Spare laptop power adapter input amps differ from OEM. Does it matter?
2014-06
R_G
I purchased a spare power adapter for my ASUS Q500A laptop. When I received it, I checked the specs and found that they differ than the OEM adapter. The OEM input is 100-240V 50-60Hz 2.0A. The spare input is 100-240V 50-60Hz 1.2A. Both outputs are listed at 19V 3.42A. Does this difference matter? Should I use the adapter or return it? Thanks...
horta
Your original OEM adapter had a poor power factor. 2.0Amps * 100V is 200 VA of apparent power. Apparent power is the maximum amount of real and imaginary power. Real power is delivered to and absorbed by the power adapter. Imaginary power (or reactive power) is power that must be drawn in by the power supply by capacitors or inductors and then sent back to the grid.
Usually laptops take either 85 watts or 65 watts. The output of both of those adapters says they are 65 watt adapters. I don't see any issue at all with the after market adapter. If anything it has better power factor.
Power factor is the ratio between real power and apparent power. Ideally, your PS should have a PF of 1. In your case, the OEM adapter looks to have a PF of 65/200=0.325 (ignoring losses). Your after market PS has a PF of 65/120=0.54. One reason PF is important is due to the extra losses incurred by the extra current necessary to drive poor PF devices.
Lastly, if somehow the aftermarket one isn't able to produce 65 watts, the only downfall you'll have with the aftermarket adapter is that your battery may charge slightly slower.
Infadel
It sounds like the power adapter you bought will work fine. The output voltage and current capacity are what's important, as that's what your laptop will see.
If you want to be extra sure, you can also check the polarity on the barrel plug. Just take a voltmeter and make sure the voltage on the old plug is the same polarity as this new one. It's almost certain that it will be the same, but it doesn't hurt to check.
CT.
I'm looking to buy a number of car power adapters to be used with some Dell laptops.
http://www.cdw.com/shop/products/default.aspx?EDC=1382005
^ This is the item I am currently looking at.
Will it be able to power a Dell Lattitude E6500?
Looking at the power supply of the laptop, it states that it is a 90W-AC Adapter. The car adapter states that it is a 60W DC - AC Power Inverter.
Will this work? Do I need an DC-AC Power Inverter that is 90W or higher? I am nothing close to an electrician, please help me out.
Thank you.
Ignacio Vazquez-Abrams
If your laptop is always in low-power mode then the 60W inverter may be enough for it. If you want to be certain that you don't burn the inverter out then you should get at least a 126 (90*1.4) watt inverter.
Blackbeagle
If you run a 90 watt laptop on a 60 watt power supply you risk overdrawing the power supply (early death for the charger) and also some chargers may run the laptop, but the battery won't charge. Targus and Kensington usually note that while their 60 watt chargers may spin up a laptop, they won't charge the battery for example.
rob
Ideally, you would get a DC power adapter for your laptop, rather than converting from DC to AC, then back to DC again. But if you want to be able to plug in other devices, you should get an inverter that can handle at least 90W.
You could get the 60W adapter and try it, but you should first measure the AC adapter's draw under varying loads while plugged into the wall--for example, maxing out the screen's brightness and ripping a CD or DVD while the laptop is fully charged, vs. doing the same while the laptop is charging.
If you do end up getting the 60W inverter and you happen to overload it, the fuse in the inverter should blow. If the battery is already charged when you hook up the laptop, you might be fine. But if the battery is partly depleted and the AC adapter tries to charge it, you'll probably end up drawing more than 60W. A slightly annoying workaround would be to physically remove the battery when using the laptop in your car.