Yesterday, by pure chance, I ended up reading an interview with a Li-Ion battery specialist. I was quite impressed (and scared) to hear that continuous full charge/discharege of the battery will ruin their life, and that is a best practice to plug it before it goes under 20% of the charge and unplug it when it reaches 80% charge.
I wanted to post a link to that source but in some way I cannot find it anymore. With google anyway I’ve found many trustable sources with suggestions on how to preserve the life of li-ion or li-ion polymer batteries. A short summary of their tips is listed below, I hope it can be of help to other people.
At the moment I am developing a small applet for Mac OSX that reminds me to connect and disconnect the battery when it reaches the proper level. I will upload it soon on github, if you are interested stay tuned.
Good practice in a nutshell
- Optimal battery use is between 20% and 80%: aim to discharge to ~20% then charge to ~80%
- Full discharges damage the battery: try to avoid discharging to below 10%
- Keeping the battery at 100%, i.e. keeping it plugged in to the charger, damages the battery (through being at 100% and because it’s likely to be hotter when plugged in)
- Humidity damages the battery: keep it dry
- Heat damages the battery: keep as cool as possible at all times but above 0 degrees Celsius and avoid the fridge/freezer
- Li-Ion batteries don’t have a memory: they don’t suffer from frequent small charges
- To re-calibrate the fuel gauge of your battery (improve battery level reporting, not battery memory): fully discharge it approximately once a month, or once every 30-40 charges
- It is better to charge the battery with the device turned off
- If you need to store the battery without using it for a period of time, discharge to 40-50%
To remember to make a full discharge once a month Apple prepared a downloadable calendar event. Just open it in your favourite calendar application and it will set up a monthly reminder.
Hopefully these tips should help you to extend the longevity and the capacity of your li-ion batteries, on the other hand it seems pretty clear that these best practices are hard to follow.
For additional informations have a look at the following links:
- Battery University: Charging Li-Ion Batteries , How to Prolong Lithium Based Batteries
- Gigaom: Extend the battery life of your MacBook, no matter how old it is
- Fergyblog: How to Prolong Lithium-Ion Battery Life
- Ars Technica: What is the Best Way to Use a Li-Ion Battery?
- Geeknizer: How to Extend Battery Life
It’s just a status bar application for MacOSX 10.8+ that fires notifications to inform you when to plug or unplug the battery.
Somebody made a sort of version with steroids of my app. IMHO it is quite expensive, but if you are interested, you can download it from the AppStore