Question Looking for powerpack for HP laptop

[frisket]

I have a HP Envy 17" laptop and I need a powerpack that will recharge it (preferably twice) so that I can work in a location with no mains power (new battery life is only 2hrs)

The mains charger that came with it says 90W, and the HP docs say the internal battery is rated 55Whr. Has anyone suggestions for a suitable powerpack, or warnings, etc?

Dell make powerpacks for their laptops, but (weirdly) HP don't, and although the plug tip fits, the Dell powerpacks don't charge HP kit — maybe some smarts in the connection talk to the laptop to ensure it's a Dell. The (now closed) thread at Can i use a dell laptop's powerpack to charge an hp laptop suggested the tip polarity may be different, but how do I find this out? The simple answer to the OP's question is NO.

 

[helpstar]

The powerpack and the laptop has a sign to verify the polarity. In this example plus would be inside and minus outside the tip. These signs have to be identical to match the polarity of the laptop´s jack and the powerpack´s tip.

View: https/i.stack.imgur.com/riJVR.jpg


some laptops don´t like to be undervolted, so 19.5V should be the voltage for the power pack.

Amperage can be higher than the original charger and won´t hurt parts of the laptop while voltages over 19.5V could. The amperage for your laptop should be not less than 4,62A to provide 90W. (90W divided through 19,5V equals 4,62A)

Some tips will "fit" but won´t charge because these are not connecting correctly. You will have to get the exact match of the tip to get a correct connection, or plus or most likely minus won´t have a connection to the charger port of the laptop.
tip size: 4.5*3.0mm

 

[frisket]

Thanks very much. I found the +/- symbol on the charger, so it's +ve outside. 19.5v and 90W are clearly marked (once I got a seriously powerful zoom lens) so I've ordered a 4.5mm×3mm-to-USBC adapter because all the new powerpacks assume USB-C