Laptop Batteries - mah, WH, what? why? 2

[kjv1611]

Okay, so I figured I'd post to ask about this question.

I figure more is better normally, but at what difference, what cost?

Here are some specifics:
I need to get a new battery for a Dell XPS m1530, which someone gave me.

I can find a Dell Replacement battery, 9 cell, that has 7650 mah, 85WH, for $100

I can also find many generic brand replacements, 9 cell, but they have all 7200 mah, for around $50

Obviously my question is, then, will I see a difference between the two?

Also, would the 7200 mah end up being a little safer or a little less safe, as far as handling heat, stress, etc - just by the numbers. Or do the numbers affect it at all?

Thanks for any info/advice.

--

"If to err is human, then I must be some kind of human!" -Me

 

[Nelviticus]

All other things being equal the 7650 mah battery should last about 6% longer than the 7200 mah ones. As the generic ones are definitely compatible and are good quality - i.e. they're not dodgy fakes or dangerous badly-manufactured ones - they should be fine.

Nelviticus

 

[kjv1611]

Yeah... let's see...

I could spend $50 more to get 6% more time... which is what 5 minutes?

So, mah is capacity..

I did find one reference after I posted this, which gave some detail on the specifics. Of course it was from a replacement battery seller's site, so I figured I'd take their advice with a grain of salt or maybe a whole salt block.

--

"If to err is human, then I must be some kind of human!" -Me

 

[Nelviticus]

'mah' is 'milli-amp hours', so 7200 mah means it could supply 1 milliamp (ma) for 7200 hours, 7200 ma for 1 hour, 72 ma for 100 hours or any other combination.

'WH' is 'Watt hours'. Amps are a measure of current, Watts are a measure of power.

So yes they're both measurements of battery capacity - the higher the number, the longer it will last before needing a recharge.

Nelviticus

 

[manhunter2826]

^Thanks nel, very useful info. Does this mean the six-cell batteries (supplied by some netbook manufacturers like the Samsung NC10) are the best in terms of longevity??

 

[Nelviticus]

Well, generally the more cells the better but not always so - six very low capacity cells might not be as long-lasting as four very high capacity ones. The mah rating is more relevant than the number of cells if you're just interested in capacity and not in how large/heavy the battery is.

Nelviticus

 

[manhunter2826]

^Thanks again nel.

 

[kjv1611]

Quick post follow-up.

I got the $50 9 cell battery - from China or Hong Kong. It took about 2 weeks from time of order, but did come in. It's now giving about 5 hours run time for an XPS m1530 with nvidia 8600 graphics, Core 2 Duo @ 2GHz, and a WD Black 7200 RPM hard drive.

--

"If to err is human, then I must be some kind of human!" -Me