Laptop Bateries - What is 58 WHr?

  OK. The electrical explaination makes sense but why would someone choose the 6-cell 58 WHr over just the regular 6-cell. ARe there any advantages to the 58 WHr?

A regular 6 cell battery is around 47 Whr while a high capacity 6 cell is 55Whr or more. That's why some need to specify it as 58 Whr.

I didn't correct anything. All I have done is ask questions :)

Whoops -- sorry about that.   I meant armchang's "correction" was wrong :-)

Lol. Really? then I need to disappoint you as my findings are backed up by my reference. Please read my post again. Either way, I think no batteries are based on WattHr and not Watts only as a measurement unit of how long charged batteries will last.

Rewrite: Either way, I think batteries are based on WattHr and not Watts.

Battery capacity is indeed measured in watt-hours => a standard unit of measurement computed by simply multiplying the watts you're drawing by the hours you draw it.

Neilsr's example, which you incorrectly said was wrong, was "... if you draw 58 Watts it will run for 1 hour, 29 Watts 2 hours."

Note that if you draw 58 watts for 1 hour you have consumed 58watts x 1hr = 58 watt-hours.
If you draw 29 watts for 2 hours, you have consumed 29watts x 2hrs = 58 watt-hours.

So ... as Neilsr correctly noted, with a 58 watt-hour battery, if "... you draw 58 Watts it will run for 1 hour ..."   and  if you draw "... 29 Watts" (it will run for ) "2 hours."

Okay, I retract that.. but isn't it irrelevant to use Watts when the measurement is WattHrs?

I agree that it isn't wrong, my bad but going back to the question from the author, NeilsR example doesn't help the author to determine which battery to choose, I think my suggestion is much more better that his.

NO -- the power consumed at any given instant in time is measured in watts.

Watt-hours is a measure of the total energy consumed over time.   It's used to state the capacity of batteries, so you can reasonably estimate how long they'll last for a given load.    e.g. if the load is 29watts, and the battery's capacity is 58 watt-hours, then the battery can sustain that load for 2 hours.

From ehow.com:

The more WHr, the longer the battery will last between recharges.

From this saying, it says that if you have 58 Whr battery and the laptop is drawing 58 Watts => then your battery will last 1 hour only. (Which neilsr also explained) but another scenario from ehow.com says that if you have 116Whr battery and the laptop is drawing 58 watts=> then your battery will last 2 hours.

For the 2nd scenario if the battery is 116Whr and laptop is drawing only 29 Watts => then it will last 4 hours.

Anyways nobody is wrong here. :)

As for the author's questions ...

"... What does the "58 WHr" do for you? "  ==>  It's simply providing more detailed specifications than the other battery does.    As I noted earlier, I suspect they're identical batteries from different suppliers ... probably with the same capacity (58wg)

"... why would someone choose the 6-cell 58 WHr over just the regular 6-cell " ==>  Again, it probably doesn't matter;  but between the two you listed I'd buy the 58wh battery so I KNEW what I was getting in terms of capacity.     Actually, I wouldn't buy ANY of the batteries you listed.   You can get a 5-cell, 58Whr battery for $81, or an 8-cell, 77Whr battery for $90, here:
http://www.atbatt.com/laptop-batteries/b/dell/m/vostro-1710.asp?utm_source=google&utm_medium=ppc&utm_keyword=Dell+Vostro+1710+Battery&utm_content=LDE-84XT&utm_campaign=google0&gclid=CJHT25OvoawCFZJS7Aod5hVHDg

"... Anyways nobody is wrong here. :) " ==>  While perhaps you now understand how it works, your original comment ["... Neilsr's answer is correct except for the example..."]   was clearly wrong.    I simply corrected that.

Yes I was wrong and you've proven that. Thank you.