Specifications of power bank for a laptop

I'm not sure about how it suits the forum of electronics here on stackexchange, but I hope I'm at the right place. if not, please forgive and explain.

So the case is that I own a high-end laptop (actually was a high end laptop about 3 years ago). Now the problem is that the battery got broken, and I can't repair or change it because the warranty is valid and the production of these batteries was stopped.

So I was wondering if can I get a large powerbank (like those for jump starting a car) that will provide me the charging capability everywhere I need - kind of a "battery replacement"?

from the specifications of the computer charger, I need a power of 19V and 6.5A. but I decided to measure the real current the computer uses and what I've got is that it's actually taking 99% of the time between 2 and 3 Ampers. (and rarely jumps to 4 for a short moment)

Will it work if I get a powerbank of 30Ah capacity and 3A 19V capabilities? will it be reliable and is it reasonable that such a powerbank would provide 900+ charging cycles?

I would appreciate a lot your help,

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  @BigChris thanks for your comment, the computer is Asus n53sv. I tried to search ebay and amazon but without too much of success. all the batteries I found werent good (by reviews). what do you recommend? 

  – Ami

   CommentedJun 30, 2016 at 17:38 
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  Can you upload a picture of the battery (with any codes/model numbers in view)? P.s. a simple search finds loads of possible places that offer replacement batteries (whether they're original manufacturer parts is a different matter)... but the device, to most, is out of warranty and old so it's worth a try. 

  – Kinnectus

   CommentedJun 30, 2016 at 17:39 
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  @BigChris this is all the info I could find imgur.com/a/2hzoe p.s yeah I know, that's what I thought at the beginning, to get a replacement battery. but after I saw the negative reviews on most of the batteries I found I decided to think to this direction of getting a powerbank. what do you think? 

  – Ami

   CommentedJun 30, 2016 at 17:51

  
  

  I'd just get a replacement battery since that's basically what you're doing - just creating an external battery. They can't void your warranty per the Magnuson-Moss Warranty Act

  Warrantors cannot require that only branded parts be used with the product in order to retain the warranty. This is commonly referred to as the "tie-in sales" provisions, and is frequently mentioned in the context of third-party computer parts, such as memory and hard drives.

  Unless they can prove something under warranty was damaged as a direct result of you changing the battery, legally you're still protected. Getting that through their customer support is a completely different matter and may have to involve lawyers.