Battery usage: Recommendations

Hi Guys,

Let's talk about batteries today, the most complicated chemical devices we use every day. Most of batteries used in Laptops and mobiles are Li-Ion (Lithium Ion), some mobiles/laptops use Li-Polymer batteries which are little better than Li-Ion one but not that much. Here are some recommendations for Li-Ion batteries used in laptops which if followed can greatly save battery life. These recommendations are equally applicable for mobiles but due to their usage models it's not possible to follow each of these in case of mobiles.

1. Always fully discharge and recharge battery once in 10-15 days but not daily.
   
2. Never deep discharge a battery; beyond 1% for more than 1 hour or so.
   
3. Make sure that battery is at least 40% charged when need to store for more than 4-5 days, for longer period charge fully.
   
4. Most Li-Ion batteries have around 450 charging/discharging cycles and/or around 24 months life (whichever earlier); so use accordingly. At this point battery capacity becomes about 50% and will gradually decrease after this. So in case of laptops run it on battery only if necessary.
   
5. Heat is one big enemy of Li-Ion batteries; so keeps them away from heat, atleast from direct sunlight, and other heat sources like ovens, invertors etc.
   
6. Only charge a battery when remaining power is less than 50%. Say you unplug your laptop just to move to another room, then it's recommended not to plug it immediately. Let the battery discharge and when it reaches 40-50% then charge it otherwise it decreases battery capacity. This is applicable to Li-Ion batteries and is called as memory effect, here battery actually forgets its full capacity and in future may not charge upto its full capacity. Though this don't happen in single time but if you charge your battery from 80-90% multiple time then with time your battery might never charge beyond 80-90% of its capacity though the status will be fully charged.
   
7. NEVER short circuit a Li-Ion battery. Laptops batteries have internal circuit to protect the battery in case of short circuit but mobile batteries do not have any protection and may explode in case of short circuit. Explosion rarely happens but yes life decreases exponentially with each second in case of short circuit.
   
8. Overcharging also kills Li-Ion battery; as said laptop batteries have internal circuit for this so you can keep your laptop plugged to mains as long as you want but for mobile phones don't have this protection so don't leave you mobile on overnight charging.
   
9. If you want to go on a leave for say 30 days, then fully charge the battery and keep it in a cool place like wooden box.
   
10. First charge a new battery for 4-6 hours before using. First use without charge can greatly affect battery, so before using your new laptop/mobile for first time don't forgot to charge the battery fully.
    
11. Humidity affects component connectors, so keeps your laptop/mobile away from humid environments. Thing is not that its not recommended to take your laptop on a hilly area, thing is sudden change in humidity affects electrical connections, so don't talk laptops/mobile in toilets unless necessary. Well almost all battery connectors are gold plated but they are not sufficiently thick so do take care of humidity factor.
    

 

So that's all, below are some answers to very simple and good questions which i have answered multiple times:

1. There is absolutely no harm to a laptop if you keep it plugged required it is receiving quality AC current. As said laptop batteries have inbuilt circuit to take care of it but this thing is not applicable to mobile phones so unplug mobile from charger as soon as it gets fully charged.
   
2. You want to download something overnight, absolutely no problem if you keep your laptop plugged to mains.
   
3. Never disconnect a laptop battery if it is plugged to mains even if laptop is powered down. First disconnect charger from mains and then remove the battery.
   
4. Every laptop battery has number of cells and its common impression that 6 cell batteries have 1.5 times capacity of 9 cell batteries. Well while buying a laptop never go for number of cells, look for capacity as capacity of individual cells is what matters. Capacity is mention in WHr (Watt Hour) or mApm (milli Ampere), if you today (Nov 2009) buy a laptop with standard config without dedicated graphics then a 50WHr or 4000mApm battery will give you about 3.5 hours of battery life, so take this as approx matrix and decide accordingly.
   
5. Well most laptops can work directly from AC without batteries but don't do this unless necessary.
   
6. Some laptop manufactures like Dell will give you option to choose a high power charger or some manufactures have super charge feature which decreases charging time. Well this also decreases battery life, yes you can charge a battery in less time by charging it at more voltage but a battery can handle only a specific current rating at specific voltage, increasing any of these decreases battery life. So choose these fast charging options only if absolutely necessary.
   

 

So Guys these are all some simple facts about laptop/mobile batteries, if you have any doubt then do ask in comments and do share your views.