Y7659
The 90W adapter would be 90 watts. The 65W is 65 watts.

[Radioguy]

I'd think so; the USB standard only requires a port to provide 2.5W (500mA at 5V) and Thinkpad ports probably provide around double that (2.5" hard drives generally need about 1A to spin up and I usually don't need a 2nd port to power one). Most likely the 65W adapter can handle any load on an Intel graphics Thinkpad although the battery might not charge much if at all. On my descrete-graphics Dell laptops using a 65W-70W adapter automatically puts it in low-power mode as if it was running off the battery (the primary adapter on my Precision M4400 is 130W and the recent 17" Precisions come with 210W adapters).

Well, I can speak from experience that in circumstances approaching my previous "worst case scenario", the 65W brick became sizzling hot. Those incidents are documented in the other thread. As for idle drives, it may fly, but in a continuous torrential read/write situation, the load is just too much for me to consider a 65W one. There's a difference between a 65W brick handling that for a few minutes, and doing so for a few hours.

I still have my 65W, though. I would just add my 4A powered external hub if I had to use it. Hey, I can do 7-8 externals with that and a 90W.

[rkawakami]

I know it is a 90W 20V but how many amps ?

Formula is: Power (watts) = Voltage (V) x Current (amps)
Therefore: Amps = Watts/Voltage so for your question, 90W = 4.5A (at 20V)

[virge]

And I would never run the dock off 65W. I'm not even sure it will work fully.

I've done it and did not have any problems. This was with my T60 w/ ATI graphics, USB keyboard and USB wireless mouse. I did not check to see how hot the adapter was getting, but I didn't have any problems at all. I eventually did move up to a 90W adapter though when I added more devices. E.g. USB powered external HDD, webcam, and started using ActiveSync with my phone. I using every USB port on the dock at the moment.

I notice that the Power Manager software can detect whether you're using a 65W vs 90W adapter. Maybe it downgrades performance to compensate? I wouldn't have noticed with the applications I was using.

[alofano]

WOW, Thanks Ray.

The last time I used that formula was in 1974-75. Boy I am really good at looking bad. Thanks again for the memories.

[alofano]

The AC ADAPTER'S come in two parts, The p/s or brick and the a/c cord or power cord ( I always thought that this was one unit but I was wrong).

I compared my p/s and a/c cord with my friends who has the same ThinkPad T60 but different type. Now my P/S (brick) is the same as my friends BUT the a/c cord's are different specs.

A/C Cord 1 :
# on the paper around the cord is : 39M5016
stamped on the plug 7A 125V
ECH19160M
Longwell
26/06

A/C Cord 2 :
# on the paper around the cord is : 39M5016
stamped on the plug 3A 125V
ECH19160L
Volex
50/06

Same specs on the brick but different specs on the Power Cord. Which one is better to have the 3A or the 7A ? I'm confused are you ?

Thanks guys.

[AIX]

Both of them are good enough for you. They can support up to:

7A * 125V = 875W
3A * 125V = 375W

[jdrou]

Both of them are good enough for you. They can support up to:

7A * 125V = 875W
3A * 125V = 375W

I don't think that relation holds exactly for AC as it does for DC but yes either one should be fine for a 90W adapter.

[AIX]

@jdrou - Yes, you're right, EE is not my field; here is the correct formula for AC, I think.