Software Development

Five tips for extending lithium-ion battery life

There's lots of press about how to conserve battery power, but not much about how to take care of your batteries. Here are a few things you can do to increase battery longevity.

In today's mobile world, battery life is precious. If you don't believe me, go to an airport and watch the road warriors. It can get downright nasty when two spot the only available outlet at the same time.

It doesn't take long to learn what helps preserve the current charge on the battery. What's not well known is how to care for the battery itself. That's just as important. Doing so allows the battery to operate efficiently. Here are a few ways to keep your lithium-ion batteries healthy.

1: Keep your batteries at room temperature

That means between 20 and 25 degrees C. The worst thing that can happen to a lithium-ion battery is to have a full charge and be subjected to elevated temperatures. So don't leave or charge your mobile device's battery in your car if it's hot out. Heat is by far the largest factor when it comes to reducing lithium-ion battery life.

2: Think about getting a high-capacity lithium-ion battery, rather than carrying a spare

Batteries deteriorate over time, whether they're being used or not. So a spare battery won't last much longer than the one in use. It's important to remember the aging characteristic when purchasing batteries. Make sure to ask for ones with the most recent manufacturing date.

3: Allow partial discharges and avoid full ones (usually)

Unlike NiCad batteries, lithium-ion batteries do not have a charge memory. That means deep-discharge cycles are not required. In fact, it's better for the battery to use partial-discharge cycles.

There is one exception. Battery experts suggest that after 30 charges, you should allow lithium-ion batteries to almost completely discharge. Continuous partial discharges create a condition called digital memory, decreasing the accuracy of the device's power gauge. So let the battery discharge to the cut-off point and then recharge. The power gauge will be recalibrated.

4: Avoid completely discharging lithium-ion batteries

If a lithium-ion battery is discharged below 2.5 volts per cell, a safety circuit built into the battery opens and the battery appears to be dead. The original charger will be of no use. Only battery analyzers with the boost function have a chance of recharging the battery.

Also, for safety reasons, do not recharge deeply discharged lithium-ion batteries if they have been stored in that condition for several months.

5: For extended storage, discharge a lithium-ion battery to about 40 percent and store it in a cool place

I've always had an extra battery for my notebook, but it would never last as long as the original battery. I know now that it's because I was storing the battery fully charged. That means oxidation of lithium-ion is at its highest rate. Storing lithium-ion batteries at 40 percent discharge and in the refrigerator (not freezer) is recommended

Final thoughts

Lithium-ion batteries are a huge improvement over previous types of batteries. Getting 500 charge/discharge cycles from a lithium-ion battery is not unheard of. Just follow the above guidelines.


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35 comments
farleyjc
farleyjc

Thank you Mr. Kassner. Ironically I just purchased a new digital camera and the manual does not say a thing about the battery except to plug in the charger. I was wondering if they had memories. 


Also, agree on the heat being batteries worst enemy. I even keep all my batteries for power tools in the house during the summer. 

atoft
atoft

Wonderful to get the right advise to get the best life on your battery. What is needed for your laptop is a program where you can adjust the level where it stop charging, and start charging. I once had a ThinkPad that came with this kind of utility. Do anybody know of a program that can do the job?

DWRandolph
DWRandolph

A little confused between #3 (partial discharge except at 30th cycle) and #4 (special analyzer required after full discharge "kills" it). I suppose "discharge to the cut-off point" could work in a notebook with functioning power monitor that is set to power off at, what, 5%? Granted that this forum is focused towards that kind of usage, but what about other equipment, or buggy gauges?

john3347
john3347

I have recently introduced myself to LI-ON batteries in hand power tools. It is disappointing that the original LI-ON batteries that come standard with these tools are a much smaller physical size than their NI-CAD cousins. This smaller size results in no more amp/hour use between charges than with the NI-CAD batteries that they replace. Larger LI-ON batteries are available for these applications at astronomical prices, making a suitable battery cost far more than the tool itself costs with the small OEM battery. The second observation is that there is no warning when the battery is going to go dead in use. If one is drilling a hole with a NI-CAD battery, the drill looses power and slows as it approaches "dead". Not so with a LI-ON; when it goes dead, it just TOTALLY quits with no warning whatsoever. It will recharge normally if recharged at this point, but can be very inconvenient in certain situations. (Perhaps this phenomenon is somehow connected with item #4 that Michael discusses in the original article.) Perhaps, as LI-ON powered electric automobiles become more popular and battery production dramatically increases, battery prices will come down.

slange
slange

How do you gauge this?

DelbertPGH
DelbertPGH

I thought I learned that the hard way, but then I did it again.

Michael Kassner
Michael Kassner

Lithium-ion batteries can last if you take care of them. Here are five tips I learned the hard way.

Snak
Snak

The high cost of Lithium batteries is due to the fact that there is only one place in the world where Lithium can be mined cost-effectively. This is in Russia - and, like other stuff we dig up, is finite. Hence I expect Lithium batteries to remain expensive. New technology required asap.

Michael Kassner
Michael Kassner

I have no experience with power tools and Lithium-ion batteries. I appreciate you sharing your experience. As for number four, I bet that is a real problem with tools. You are able to bring the battery back after a total discharge? I wonder if the device has a voltage cut-off that shuts it down before the point of no-return. That might be what you are experiencing.

