X1 Carbon ships with a 90W AC Adapter?!

[veechee]

So the X1 Carbon is 3 lbs, but they are selling it with a 90W Adapter, which from what I can find weighs in at ~0.79 lbs.  Why does an Ultrabook, which by design has a lower power CPU, need a higher watt adapter than an X230/T430/T430s?!  The 65W adapter that those can use is ~0.57 lbs and they are physically smaller too.

I just don't get a design oversight like this laptop.  Why change the power adapter connector but make the adapter itself big, heavy and not unlike most ThinkPad adapters besides the new connector.  The ASUS Ultrabook adapter is small and light so why can't the X1's?

[RedEd12 Support Specialist - Retired]

Hi there,

the unique 90w adapter for the X1 Carbon probably has something to do with the new Rapid Charge Battery that it comes with. The 90w adapter allows it to charge up to 80% in about 30 minutes so I'm postulating that a 65w adapter will not enable this feature, or may not even be able to adequately power the system to it's full capabilities. This would need to be fully verified, but from what I've read so far, seems logical.

Best regards,

Ed

 *Edit* okay, so it does look like the X1 Carbon will support a 65w adapter but will charge slower. I don't think older 65w adapter will work though because the plug is square shaped.

[Ron_9972 Support Specialist]

I agree with ED.  You can have a 65W adapter, but it will take longer to charge.  I'm not sure if the 65W supports RapidCharge.

[hausman]

FWIW on other ThinkPads like the T430s, any 90W charger, including those intended for older systems, will Rapid Charge the battery. Lenovo explicitly states that the 65W adapter will not support Rapid Charge, even if the adapter came with the T430s.

From this I conclude that support for Rapid Charge isn't built into the adapter and that the reason X1C ships with 90W is to provide enough power for Rapid Charge.

Disclaimer: This is all just educated speculation on my part, not the official answer.

[veechee]

I'm aware of the Rapid Charge feature on the other T and X-series ThinkPads.  Personally I never configure my laptops with the 90W adapter so I never use that feature, although I'm sure some people do.

The difference of course with the X1 is a lower power processor than the standard T and X-series ThinkPads, so (this is just speculation on my part) you would think that a 45W adapter could power the computer normally (I believe this is what the ASUS Ultrabook uses with the same processor and a 1920x1080 IPS display), and a 65W could then provide the extra power for Rapid Charge.

Now even if I'm wrong and the full 90W is in fact needed for Rapid Charge, then why not at least offer a 45W or 65W adapter when ordering for those that don't want that feature (as is offered now on other ThinkPads)?  It seems really silly to force a big heavy adapter on buyers spending money on the slimmest, lighest ThinkPad.  Right now I see no such accessory on the Lenovo store or listed on the Quick Pick accessories website.

I would strongly consider an X1 for one or more senior staff in our company, but the lack of Ethernet is one strike, the inferior display to ASUS (which I won't buy though since I'm trying to standardize on ThinkPads) is strike two, and most of 1 lbs worth of AC adapter is third strike.  You're outta here X1 Carbon.

[lead_org Microsoft MVP Contributor]

The X1 also come standard with the rapid charge feature and the 90 watts adapter.

During the Rapid Charge process with the laptop on doing CPU/GPU intensive work, i have measured a power draw of around 75 watts plus. The 65 watts adapter can allow the ThinkPads to draw up to 72 watts of power, but it is not nearly enough to run the laptop at full throttle and rapidly charge the battery.

I think Lenovo included the 90 watts adapter as a standard safety precaution to give enough safety margin for people whom are charging the battery + running the laptop at full throttle.

An educated guess would be that once Lenovo comes out with the power plug converter converter cable, you would be able to use the 65 watts adapter in the machine, but you would probably lose the rapid charge feature.

[veechee]

lead_org.

"During the Rapid Charge process with the laptop on doing CPU/GPU intensive work, i have measured a power draw of around 75 watts plus."

With this measurement are you referring to what other models do (e.g., X220/X230, T420/T430)?  Because the X1 has a less powerful processor than standard ThinkPads, which is why I would expect lower power requirements even for RapidCharge.  The i7-3667U has a max TDP of 17W, whereas the i7-3520M which is the top chip in an X230 or T430 has a max TDP of 35W:

• Intel® Core™ i7-3667U Processor specs
• Intel® Core™ i7-3520M Processor specs

So that's why I am surprised Lenovo needs the same capacity adapter that can run a T420 or T520 with dedicated graphics to run an Ultrabook with onboard graphics and almost no ports.

Regardless of the longer battery life newer notebooks and Ultrabooks are capable of, the reality is that most business laptop users are packing the adapter with them for travel, use at home, etc.  I find the weight of my bag on my shoulder is noticeably different when my 65W adapter is in it.  So I get offended if a system is offered with more adapter than is needed to get the job done.

[lead_org Microsoft MVP Contributor]

I measured X1 not X1 carbon, and it contained an i5-2520m CPU. You probably can measure the amount of power your thinkpad uses even without rapid charge feature. My T420 can draw around 40 watts for the charging process. Rapid charge would need even more.