T520 battery starts charging when over 96%

I have a problem with the battery in a T520, if the batter is at 99%, and I connect the charger, it starts charging, even though it shouldn't start charging til the charge go below 96%.

When I set custom power values in power manager, for example, I set it to not start charging when below 95%, it respects those values, but then when I disconnect the AC and battery for few seconds, this result in the values being reset, and it starts charging when connecting at any value below 100%.

This is a 9 cells, Not Genuine battery.

I am worried that without settings those values manually in power manager, the battery would die allot sooner than it should due to over charge.

Is the overcharge protection a part from the battery circuit, or is it a part of the laptop motherboard charging circuit ?

 

This is your problem right there. Power Manager doesn't play nice with generic batteries.

Well, if you're really worried about what may or may not happen to your battery, stick with genuine Lenovo ones.

Overcharge protection *should* be an integrated part of the battery, but with a generic one...who knows.

Good luck.

 

At this point, I am not too worried about the battery itself, rather worried about the laptop motherboard if it might have an issue with the charging part.

Is there any information source about the 96% percent charge protection is enforced by the battery by default ?

 

Don't be. The board is fine.

You're mixing up two different things.

The percentage part is enforced by Power Manager which may or may not play well with non-genuine battery.

The battery itself *should* have a chip that will prevent overcharging. Genuine ones do. And generics...who knows.

Good luck.

 

Thanks for the reply, and sorry for repeating my questions, but want to make sure I am understanding

I just used the power manager to set the battery thresholds, to not charge unless below 92%, and it works as it should, and the battery now is sitting at 95% with AC connected and not charging.

However, ..
The "96%" should be enforced all the time, even if running an OS that doesn't have power manager or drivers installed, or just sitting in BIOS, so it is either enforced by the battery or the motherboard/BIOS/Charging circuit.

So i wonder, is that chip supposed to keep the battery from charging when over 96% ?

Or, what is overcharge protection ?

Is 'overcharge protection' something other than "do not start charging if over 96%" ?

 

Nope. That's not the way it works. You set the 96% limit within the Power Manager, and it only works within Windows. If you were double booting with Linux, that limit would not be enforced while running *nix.

No. Read on.

"Overcharge protection" will stop the battery from charging further once the pre-set parameters that reside in the chip within the battery are met. It will also kill the battery if it detects any signs of its overheating or going "out of whack" in other ways. This applies to genuine Lenovo batteries. With generics, you're playing Russian Roulette in this respect.

 

Ok, thanks

I will consider getting a genuine battery later on, but for now, this battery is giving descent time.

This battery is a generic no-brand, and not even from a known brand of after market batteries, it costs $24 shipped , so I doubt it having any special protection chips.