Michael Kassner
Michael Kassner

The whole intent is to inform that lithium-ion batteries should not be stored fully charged. I suspect that most people would find that contrary to what they believe. Edit: Spelling

john3347
john3347

Many, I guess most, laptops have a battery charge meter built into them. (You may have to dig around in the users manual to find it on some models) Even tho they can be quite inaccurate, they can serve as a guide to a partial discharge for battery storage needs. Cell phones have a similar battery charge meter built in. Just let these battery charge meters be your guide.

Michael Kassner
Michael Kassner

I washed my son's phone once and the battery made it. Chlorine maybe?

santeewelding
santeewelding

I ever walked into a swimming pool wearing something with pockets was when I was drunk. What were you?

Realvdude
Realvdude

Don't constantly run on AC. I say maybe old tech, because perhaps charging circuits finally cut off when a full charge is reached. I have a Acer bought in 2007 that actually had a note in the package about removing the battery if running on AC for extended periods. My new Panasonic cordless phones not only have the charge cut-off, but also use two AAA sized NiMH batteries. No more $10-12 a pop for a custom battery pack. FYI - Michael, information references would be great in articles like this.

friesentech
friesentech

As it turns out, there is no shortage of lithium. Our own Karen Pease has written thoughtfully about this in the past, and today there is news that a single lithium mine in Nevada could produce enough of the stuff on its own to make 650 million Nissan LEAFs or 1 billion Chevy Volts. In reality we are likely to have a shortage of these materials dysprosium, lanthanum, neodymium, and terbium long before we run out of lithium. Just google "lithium mines" to verify this information.

john3347
john3347

"I wonder if the device has a voltage cut-off that shuts it down before the point of no-return. That might be what you are experiencing." I thought you were kinda describing a cut off point before complete battery (near zero volt) discharge in your number 4 point. The immediacy at which the drill, saw, etc. quits running suggests to me that perhaps there is a built in cut-off circuit somewhere in the battery. ??? edit: And yes, the recharge cycle appears to be completely normal, just as if the tool had still been running normally when the battery was removed for recharging.

tomjhen
tomjhen

I have the same experience with a Lithium-ion battery in a power drill. The drill simply stops and the battery recharges normally. My guess is you are right that there is a circuit in the battery pack that shuts it down before it discharges to the point of no return. The light weight of the drill is a great feature of the Lithium pack.

slange
slange

I don't have a laptop - but I do use a lot of video equipment that uses these types of batteries, and have found the built in meters to be useless - they show the batteries as fully charged right up to the point that they just quit working.

DelbertPGH
DelbertPGH

The first time was with a Motorola Razr. The battery was shot. After four days of drying out, the phone came back, though. Luckily, it happened within a week of my free upgrade, to a Palm Pre. That one fared better, but I got out within 30 seconds of exposing it, and didn't dive to the bottom, like I did with the Razr. The Palm was functioning the very next day. The don't-get-this-wet stickers on the battery and the phone both turned bright red, though. I have to wait until May to get rid of this stinking Palm. Still works, after a fashion, impaired only in its design.

Michael Kassner
Michael Kassner

I was mentioning about charging a battery in a hot environment.

Snak
Snak

and am owed at least one drink from the Aussie electronics engineer that told me that :). Thank you.

Oz_Media
Oz_Media

I have a set of 6 LiOn batteries in my mix of DeWalt and Milwaukee drills and saws. They all slow down as they near complete discharge. I find it is more apparent when in high torque conditions, such as the 1/2" drive impact gun, using long screws and running high torque on the driver etc. I haven't found the issues with them just shutting off but it may be that it is noticeable in low torque conditions where it can run on low power until finally dead. I have a half dozen batteries always rotating in chargers though, so I just pop a new one in when I can't get enough torque anymore.

Michael Kassner
Michael Kassner

I was making an assumption that there was some intelligence, whether it be the battery or device that would prevent the battery from being permanently damaged. My research was mainly with electronic devices like computers and mobile phones. That's why I was interested in what you said. Edit: Spelling

Michael Kassner
Michael Kassner

It seems that could make your work difficult at times.

Michael Kassner
Michael Kassner

It takes me back to chemistry at university. Thanks for clearing that up.

AnsuGisalas
AnsuGisalas

Conductivity is based on ionic strength not acidity or alcalicity (I forget if that's a word or not)... and water with an overall charge is really difficult to have, otherwise. Ionic strength is the concentration of ionic particles in the water. So, adding salt (Na+ & Cl-) ups the ionic strength, even though it's neutral overall.

AnsuGisalas
AnsuGisalas

Further hassles; if you put old-fashioned soap in a hard-to-rinse object, and you have hard water, then you may get deposits of calcinate soap... it's pretty much insoluble. Other problems too; you can't dissolve things easily in distilled purified water... no ions, you see. Ionic substance solubility rises as the ionic strength of the solute rises too, so if you have salt in the circuits you may have to get some ions present in the first rinses, then going towards triple-distilled water with following ones.

Michael Kassner
Michael Kassner

But wasn't sure. The dryer didn't help the hardware though.

seanferd
seanferd

And rather tends to lock up conductive ions in the water. So it probably helped.

Michael Kassner
Michael Kassner

Are very conductive. I guess the ingredients in soap are not.