of secondary importance

Perhaps something useful..  a quick cheat sheet on the care and feeding of the rechargeable batteries in your devices.

 

For historical reasons rechargeables are known as secondary batteries and one non-rechargeables are primaries.  We may complain about constantly having to charge everything, but you'd have to spend a few bucks a day to power your smartphone on primary batteries ..  you'd end up sending the bunny about as much money as you send Apple or Samsung.

 

I'm not going into any depth on the various battery families and where they're appropriate. Lithium-ion refers to a very broad category with hundreds of types of batteries, while nickel-cadmium, nickel-metal hydride and lead-acid are much more specific terms.  I'm only going to talk about lithium-ion and lead-acid as they're the most common types most of us use daily.   

 

lithium-ion tips

 

Don't swing the charge too much if you can avoid it.  The innards of the battery expand and contract during charge and discharge  by as much as ten percent.  This results in cracking that lowers storage capacity  Most smartphone and laptop batteries are rated to retain at least 80% of their original capacity after about 500 charge/discharge cycles.  This generally assumes a usage pattern where you rarely completely charge the battery and rarely discharge it to under 20 or 30%.    If you try to stop charging around 80% and never drop below 30%, you should be able to double the battery's service life.  Conversely dropping to under 10% capacity most of the time followed by fully charging can drop the service life to 100 cycles or less.

The best rate to charge a lithium-ion battery depends on its state of charge and varies throughout the charging period, battery history, and a few other things.  Fortunately you don't have to worry about this any more as most name-brand phones and laptops have smart chargers that measure and sometimes even chat with the batteries.  Stay away from third-party chargers.  Not only are you likely to shorten battery life, some have proven to be serious fire hazards.  

Temperature is important.  Below about 40°F capacity drops dramatically.  Fortunately there isn't any damage unless they get really cold.   Heat is another matter.   Anything over about 95°F (35°C) will begin to cause permanent damage.  Not much at first -- constantly keep your phone in your pocket against your body and you may see a 20 or 30 percent drop in cycle life - but a few hours at 110°F (43°C) can kill a battery.   You don't need to live in Phoenix to get to this type of temperature in the Summer - just leave your device in your car on a sunny day.  If you're spending time in hot weather and carry your phone in a bag, it makes sense to put it near a cold pack.  Note that warranties do not cover batteries for excursions beyond rated temperatures and some devices track that.

And if you have to store your device for a long period - a month or more - store it in a cool place (below room temperature if possible, but not in the 'fridge) with a half charge.

so ...

don't overcharge

don't swing them too much

keep them cool - I tell people to treat handle like good chocolate (except don't eat them)

use the charger recommended by the device's manufacturer

 

lead-acid tips 

 

This  is the battery under the hood of almost every car with an internal combustion engine.

Keep them charged.  Your car usually does a good job when the engine is running.  Some of the discharged materialis transformed to a new state from which it can't be recharged. There is a  failure mechanism known as sulfation where some of the discharged material is transformed to a material that can't be recharged.   This takes place slowly over the life of a battery, but can be accelerated to a matter of hours if you allow the battery to fully discharge.   I remember my father accidentally leaving the lights on during the day only to come out to a dead battery eight hours later.  There is a small discharge that runs some of your car's resting electronics, but it isn't a major drain.

If you're away from your car for more than two weeks you should have someone start it up and run the engine for at least fifteen minutes.  If it is a few months you should follow instructions for long term storage (this also applies to other parts of the car).  When I'm away for extended periods I disconnect the battery to halt the small drain from the car's electronics. 

 In the cold weather it is much more difficult to start a car - the oil is more viscous and the starter may take so much energy that abnormally large amounts of sulfation take place.  Also the amount of power a battery can deliver drops.  Keeping a car above freezing for starting can make a big difference.  In cold Northern climates it is common to keep the oil warm by heating the engine block with a 1000 to 3000 watt heating element.  My father called this approach his "poor man's garage".

If you're really careful with the charging cycles and temperature a lead-acid battery can easily go 30 years.  This isn't possible in the more compromised environment your car has to live with.  Figure on replacing the battery in warm climates every six years and every five to six in colder regions.  If you manage to completely drain the battery - even if it is new - just replacing it makes sense.

 

Batteries are getting better, but other than cost it is a slow game.  Don't expect dramatic improvements in the next five years at a minimum.

 

Comments

[Jheri]

The heat killed the battery in my three month old iPad. I left it in a black car in Spain last Summer for three or four hours. Afterwards it would only hold a charge for a half hour or less. Apple replaced the battery under warranty.

[AG]

would you recommend amazon basics cable for iphone.