Lithium batteries seem to be everywhere these days. We can find them in our cellphones, laptops, portable media players and etc. We all want to make our batteries last as long as possible, but some well intentioned advice from friends, could be harming your Lithium battery’s life span.
1. Battery Memory - When I first got my new cellphone, my friend recommended to fully drain the battery before recharging it. His reasoning was connected to the idea of battery memory. Allowing the battery to fully discharge then recharging to max, supposedly gives you the complete battery capacity. Otherwise, if you simply charged from the half way point to max battery capacity, the battery would treat the half way point as the empty point, thus cutting your battery capacity in half.
Problem is battery memory doesn’t apply to Lithium batteries, this advice was meant for Nickel based batteries. Fully discharging your Lithium battery frequently can actually be quite harmful to your battery’s health, possibly rendering it completely unusable if energy levels go too low.
The good news is today’s lithium batteries have a safety circuit in place to insure the battery doesn’t reach the point of no return. The safety circuit isn’t fool proof of course, if you leave your battery completely drained for a few days, even the circuit’s protective measures won’t save it.
2. Battery Calibrating - There is some benefits to fully discharging your lithium battery periodically, for laptops this can be especially important. If you start to notice your battery meter is becoming more and more inaccurate, it may be time for some battery calibration. By allowing your lithium battery to fully drain, this will help the battery recalibrate allowing for more accurate measurements of battery life. This should be done once every 30 charges or when you notice battery readings are off.
3. Consequences of Heat - Another enemy of Lithium battery life is heat. If you were to leave your laptop plugged in and running for a year, you should expect the lithium battery capacity to be anywhere between 60% to 80% of it’s original max capacity. This is why people that use their laptops as desktop replacements will notice greatly reduced battery life performance after one year of use. This issue can be resolved by removing the battery while using a corded power source. Now you may want to check with your manufacturer ahead of time to check for safety concerns, some manufacturers have mentioned problems such as moisture and dust collecting in the battery casing.
4. Battery Storage - If you plan on not using the Lithium battery for prolonged periods of time, then you’ll want to have the charge level at 40% and place the battery in the fridge (not freezer). Storing the battery at 100% charge level applies unnecessary stress and can cause internal corrosion. On the other hand, if the charge is too low, the battery can become permanently unusable, due to battery self discharge. This is why manufacturers recommend storing your Lithium battery at 40% charge, rather than either extreme.
Quick Overview
- Try to avoid frequent full discharging of the Lithium battery.
- For lithium battery meter calibration, periodically do a full battery discharge, every 30 charges, to increase meter accuracy.
- Avoid heat, heat is the Lithium battery’s enemy, the temperature in a car can easily rise 50F in a single hour, in some cases reaching 140F.
- If you plan to place your lithium battery in storage, be sure to have the charge at 40% and stored in the fridge (not freezer) for maximum battery longevity.
For additional information concerning batteries in general, I strongly recommend visiting Battery University.
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Filed under: Tips
18 Comments
How does this apply to the Sony Mylo, if it does have a litium battery, and IM battery is seven hours?
Arun,
I believe all but one of the guidelines I listed above should apply to the Sony mylo, the one tip that may not apply is the battery meter calibrating, which I cannot confirm.
I am looking for some guidance on failure charastics of Lithium Batterie (Non rechargable).
My application - Mamory Backup.
Nominal Voltage - 3.85 V
Equipment can work well till 2.8 V
Equipment monitors and generates ‘Lo Volt’ alarm (set point is user adjusteble).
I would like to set ‘Lo Volt’ at 3.0 volts to allow mw ~ 3 months to get around to replace the battery in the equipment.
Thanks.
dpp
Can a lithium battery be substituted for external power source on a ventilator (respirator) which typically uses lead/acid battery for power? If so, how do I adapt it?
Karen,
I’m sure it’s possible to use a lithium battery as an external power source on a ventilator. From what I’ve read about the medical industry they are slowly making a shift to Lithium based batteries. I’d like to give you some recommendations, but I don’t feel that I have enough knowledge in this area to make a sound statement.
Just a few thoughts I have on the subject. Lithium batteries stand out compared to other batteries for two main reasons, high energy density and light weight. So a Lithium battery can be the same size as other batteries yet hold more energy and weigh less. Now those two advantages would be great for portable devices, but for stationary devices where space and weight is not a big issue, it’s hard for me to justify making a switch from lead/acid battery to a lithium one.
Mr. Paranjpe
I really don’t know much about lithium battery failure characteristics besides the aforementioned ones in the guide.
Perhaps you could be more specific about failure characteristics by asking a specific question, I may be able to help.
Cook, thank you for your wonderful hands-on articles.
To the Li-battery issue, I could add that Li-batteries need NOT be charged “to the brim” every time - one of the failure mechanisms is heat as you mentioned and heat can be achieved by overcharging the battery, with a poor charger that puts out more than the usual 2,45 volts (NB: not same for every brand and chemistry).
Therefore, it is OK to stop charging lithium batteries before 100% full - lead acid batteries need a full charge to live a happy life but lithiums don’t. Lithiums are good for opportunity charging, plug-in for few minutes to get some additional mileage.
Also, like other batteries, lithiums deliver most energy over their lifetime when discharged only to 35-50% DOD (depth of discharge) from full. Typically, 80% DOD (20% remaining charge) regularly, before recharge, gives about 500-800 cycles. DOD of 35% (65% remaining) may give 2000 charge/recharge cycles or more.
Pekka,
Thanks for the compliment! The DOD part of your tips was very interesting to me, definitely a great tip to get the best bang for your buck on lithium batteries. Thanks for taking the time to share with us those additional lithium battery tips!
“full proof” should be “fool proof”.
“full proof”?
Don’t you mean “foolproof”?
The spelling error was corrected. Thanks for pointing that out guys, good catch 8).
Thanks for these tips. I’ve changed my third battery last month.
A few months back I paid a good $60 for a nice electric shaver, I was under the impression that I was suppose to fully drain the battery before recharging to get the full capacity of the electric shaver battery. I forgot to recharge the shaver one night after it had been fully drained of energy, and the next day, to my horror, it was dead… $60 down the drain, because I didn’t know how to take care of my battery correctly. After I did some more research I found out the electric shaver was running on a lithium battery and that explained why the battery wouldn’t function after being fully drained.
I thought I’d make myself useful and spread the word so others won’t have to waste money like I did 8(. I’m glad you enjoyed the guide Bura, take care!
These are useful tips, thank you.
I’d like to share with you some of my experiences with lithium batteries (I usually break all the rules with them every day…).
Laptop 1 (compaq), used as desktop replacement for 3 years. 2 completely destroyed batteries in the first two years.
Laptop 2 (acer with 17″ monitor), Always on, beside my desktop for the last 1 1/2 years. Today, the battery keeps the laptop running for 3 hours (same as new).
Digital camera (sony), after a year of inactivity the battery can keep the camera alive for 5 minutes…
Mobile Phone (ericsson with li-po battery), after 4 full years of use the battery lasted for 4 typical days (7 when it was new). After a year and a half in a drawer it was recharged again and now it lasted about 2 days (+ about 40 minutes of speaking). Not bad for a 5 1/2 year battery.
So I cannot fully agree nor disagree about the importance of following the rules. Some batteries require it, others don’t care. I believe it is a matter of hi or low quality batteries and hi or low quality rechargers.
Will overcharge affect the battery life?
I’m currently using Sony Digital Camera.
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