Battery Specs: What Do They Mean

[Carbo]

I need the help of someone with smarts about batteries. Now, this has nothing to do with flashlight batteries, so please forgive me, but I'm not sure where else to go for info.
My Dell laptop battery died two days ago. The existing OEM is a rechargeable Li-ion battery with the following specs: 11.1V, a capacity of 90Wh, and 8400mAh.
The replacement I'm looking at: 10.8V, a capacity of 84Wh, and 7800mAh.
In the real world, will there be a drop off in performance?
By the way, the OEM is only 15 months old. Is this the normal life expectancy of these batteries? Is there a usage pattern that might increase performance and life?
Thank you, gentlemen!

 

[SilverFox]

Hello Carbo,

Yes. You will see about an 8% drop in run time.

You must have a bad cell in your pack. Usually these packs run for at least 3 years before giving it up. However, the life depends upon use. If you have been completely discharging and charging your pack twice a day for 15 months, you probably wore it out.

Tom

 

[Carbo]

SilverFox, appreciate the reply. Thank you.
I was on the phone with Dell today, griping that 15 months is a rather short life. They insisted that one year is the life expectancy and, of course, the warranty covers just that. I'm a bit peeved because the cost at Dell is $180! I've been looking for a comparable replacement but haven't yet been able to find one.

 

[Aquanaut]

I've been looking for a comparable replacement but haven't yet been able to find one.

Enter "Dell 'your laptop model' battery" in Amazon, and you will get a much cheaper choice for your battery. Dell OEM batteries are over priced.

 

[Robin24k]

Check eBay for genuine OEM batteries, even though it only lasted for just over a year, aftermarket batteries tend to be even worse. What model laptop is it?

BTW, usage has a lot to do with battery lifespan. Remember that Li-Ion batteries are only good for about 500 cycles, so if you frequently discharge the battery, you'll reach 500 cycles in about a year. Since I have my laptop docked most of the time, the OEM battery is about three years old and still holds a charge just fine.

 

[Carbo]

Enter "Dell 'your laptop model' battery" in Amazon, and you will get a much cheaper choice for your battery. Dell OEM batteries are over priced.

I'll check out Amazon. At $180, I can't argue with your assessment of Dell.

Check eBay for genuine OEM batteries, even though it only lasted for just over a year, aftermarket batteries tend to be even worse. What model laptop is it?

BTW, usage has a lot to do with battery lifespan. Remember that Li-Ion batteries are only good for about 500 cycles, so if you frequently discharge the battery, you'll reach 500 cycles in about a year. Since I have my laptop docked most of the time, the OEM battery is about three years old and still holds a charge just fine.

It's an XPS15, (L501X). Not a big fan of Ebay, but I'll have to give it a look since this battery has proven to be more elusive and expensive than I anticipated.

 

[yifu]

The permanent loss of capacity in a Li-on is usually around 5-15% per year depending on storage conditions. If stored at low temperatures it's usually closer to 5% however discharging it at more than 60 degrees celsius will yield the most capacity. Looking at the data sheet for the Panasonic OEM NCR18650(most battery packs use 2600s), the capacity drops by about 25% after 300 complete discharge cycles (down to 2.5V), so i would expect at least a useable 500 cycles? Of course some laptops like MacBooks use a different chemistry that allows for 1000 complete cycles.

 

[Aquanaut]

BTW, usage has a lot to do with battery lifespan. Remember that Li-Ion batteries are only good for about 500 cycles, so if you frequently discharge the battery, you'll reach 500 cycles in about a year. Since I have my laptop docked most of the time, the OEM battery is about three years old and still holds a charge just fine.

+1

My aftermarket replacement laptop battery is still going strong after about a year, but my laptop is mostly docked.

It's an XPS15, (L501X). Not a big fan of Ebay, but I'll have to give it a look since this battery has proven to be more elusive and expensive than I anticipated.

I just checked Amazon, and I saw a replacement for $90.

 

[Robin24k]

There's an OEM replacement on eBay for $85, but it's from an international seller. If you can find a new genuine OEM battery from a US seller, it'll be a safer bet.

http://www.ebay.com/itm/120710526164

 

[Quest4fire]

Proper thermal management is another big issue for laptop battery packs. Excessive or persistent high temps will exacerbate any issue with a pack, and will shorten pack life regardless. Cool things down as much as possible!

 

[Mr Happy]

If you are in the USA, check with Batteries Plus. They may be able to rebuild the original pack for you with good quality replacement cells. It could be worth a try, since aftermarket replacement batteries may be a bit of a lottery where quality is concerned. You could find a non-Dell replacement dies even more quickly than the original.