will charging over night hurt the battery?

will letting my t420 charge overnight hurt the battery? i heard letting a battery charge past 100% hurts the battery.

 

By default, Power Manager automatically keeps it at safe level around 96-98%, so no worries about that.

 

EDIT: I was wrong, secondary batteries are protected as well.

 

The batteries used by Lenovo are "smart" ones: they know when to stop charging. This capacity, together with the parameters maintained by Power Manager, keep the battery in good shape. You can set the parameters to indicate when to start and when to stop charging ("when" meaning "percentage level").

 

That doesn't seem to be the case with my X220. The default setting of 'automatically optimise for battery lifespan' charges to 100%. Strangely, it did go through a short phase of only charging to 98% for a couple of days but now goes to 100 again.

Seems like that's the only way to stop it charging to 100%.

To the OP, once the battery is fully charged, or charged to the level set, it automatically stops charging. So you don't have to worry about over-charging it. Even my phone does the same.

 

Something I just though of: when the system is powered off does it stay true to these thresholds? Mine are set to 90% / 98%, and I have never checked if it stops at 98% when shutdown. Does the battery "know" when powered off when not to start charging (over 90%) and when to stop? (98%)

 

The charging thresholds are stored in the battery controller, so the controller decides to stop charging. Power Manager simply sets threshold values on the controller. This is also why you can set a threshold and uninstall Power Manager but still have the battery charge with the threshold restrictions.

 

I have mine set to charge to 85%, not an issue for me :shrug:

 

Thanks, I was sure that must have been the case, but I hadn't played around with it enough to know.

 

Where in the software can I go to check this setting? Mine is charging to 100% and I'd like to set it to 98% since I've read that that's a good way to go.

 

Power Manager -> Battery tab -> click Battery Maintenance button and you will likely see that it already uses the right setting "Automatically optimize the battery lifespan" but you can play with other settings if you're bold

 

Thanks for that. Mine is set that way but still shows "100%" on the battery. I guess it's just a display thing.

 

Yeah, it's 100% initially and then will be slowly discharging over time.. personally, I'm happy with this logic but you could set it to the custom threshold if you really want to prevent it from charging to 100%.

 

The display shows it as 100%, but it's really only charged about 98-99%. That way people who don't know aren't constantly complaining to Lenovo that their batteries won't charge all the way.