Is there any science to choosing one?

I assume that the mah figures quoted are similar to those for the bike light batteries, should I just go for the cheapest?

I’ve had two, 1st lasted 1yr and the 2nd still going (2yrs on) Though to be fair I don’t use the Lappy as much as I once did…
No science, just bought the best one with best part of 100% feedback..
Lappys an old Dell BTW.

I got a replacement for Mrs.TRH’s Dell from Amazon. It’s much better than the original.

No doubt others will be along to say it’ll be fine, but…

A laptop battery is something I’d only get from the manufacturer. Aside from the risks of getting a lower than advertised capacity, it’s the risk of fire/explosion that bothers me more.

Wh is a better measure of capacity, mAh is only relevant if you’re comparing like-for-like voltage wise. Wh is the normal measure for laptops.

It’s pot luck. I’ve had good ones and bad ones. IMO the risk of fires, etc is overstated with laptop batteries as it’s usually the charger that causes the problem and that part is built into the laptop, not the battery.

Pot luck, I think. Lots of fakes in the battery world on Ebay.

My last punt for our aging laptop (hence just wanting a cheapie to make it work) turned out ok and is still going strong 3 years later.

mAh is only relevant if you’re comparing like-for-like voltage wise.

i.e. 100% relevant if you’re replacing a battery with another of the same voltage, as you would in a laptop.

How about getting yours rebuilt with known brand cells? Been tempted to do it for one of my old laptops.

Does anyone know if the electronics need resetting when you do that?

Not sure i’d be bothered with getting this one rebuilt, dont use the laptop much really. Normally leave it plugged in when using but iv’e just got the interface to read fault codes from my car so a decent battery would make that a lot easier.

I’ll just go for the one with the best feedback then!

Got one for the missus laptop, and a charger.

Neither has exploded or caught fire.

Battery lasts as long as it should, although it’s hardly used anymore, but works OK when it is.

Both were considerably lighter than the originals though, presubably they skimped on heat sinking as it’s not short on current or capacity.

The connector is a bit duff, it doesn’t click into the laptop, or even have a tight fit just sits in the socket and falls out occasionaly.

When it comes to replacement laptop batteries not all the cheap ones are nasty and not all the nasty ones are cheap, but seem to be a lot of bad batteries out there.

I’d want to buy a battery from a proper reseller with good feedback, not just someone with an Ebay account and a spare bedroom full of Trotters Independent Traders finest.

i got one, for a dell, its lasted 3 years, unlike the original which went from absolutely fine to absolutely dead exactly 1 month after the warranty ran out. (coincidence?)

Can anyone that’s had a good ‘un link to the seller they bought from?

I got a cheap ebay one for 30 quid ish for a Dell. Initially it was great, held its charge fine, lasted the expected time. But it rapidly lost its ability to hold a charge and after 6 months didn’t hold any charge at all 🙁

I used this to monitor it…
http://batterybarpro.com/

Previous Dell battery lasted around 3 years or so.

Not sure how you find a good one. do any non-eBay ones come with a guarantee?

I’ve recently got one from fleaby, it was the cheapest I could find (£12ish) with decent seller seller feed back and it works fine. I’ve killed 2 laptop batteries by leaving it plugged in 24:7 so I’m trying to be a bit nicer to this one and not have it at 100% charge all the time

We bought one – not the cheapest. It was crap – about half the capacity of the original 🙁

I’ve killed 2 laptop batteries by leaving it plugged in 24:7

I don’t think you have.

I don’t think you have.

I do

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Not sure how you find a good one. do any non-eBay ones come with a guarantee?

There are some anker ones on amazon that come with a 1 year warranty.
Little bit more money than eBay’s cheapest.

I do

I was reading those links and thinking ‘I still don’t think you have’ and then I found this in the first link:

“Should I disconnect my laptop from the power grid when not in use?” many ask. Under normal circumstances this should not be necessary because once the lithium-ion battery is full the charger discontinues charge and only engages when the battery voltage drops. Most users do not remove the AC power and I like to believe that this practice is safe.

So now I really don’t think you have 🙂

Overcharging is not good for LiIon batteries, for sure, but your laptop is not always charging the battery when the power supply is plugged in. It’s clever enough to realise that the battery is full and stop charging, and then apply the required top ups when needed.

You only need worry if your battery is getting hot. Mine isn’t.

I’m still right 😉

“Commercial chargers do not allow changing the charge voltage limit. Adding this feature would have advantages, especially for laptops as a means to prolong battery life. When running on extended AC mode, the user could select the “long life” mode and the battery would charge to 4.00V/cell for a standby capacity of about 70 percent. Before traveling, the user would apply the “full charge mode” to bring the charge to 100%. Some laptop manufacturers may offer this feature but often only computer geeks discover them.”

also

“Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion, a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling.”

It was over the space of about a year but a laptop battery permanently at 100% charge and sitting in a hot laptop or 20C living room will become knackered much quicker than if it is kept at a lower state of charge and as cool as possible. Overcharging kills them very quick but that’s a different issue.

You are right in that there are some things you could do to extend the life. However your original comment suggested that you should be unplugging your charger once the battery’s full, which means a) faff and b) running it on battery all the time, only pausing to charge it up. Which will kill your battery much more quickly.

The best advice is if you are using it on AC all the time remove the battery.

I don’t think you have.

I do

I do too. Bought a replacement for the wife’s Dell (Dell battery, but from Ebay), she never unplugged it and the replacement lasted about 2 months.
Unfortunately, it didn’t explode though.

For balance I don’t 🙂

Have had loads of batteries on loads of laptops, all treated ‘badly’ some lasted 4 year some 4 months. All down to luck.

It may have failed even if you hadn’t plugged it in though – that’s what you don’t know.

Also buying a ‘Dell’ battery from ebay you have no idea if it’s really a Dell one, or it’s a ‘reclaimed’ one or it’s a new case filled with reclaimed cells.

Cells do randomly fail.

Another thread that might be useful?