9-cell Battery question

Just got my new battery from Hong Kong. It was advertised as a 7800 mAh battery - same as Lenovo's OEM nine-cell battery.

Here's what Lenovo diagnostics has to say about it though:

Lenovo ThinkVantage Toolbox Log File

Friday, February 04, 2011 7:56:23 PM
Main Battery
Battery Name: 42T4522
Manufacturer Name: SANYO
Manufacture Date: 09-27-2010
First Used Date: 06-15-2009
Type: LION - Lithium Ion
Bar-coding Number: 1Z10D02109U
Battery Serial Number: 1577
Designed Capacity Percentage: 100
Current Charge Percentage: 96
Current Charge: 67.79 Wh
Full Charged Capacity: 71.28 Wh
Designed Capacity: 71.28 Wh
Voltage: 12.51 V
Temperature: 20 C
Cycle Count: 1
Battery Status
Test Started 2/4/2011 7:55:40 PM
Test Finished: Passed 2/4/2011 7:55:40 PM

What's got me confused is that diagnostics gives its design capacity in watt hours (71.28) and the battery was advertised in mAh (7800). Multiplying the voltage by the WH is supposed to give me mAh but in doing that I'm getting nowhere near 7800 mAh.

Another complication is that the battery is advertised at a voltage of 10.8 but diagnostics is showing a voltage of 12.51.

Can any of you electrical whiz people figure this out just what I got for my $39.99 with free shipping? I'm thinking I got a good battery in any case, but I'm also thinking I didn't get what was advertised.

Thanks.

 

Send seller info about mAh, voltage and capacity and ask them for partial refund
I can only comment on quality of generic rechargeable AA/AAA sized batteries that Ive used for cameras - they suck and are of 2-3 times lower capacity than advertised and drain out pretty quickly during time even if not used.
I suspect they will fail very fast. Not sure how its with Li-on laptop batteries, they might last longer than your average NiMh batteries but probably will last lot shorter period of time compared to original Lenovo batteries.

Id say first contact about item not being as described and then, if you use it and notice some degradation that is too fast contact seller and request for more refund/full refund while you can (depending on paypal/cc/ebay feedback policies)
They all claim 2-3 years warranty to attract buyers on these laptop batteries, Ive seen it on ebay, yet I highly doubt that those batteries will last longer than 6 months till they wear out completely.

 

I did question the seller and he explained that they can advertise such a high mAh rating in the same way that hard drive sellers advertise larger capacities than what is actually available after formatting. Naturally the logic is faulty but I want now to give the seller the actual mAh rating based on the diagnostic readout of 71.28 watt hours. I'm not smart enough to figure out just what the actual mAh is using the Wh x voltage = mAh formula, one reason being that the battery is advertised as producing 10.8 volts and the Lenovo diagnostics says it's producing 12.51. The same diagnostic program (Lenovo Power Manager) also says the battery is design rated at 10.8. Why is it producing 12.51 then?

Diagnostics also says the battery is made by Sanyo - not exactly a no-name brand.

I'm sure getting a genuine Lenovo rated at 7800 mAh (has anyone actually run a diagnostic on a new Lenovo nine-cell battery just to see what comes up?) would be the best thing to do, however they cost at least twice as much.

If anyone can figure out just what the actual mAh is for this new battery from the info I've given I'd appreciate it. I'd like to have some solid info for the seller when I respond. I don't think I'll be asking for any refund since it looks like I got a pretty good battery for $39.99 (free shipping) in any event. Time will tell, but so far it seems fine. With 100% charge it shows almost 8 hours in power-saving mode. I do however want to bring it to the seller's attention that he is mis-representing his product. Actually I already did do that, just without any specifics. That's when he came back with the hard-disk analogy.

Thanks for the response.

 

71.28wh/12.51v=5.7Ah
5.7Ah=5700mAh

Its like this, I believe
Even if the voltage would be the correct one 10.8 volt you would still have battery with 6600mAh capacity which is 1200mAh lower than advertised.
I say you should stand your ground and make the seller either give you replacement (which probably will be with the same specs) or refund, either partial or full depends on sellers return policies.
As long as you dont have to put your money into returning this battery any solution should be fine.

And it comes as no surprise for me to see that its much lower than actually advertised, just like with every chinese knock-off product