Kensington 120W Auto/Air Adapter + NP8130 Findings...

As I said previously in a separate post... this adapter will power the system:

• It will survive a furmark test without blowing up.
• It will let you play games, I don't notice the screen dimming/brightening repeatedly (which would be a sign of the system flipping back and forth from AC to battery)...
• It doesn't get too hot while doing such, and doesn't seem to break a sweat with normal desktop use...

But, I recently had the thought experiment to see what the adapters do with NO battery, while gaming.

The NP8130 stock adapter can play anything, without the battery in the system (as you'd expect).

The Kensington 120W I have noticed, emits a high-pitched squealing noise when you start a game (must really be working it) and if you remove the laptop's battery, the computer turns off...


Now, to me, this is a sign that the power adapter CANNOT handle the required load the system is calling for... and probably means there is some pull on the battery too... or even worse yet, could have the system into a state of constant transitioning... where it's going back and forth from AC to Battery... but I just can't see it, since it's happening so fast.

Anyone have any knowledge or say on the matter? I think I've hypothesized all I can for now

 

If it's making that noise and only works when the battery is in there, I would suspect that the amperage is incorrect. The Wattage may be correct, but these Sager machines have a higher Amps draw than most typical laptops.

 

The easy way to test if the adapter can handle the full power requirements of the laptop would be to keep the battery in, boot up something that will max. out CPU and GPU usage, and sit it for a few hours.

The smarter way would be to figure out the power requirements of the power adapter, as well as the required voltage. It's almost certainly going to be more than 120 watts of power (voltage times amperage equals wattage), which likely means that the adapter is underpowered.

Can you start the system up sans battery and using the normal adapter? What about the universal? Does it refuse to boot up, or will it POST but not load Windows? Crash loading Windows? Something else?

Either way, you're likely much better off buying a (far more costly) replacement/additional power adapter directly from your reseller, as universal power adapters really don't get high enough in the wattage department for most decent laptops nowadays.

 

I realize I should have elaborated some more. There are a few other things I knew, and assumed you all did too


The factory adapter says 6.3A, 120W, 19V:
VA = 119.7W

The Kensington adapter says 0-6.5A, 120W, is capable of 19V max:
VA = 123.5W


And yes, everything works. It even works and plays games without slowing them down while playing. It's just odd to me that I can't do it without the battery being in, as I can with the factory adapter. (EDIT: But it will boot, browse web, etc. with Battery out).

See, I've done all the math, and everything looks good-- but my new test without battery I came up with, has me questioning the laptop safety...

 

It sounds like it may have peak power of 120w. The stock adapter tends to peak a bit higher from the wall to give constant output of 120w. The difference between the peak and constant is what seems to be happening. The stock adapter has no problems supplying even the max power needed while the non-stock just can't go any higher.

 

Not a problem, as I was tempted to look up the power requirements for the device before I was derailed by a client who required my assistance.

Given these numbers, it makes perfect sense that, yes, it should be functional.

Have you tried using the factory adapter, with the battery removed, and doing a test of the same event(s) that will cause the computer to power itself off with the universal adapter without the battery?

It could very well be that the unit is pulling more power than it can possibly supply. The factor adapter may be, as suggested above, underrated and thus able to keep the unit supplied. If, though, BOTH adapters crash the system without the battery, then it's an issue greater than the universal power adapter's ability to supply peak power.

Personally, I would be questioning the safety of running the power adapter at greater than 120 watts (which, assuming it is rated perfectly, is when it cuts itself off [test this by inducing a system shutoff failure state {no battery, universal adapter, full load, etc} and see if the power light on the device goes off when the system shuts off, the buzzing/humming/vibration stops, etc] and thus has almost no chance of doing anything directly damaging) which it may very well not be able to do.

The laptop will likely not suffer any damage from the prolonged usage of this device, as if it's functioning as we're assuming, it's merely being shut down improperly (which means lost data from not saving before the shutdown, possibly some operating system corruption, and general user annoyance). I, though, would not consider such a state as "optimal", and only consider it bordering on the fence between "functional" and "unacceptable".

 

Yeah the factory adapter is fine with the battery out the whole time. I think it must be that it just is capable of more than it lets on by the simple numbers on the side of the unit. (As Malibal is suggesting).

A shame though that this is probably another example of thinking you can trust hard numbers, where in fact, there's something that doesn't meet the eye.

Kinda like how meaningless "watts" has become with car stereo, amps, etc.

Anyway, what do I expect though, this factory one weighs three times as much.
(You can see why I want to use the Kensington, eh? )


I'll just keep using it then (with battery in of course) and report back if I see anything I don't like occurring. I mainly wanted to report in here, since I'd mentioned on another thread I was using it with success.

 

Here's the most concise way to ask what I was really asking in the first post:

• I've proven that the Kensington adapter needs the battery in order to run the computer while playing a demanding game.
• I've proven that the manufacturer one doesn't.

Thus, I'm afraid something like in this picture may be happening, thousands of times per second... and am wondering IF it could be damaging to have it cycling:

 

Just to wrap up... and sorry the updates are so slow, but my extended time to actually play games is rather limited... But I no longer recommend this as a power supply for the system.


I have seen once now, where the system while under load & gaming for a while (even with battery in, and battery still had charge) will just turn off randomly while using the Kensington PSU.


Hence, in conclusion, if you try to get ANY foreign adapter than the one straight from Sager, use my test I created to ensure the adapter is sufficient for your system:

• Remove your battery
• Plug in your new adapter
• Start up a light game/app
• Start up a demanding game/app
• See if the computer stays on

It should be noted that it could take a while to potentially get the system to turn off, it could be right away. Also, to be noted, FurMark did run without powering the system off in the above test state. Try your games & apps you intend to run to be safe!

If the system remains on, you know it is safe to use the power adapter. If it turns off, the adapter isn't capable of supplying the needed current, whose consequences I do not know. Leaving the battery in will disguise the problem to some degree, but, as I found, I don't recommend this practice either.

Post here if you find a different adapter that works with either machine, would be good to know if they exist!