Thinkpad plugged in & battery?

Hello all, just got my thinkpad a couple days ago. Anyways, I was wondering whether it's okay to have the laptop plugged in and have the battery in at the same time. Would it damage the battery? shorten its life span?

thanks for answering.

 

The battery will stop charging once it's reached capacity. There should be no problem.

 

Batteries degrade fastest when charged to 100 percent. If you use the thinkpad power manager, you can optimize the battery thresholds such that you avoid having the battery at 100%. For example, you can set the maximum charge level for your battery to 85%. Or you can set for your battery to charge only when under 25% and to charge only to 85%. I used to micromanage such that I kept my battery charge around 35% when plugged in, charging the battery up only when I knew I would need the battery. Nowadays I just use a 20%-80% threshold. After 2 years, several months, and 181 cycles, I am at 90.7% of designed battery capacity.

I don't bother ever removing my battery because the temperature difference between room temperature and plugged in battery temperature is not very significant.

 

Yes, Battery Maintenance in Power Manager lets you select your own charge limits.

Also be aware that a quirk in the Thinkpad BIOS means that your CPU speed will probably be throttled if you remove the battery.

John

 

sorry for not understanding, but are you saying yes it won't harm the battery and is safe to have the thinkpad plugged and the battery in at the same time. Or are you saying yes it will damage the battery? Just wanted to clarify because I'm a new thinkpad user.

 

John, I might not know how to check properly, but it doesn't seem to happen to my T420. I checked by looking at the System properties in the Windows control panel, and also by using CPU-Z. I'm using the "Power Source Optimized" plan, with "Balanced" CPU performance on battery. Do you think it's happening and I'm not realizing it, or maybe that Lenovo fixed it recently? I can't tell a difference in performance on battery so far, but I tend not to run heavy applications on battery anyway.

ETA: I'm a dunce. The battery was in, and I didn't understand what I read.

 

That "quirk" in the BIOS is a feature to prevent over-run the ac adapter. Granted a 65W AC adapter should be able to handle the the Intel GPU and other stuff just fine but there are random spikes when doing some full intensive stuff with some USB powered devices where the system might pull close to 60watts. If you are grinding away at higher wattage the system will pull some juice from the battery in order to not blow the AC adapter and cause a fire or something.

So in order to mitigate that lawsuit, the system locks the CPU at a lower speed when there is no reserve power available.

As for topic stuff though, you should be more than fine. Thinkpads run cool as it is anyways and the major danger to batteries are heat. Charging to 100% in my experience doesn't do any hurt at all.

 

Yes = no harm. The BIOS won't overcharge the battery but, for more precise control, press the Battery Maintenance button on the Battery page in Power Manager. Then select the custom charge option and select (for example) start charging at 40% and stop at 80%.

John

 

Great, Ive set my thresholds to 30%/60%. But when its plugged in and with the battery in at the same time, the battery doesn't seem to be discharging? and its not charging either. Is that normal?

 

If you set it for 30/60 and you're plugged in, it will only start charging when you drop below 30% and charge up to 60%, then stop. It will take a long long time to trickle back down to 30% from 60% when running solely on AC so you won't see charging for a bit. I have mine set at 45/55 because it's plugged in all the time but when I plan to take it somewhere, I'll switch it to 95%.