AC Adaptor Help: 90w vs 120w

[VLV]

Hi,
I'm buying my first laptop from PCSpecialist, with:

i7-3632QM
NVidia Geforce GT 650M
7200 rpm HDD
...and the battery says "62.16WH"

but I don't know which power adaptor to select: the 90w, or the 120w ?
What are the practical differences, advantages and disadvantages ? (If any)
....so, which one would be a better choice ?

VLV

 

[ChrisByatt]

More watts = faster charging. Depends if you're going to keep it plugged in a lot. If it's gonna be plugged in a lot go for 90w

 

[ubuysa]

Watts is a measure of electrical power so more Watts means more power, that means more charging current at a given voltage. More charging current means your laptop battery charges faster (though there is a limit to how fast a battery can accept charge) but it also means more heat given off by the charger (because some of the power is lost as heat).

So, if you have a completely flat battery the 120W will charge it faster than the 90W. How much faster depends on how fast the battery can accept charge.

As ChrisByatt says, if you leave the laptop plugged in then the 90W is all you'll need. If you regularly run on battery and discharge it a lot then the 120W is probably a better bet.

Also, if you have a completely flat battery, the 90W charger will probably run flat out to provide enough charging current, whereas the 120W may need to provide significantly less than it's maximum current (there is a limit to how fast the battery can accept a charge remember). So the 90W may run hotter charging a flat battery than the 120W. And because the 90W will take much longer to recharge it than the 120W you may have a hotter charger running for a longer period with the 90W. That might be an issue for you.

Of course price and the physical size of the charger is probably also an issue. So if you want your laptop to be easily transportable you might not want the added weight and size of the 120W charger to carry around.

It's really about how important it is for you to be able to recharge your battery quickly and how transportable you want it to be.

I hope that helps some?

 

[VLV]

Many thanks for the very detailed answer ,awesome
Sorry for only replying so late, I couldn't answer any sooner.

Now I only have one doubt left, which is in relation to power requirements of the components, will 90w be enough to give max performance to the machine ?

I created a new thread for this question, I'll post the link when it gets approved.

btw, how do I give +rep ?

 

[Rakk]

I created a new thread for this question, I'll post the link when it gets approved.

Given you've just asked the question here you don't need another thread for it since it is very much related , so your other thread has been deleted, if you hadn't have asked in this post I would probably have just merged it in here anyways

btw, how do I give +rep ?

Click the little star symbol on the left hand side of the footer of the post that you want to give rep for

 

[VLV]

Given you've just asked the question here you don't need another thread for it since it is very much related , so your other thread has been deleted, if you hadn't have asked in this post I would probably have just merged it in here anyways

ok, in that case I'll post the specs, it's an inferno btw

Processor (CPU)
Intel® Core™i7 Quad Core Mobile Processor i7-3632QM (2.20GHz) 6MB
Memory (RAM)
16GB KINGSTON HYPER-X GENESIS 1600MHz SODIMM DDR3 (2 x 8GB)
Graphics Card
NVIDIA® GeForce® GT 650M - 2.0GB DDR3 Video RAM - DirectX® 11
Memory - Hard Disk
750GB WD SCORPIO BLACK WD7500BPKT, SATA 3 Gb/s, 16MB CACHE (7200 rpm)
Memory Card Reader
Internal 9 in 1 Card Reader (MMC/RSMMC/SD: Mini, XC & HC/MS: Pro & Duo)
Sound Card
Intel 2 Channel High Definition Audio + MIC/Headphone Jack
Bluetooth & Wireless
GIGABIT LAN & WIRELESS INTEL® N135 802.11N (150Mbps) + BLUETOOTH
USB Options
2 x USB 3.0 PORTS + 1 x USB 2.0 PORT AS STANDARD
Operating System
Genuine Windows 8 64 Bit - inc DVD & Licence
Webcam
INTEGRATED 1.3 MEGAPIXEL WEBCAM

 

[ubuysa]

Many thanks for the very detailed answer ,awesome
Sorry for only replying so late, I couldn't answer any sooner.

Now I only have one doubt left, which is in relation to power requirements of the components, will 90w be enough to give max performance to the machine ?

I created a new thread for this question, I'll post the link when it gets approved.

btw, how do I give +rep ?

If PCS offer a 90w charger then it will be beefy enough for the laptop, whatever the spec I should think. Your only problem might be (again) if you have a completely flat battery and you want to get max performance from the laptop whilst it's charging, a 90w charger might struggle to provide much of a charge under those conditions - that's just a guess, but based on experience. I have seen (non PCS) laptops that will not boot with a completely flat battery even when on charge, because the flat battery is sucking so much power from the charger for the first hour or so that there is none left to power the laptop.

Again, if you rarely flatten the battery then the 90w charger will be ok but if you often want to recharge from a flat battery and get max performance at the same time the 120w is a better choice.