Looking for an External Battery for Laptop

[Corrupt_Liberty]

I have an Asus N550JK laptop. It currently gets me about 3 hours of battery life which isn't quite enough to get me through classes everyday. I'm looking for an external battery to extend my battery life another 2-3 hours. So far everything I've found is for laptops with 65 watt power supplies and mine has a 120 watt. Is there anything out there that will solve this problem? I'd rather not buy a new laptop at this time.

[Corrupt_Liberty]

1 hour ago, Name Taken said:

Chargetech 27000

 

https://youtu.be/LG-AZz_nm5E?t=563

 

Thanks for the quick reply. I'd actually prefer something that outputs 19v DC (20v?) natively so I don't have to carry my power adapter. Also that model is limited to 85w and my laptop adapter is 120w.