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dan85
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Posts: 24
Registered: ‎08-17-2012
Location: California
Views: 13,622
Message 1 of 10

T440p Using Lower Wattage AC Adapter

I recently got a T440p. The laptop came with a 135W adapter.

 

I would like to order an additional adapter.

 

When I search for compatible adapters on Lenovo's site by entering my model number, it lists 65W, 90W, 135W, and 170W adapters.

 

http://shop.lenovo.com/SEUILibrary/controller/e/web/LenovoPortal/en_US/catalog.workflow:find-compati...

 

What would be the consequence of using an adapter lower than 135W (which the laptop came with)? Slower charges? Reduced CPU speed? I imagine the lower wattage adapters would work since Lenovo lists them in the store when I searched for my machine.

 

The machine has a quad core CPU and a discreet graphics card.

 

Thanks.

Guru
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Message 2 of 10

Re: T440p Using Lower Wattage AC Adapter

Hello.

 

You can run your machine on lighter to normal operations on a 90W adapter, and the CPU should operate normally in a majority of situations. However, if the discrete graphics are being used as well, it will reduce the functionality / slow down the charging of your machine, and that is certainly not an optimal situation for a powerful laptop such as you've got.

 

You need a 135W adapter to run it at full capacity. Period. I got a spruced up T440p myself as well as a 170W W520, and I would never cut corners when choosing an adapter for them.

ThinkStation P500 - Xeon E5-1650v3/32GB // ThinkPad P70 - Xeon E3-1505M/32GB
ThinkPad W540 (20BG) - i7-4800MQ/32GB // ThinkPad W520 (4282-W4Q) - i7-2720QM/32GB
ThinkPad T450s (20BW) - i7-5600U/12GB // Yoga 900 - i7-6500U/8GB
ThinkPad T61 (7665-CTO) - T7700/4GB // ThinkPad T60p (8741-C2G) - T7400/4GB
dan85
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Message 3 of 10

Re: T440p Using Lower Wattage AC Adapter

AtliJarl, thanks for the quick reply.

 

> " I would never cut corners when choosing an adapter for them."

 

The most appealing aspect to me of the less powerful adapters are their reduced size. I thought I could order a less powerful adapter to keep in my backpack as opposed to the 135W, which is larger.

 

I don't travel with the laptop often, but when I do I will be using it at full capacity, so I will take your advice and use a 135W.

 

 

Guru
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Message 4 of 10

Re: T440p Using Lower Wattage AC Adapter

Yes, that was an issue too for me when I bought my W520, usually I have it docked, but when I take it with me, hefty as it is by itself, the 170W adapter sure doesn't help. The T440p with the new 135W is a kitten in comparison.

 

But as I said, if you do the "heavy lifting" on it at home and don't require it to run at max power when on the road, the 90W will do its job just fine, and in no way will it result in any damage to your machine. A client of mine has an i7 T520 with discrete graphics that uses the 135W, but as he doesn't require it at full power on the road, he has a 90W in his computer bag for that. Zero problems.

ThinkStation P500 - Xeon E5-1650v3/32GB // ThinkPad P70 - Xeon E3-1505M/32GB
ThinkPad W540 (20BG) - i7-4800MQ/32GB // ThinkPad W520 (4282-W4Q) - i7-2720QM/32GB
ThinkPad T450s (20BW) - i7-5600U/12GB // Yoga 900 - i7-6500U/8GB
ThinkPad T61 (7665-CTO) - T7700/4GB // ThinkPad T60p (8741-C2G) - T7400/4GB
dan85
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Location: California
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Message 5 of 10

Re: T440p Using Lower Wattage AC Adapter

I have a lighter, slimmer laptop that I use on the road when I don't have any heavy lifting, so if I bring this new machine on the road, it will be for heavy lifting (programming, photo editing, training machine learning models, running virtual machines, etc.), so I'll bring a 135W with me in those cases. Thanks again.

