After market battery for NV79

My original battery says part number AS07B31, Rating 10.8 v

But the only two models available on e-bay say 14.4 v or 11.1 v.

What should I be buying or is there someplace to buy the correct battery without pay high prices?

 

Buy the 11.1V battery. Don't fret too much about it being listed at a slightly different voltage. They all use lithium ion cells and the voltage changes a lot between fully charged and drained.

The 14.4V battery is either a typo, not the battery for your laptop, or is a 4 cell battery and not as high capacity as the 6 cell you have now.

 

Thanks for the prompt answer!

 

No, the 14.4V model is (probably) not a mistake.

A battery can increase the wattage/runtime it has by increasing the voltage, for example.

See:
http://forum.notebookreview.com/7766806-post2081.html

If the OP could give more details of all the parts involved, better answers can be forthcoming.

 

If it has 14.4 volts, it means it has 4 batteries in series. This would only happen on a laptop that normally has a 6 cell battery if it just has 4 cells. Bad news.

 

It can also mean it uses different/better batteries too.

And/Or simply a different internal wiring serial/parallel configuration too.

 

No, it can't. All Li-Ion cells have a nominal voltage of 3.6-3.7 volts. No more, no less.

14.4 volts means 4 cells in series and 11.1 volts means 3 cells in series. On ALL laptops that have both batteries with 4 cells AND 3 cells in series, the battery with 4 cells in series is the low end one with only a single set of 4 cells in series.

 

Qing Dao,

you obviously have a lot of knowledge about batteries (most likely more than me) - but how complete and up-to-date is it?

Do I have 15/3.6=4.17 cells in my U30Jc then?

 

There is really nothing to not be up to date on.

As the cells drain, their voltage goes down, and as the cells charge, their voltage goes up. So the 3.6-3.7 volts is just what is considered their nominal voltage, even though in use the actual voltage supplied will vary from this. The 3.6-3.7 volts is what is used in calculating the nominal voltage of the battery pack. The peak charged voltage of each Li-ion cell however is maxed out at 4.2 volts before it is damaged, and in practice that is usually a little less. Any more and the cells will be damaged.

For example, my Asus has a 6 cell battery pack rated at 10.8 volts. That is two parallel series of three cells each rated at 3.6 volts. However, when fully charged, the battery pack is at 12.5 volts. That means 4.166 volts per cell.

In your case I find it odd that your battery is not rated at 14.8 volts. But it really doesn't matter anyway, since all the basic Li-ion chemistry is the same.