Your thoughts of overcharging a laptop battery?

Does it hurt the battery? or was that in he past? and the new batteries don't get affected by overcharging?

 

u cant overcharge it . the power stops coming after 100 percent change

 

Exactly, modern charging systems prevent overcharging. After the initial charge cycle, they go into a trickle mode that just keeps the battery topped off.

 

Ahh crap! I used to always remove the battery once it fully charges, bitof a hassle when you do it alot. LOL

Thanks for the clarification guys.

 

i still take out the battery cos from past experience on my 2 year old dell laptop where its battery is pretty much dead although i almost always use in on the plug. maybe the heat from leaving it on 24/7 killed the battery

 

That problem likely isn't due to overcharging, it's due to lack of use. Batteries need to be occasionally cycled, otherwise their life is shortened. I've seen it happen myself, my last Dell office laptop has rarely been run on battery, and the battery was shot within about a year.

 

Logically overcharging is not possible.

 

but then that means spare batteries for sale in shops will die if they are not sold within 1 year

 

No, because they weren't fully charged to begin with. But batteries do in fact have a limited shelf-life. I would never buy a battery from a shop that was more than a year old (assuming I could tell how old it was).

Virtually all modern Li-Ion batteries, particularly those expensive ones in laptops and such, are "smart" batteries. They have charging circuits which constantly monitor the voltage, current, and heat being held by the battery and generated by the charger. When the battery reaches its preset threshold, it shuts off the charger. Then every so often, the charger will turn on to "top-off" the battery with a very small charge and turn off again. I said "trickle charge" earlier but with Li-Ion's it's not technically a low-current trickle like with Ni-Cads. It's just a top-off charge that happens every 10-20 days or so probably. Therefore there is virtually no chance that a Li-Ion can be overcharged, unless the protective circuit in the battery or charger fails.

 

if thats the case would discharging it b4 storing help? i heard charge 40% is optimal for storage. I think it is better than leaving it in the laptop where heat will hurt the battery in the long run

 

40% is about right, that's how most batteries come from the factory. One of the reasons they ship batteries with a partial charge is because Li-Ion's can be drained beyond recovery -- if their voltage drops TOO low, they cannot be recharged with an ordinary charger. Again, the built-in protection circuitry helps prevent that by shutting down the battery at a safe threshold, while it still has some charge left. However if you take a battery that has drained itself to that point, and then store it away for a year (or ship it to a warehouse where it sits on a shelf without being purchased), it's very likely that it will self-discharge below that minimum threshold and will not be rechargeable. So never let Li-Ion's go completely dead and then store them without at least a partial recharge.