Help me find an external laptop battery that will work for the ASUS G51

I'm looking for an external battery that will add 3 to 5 hours to the ASUS G51-RX05.

The power specs listed for the laptop are:

* 6 cells: 4800 mAh,, smart Lithium-Ion battery pack
* Output: 19 V DC, 6.32 A, 120W
* Input: 100~240 V AC, 50/60 Hz universal

And I believe this is the power port on the back:



Can anyone who knows a thing or two about external batteries recommend something that meets my requirements?

I'm from Toronto so a Canadian supplier would be preferred.

Cheers.

 

This should do the trick

http://www.amazon.com/Tekkeon-MP345...1?ie=UTF8&s=electronics&qid=1251315627&sr=1-1

 

Hey thanks for the link.

That Tekkeon has a listed capacity of 50Wh. And I believe the G51 standard 6-cell battery has a capacity of about 28Wh (6 x 4800 mAh, correct??).

So then this Tekkeon battery should have about 1.75x the capacity of the regular 6-cell battery? Which would be just barely 3 hours since the standard battery only gets about 1.75 hours even when idling.

Can anyone who knows a thing or two about electronics confirm my math here?

EDIT:I think my math is way wrong... I'm looking into it now..

 

Okay, so the capacity (Wh) of a battery is calculated by mAh * Voltage /1000. So the standard 6-cell G51 battery has a capacity of 91Wh (4800mAh * 19V /1000). Since it lasts about 1.75 hours before it dies, it consumes about 52Wh per hour.

Therefore I would need an external battery that is at least 150Wh in order to extend the life of the G51 by just 3 hours. In which case the Tekkeon at 50Wh is not going to cut it unfortunately...

Can anyone double check/confirm this?

 

Ok.. I'm still confused.

If an external battery has a listed capacity of 20,000 mAh, then would it have 4x the capacity of the standard G51 battery? (20,000 / 4800 = 4.1)

Therefore a 20,000 mAh battery should last almost SEVEN hours on the G51?? That seems too high..

 

someone help clarify this for me please.. i'm so confused.

the g51 also has 6.32 A and 120W... I have no idea how these numbers factor into determining battery capacity...

 

Finally, you was buyed this battery? I'm interesting in know how works this.
In ebay, some sellers sale the item plus another battery extra for about 175$....
What you means about this?

 

Time (in hours) = (mAh/1000) * (battery voltage / device power in watts)

Note that your power adapter is rated at 120W, meaning that is the maximum power that the power adapter can support. Your G51 notebook doesn't always use the full 120W, especially when you're idling or performing non-intensive tasks. If you plug and chug the numbers, you'll see that the battery life for your 6-cell battery is less than 1 hour if you're constantly utilizing the full 120W.

 

Then, David, how many time can runs this laptop with the battery that you put?

 

While performing just basic office tasks, I'd say this external battery can add 1.5 hours of battery life.

 

Regards. Visiting the webpage, you can buy a combo, two batteries in one pack. Aproximatly 180$, and we've 3h plus....
it's a better option actually, i think.

 

If you have the same Asus G51 laptop as the OP, then keep in mind that the G51 also offers a 9-cell battery option which should boost your battery life to 2-2.5 hours.

 

So if I want 3+ hours from an external I need something with at least 100Wh or 5000+ mAh correct?

 

OP,keep in mind I asked the very same question when I began contributing to the forum.Being located in Bangalore and all its power cuts,I too wanted an external battery to add runtime(here,a UPS with your desktop is an obligation.Mine took so much battering with all the power cuts that I fully used APC's 2-year warranty with multiple battery changes).As at the time nobody could really help,I did some searching of my own,and,while David is technically correct re:the rating,manufacturers themselves recommend NOT using a 90W rated batt with a notebook which can draw more than that,citing potential damage(or lappie not even turning on).They say U can use the external 90W-rated battery to recharge lappie's one when lappie is off.

Furthermore,it seems the max rated external batts available on the market right now are 90W-rated,nothing beyond that.At least I didn't find any.That's why I gave up on this and settled for the identical 9-cell G50 batts available on eBay(tip courtesy of Linuxguy).

 

Addendum:with the measly 4.5A max the linked Tekkeon can output,I'm afraid it won't do for the G51,as I initially thought.

http://www.tekkeon.com/products-mypall-specs.html