Dv9000 AC Adapter 65w - 90w compatibility 453198-001 453199-001

Question

I have the Pavilion dv9000 - part number: KN866UA#ABA - model: dv9815nr.  It came with a 65w AC adapter.
I came across the 90w adapter and have been told it is compatible with my laptop.  Are these AC adapters truly compatible/interchangeable?
The only issue I have found is that the 90w is for systems with dual lamp display assemblies while the 65w is for single lamp.
Can I use the 90w AC adapter on my laptop that originally came with a 65w adapter?

Answer 1

When it comes to the ac adapter there are two specifications you need to focus on:
1. Voltage (output)
2. Amperage (output)
I'll use the example of an Asus notebook I have in the shop right now.  It actually shipped with a 65W ac adapter, as it only had integrated graphics.  However, there was an alternate model that shipped with a discrete adapter (nVidia 6600go).  That model required a 90W adapter.
On both models, the AC adapters are 19V output models.  Where they differ, however, is in the maximum output amperage.
The 65W max amps out is 3.42A, and the 90W is 4.74A.
Keep in mind that WATTAGE = VOLTS * AMPS...
The other thing to understand is that the ac adapter is not always putting out 65W or 90W.  The long and short of it is that the notebook (or PC) draws a certain amount of amperage per component usage.  On desktops, it tends to be a bit more constant as notebooks now have active power management, which means they adjust their performance and power usage specs according to usage (though, desktops are starting to have active power management more and more also.)
So the bottom line is that, as long as the AC adapter is compatible with the unit, a 65W requiring notebook can use a 90W adapter, because the voltage is constant and its total amperage usage will never reach the full capability of the adapter.
YOU CANNOT USE A LOWER WATTAGE ADAPTER ON A HIGHER WATTAGE-REQUIRING NOTEBOOK, HOWEVER!!!!  If a system requires a 90W, it's most likely because its maximum amperage draw is significantly higher than what a 65W can supply.
Hope this helped!