Laptop power adapter output compatibility

I've lost my original power adapter, and I can't find the proper one in any of the stores currently available.

I've HP Compaq 6730b, and as per cutratebatteries.com it outputs 18.5V 3.5A. However, I've found an older power adapter I have which outputs 19.5V 4.62 A.

So, my question is: how much of a difference between those two it really is, and more importantly, how much of a risk would it be if I tried the power adapter I already have.

P.S. I know pretty much nothing about electricity/electronics.

Solution 1:

You should always try to find a power adapter that matches the factory specifications.

Having said that, the charger you found should be acceptable. Voltage is the key variable. Your laptop takes 18.5V and the new charger is 19.5V. That is just a just a hair under 5% difference (18.5 + 5% = 19.425). Generally speaking, a 5% variance in voltage up or down is acceptable when in computer power supplies. Plugging in an adapter with more than a 5% voltage difference and you are running the risk of damaging or destroying the laptop. As for amps, the computer will only draw as many amps as needed. Since the replacement supply offers more amps than the previous one, you are OK in that regard. If the amperage was lower, your laptop could not function correctly, or even turn off suddenly under heavy load, due to a lack of power.

Also, be sure that the barrel plug is the correct size. There are barrel plug adapters that can change one size to another. However, I dont recommend these, as they are easily lost and the added length can make it easier to damage the female plug inside the laptop when under torque. Additionally, make sure the polarity matches. There should be a diagram on the laptop and the charger that indicates if the center post is positive or negative polarity. Similar the image below:

Make sure the new charger matches the polarity. If it does, you are good to go. If it does not match, you will have to find another charger, or if you are confident with soldering electronics, you could modify the incorrect polarity of the power adapter's barrel plug.