 

Guru
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Message 6 of 10

Re: T440p Using Lower Wattage AC Adapter

Exactly what I do myself, I don't take the heavy lifters with me unless I really have to.

 

My pleasure in assisting.

ThinkStation P500 - Xeon E5-1650v3/32GB // ThinkPad P70 - Xeon E3-1505M/32GB
ThinkPad W540 (20BG) - i7-4800MQ/32GB // ThinkPad W520 (4282-W4Q) - i7-2720QM/32GB
ThinkPad T450s (20BW) - i7-5600U/12GB // Yoga 900 - i7-6500U/8GB
ThinkPad T61 (7665-CTO) - T7700/4GB // ThinkPad T60p (8741-C2G) - T7400/4GB
markcp66
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Registered: ‎08-05-2014
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Message 7 of 10

Re: T440p Using Lower Wattage AC Adapter

Hi,

This is a useful thread!  

What about the 65W adapter?  I just got one ordered for me, but it doesn't seem to even charge the battery and under power settings, the recommendation is airplane mode.  

Is this listed adapter (65W) even an option?  

And can you give this neophyte an idea of how the machine (T440p) will behave with that sort of power supply?  

I am guessing the recommendation is to bag the 65w and go with 135w (as I too usually are doing computational work)....is that a fair assessment?


@AtliJarl wrote:

Exactly what I do myself, I don't take the heavy lifters with me unless I really have to.

 

My pleasure in assisting.


 

Thanks!

 

Guru
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Message 8 of 10

Re: T440p Using Lower Wattage AC Adapter

A 65W adapter is cutting it really close on the T440p.

W520: 2960XM, Q2000M @ 1091/1380, 32GB RAM, 500GB&750GB HDD & 500GB SSD, FHD&MB168B+
X61T: L7500, 4GB RAM, 500GB HDD, XGA screen, Ultrabase
W550s: 5600U, K620M at 1164/1281, 16GB RAM, 512GB SSD, 3K touchscreen
X200s: SL9400, 6GB RAM, 64GB SD card, WXGA+ screen
TPT1: 1839-23U
SeniorGuru
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Message 9 of 10

Re: T440p Using Lower Wattage AC Adapter


@markcp66 wrote:

 

What about the 65W adapter?  I just got one ordered for me, but it doesn't seem to even charge the battery and under power settings, the recommendation is airplane mode.  

Is this listed adapter (65W) even an option?  

 


It depnds. Some T440p models will work with the 65W adapter and others require at least the 90W adapter. A good way to determine the minumum wattage is to consult the listing for your specific machine type and model in Product Specifications Reference (PSREF).

 

There is no harm in using a higher wattage adapter apart from having to carry a larger, heavier adapter when travelling. The higher wattage does recharge the battery faster so it's worth considering to power a dock or for permanent desktop usage.

 

Using an adapter that has a lower rating than listed in PSREF may not work, may work erratically when you use too many higher-current components or it may result in your system running at lower speeds. Don't do it.

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lisapeter
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Registered: ‎04-02-2015
Location: new jersey
Views: 12,331
Message 10 of 10

Re: T440p Using Lower Wattage AC Adapter

Understanding Voltage and Current.

An analogy with water in pipes is often helpful in understanding the basics of electricity.

Voltage is like water pressure. It is a force. If the force is too strong your pipes will burst. Too low and your shower may not work at all.

Current is like flow-rate. Litres per second or how fast your bath fills. It depends on how big your supply pipes are. If your water supply has a low flow rate, you won't be able to fill your swimming pool in 10 minutes. If your water supply can fill your pool in 10 minutes, you can still use it to connect a drip-watering system for your pot-plants that only draws a cupfull a day of water.


If the laptop need to draw 135W, your should use a power supply that is capable of providing At least that number of Whr. More is ok. Less means the device will probably not operate correctly.
you can search on google,there list the correct adapter for your laptop,such as:
http://www.laptopadaptershop.com.au/lenovo-thinkpad-t440p-adapter.html
it is a 135W adapter for your laptop
you need buy the correct adapter

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