BU-702: How to Store Batteries

Learn about storage temperatures and state-of-charge conditions.

The recommended storage temperature for most batteries is 15°C (59°F); the extreme allowable temperature is –40°C to 50°C (–40°C to 122°F) for most chemistries. While lead acid must always be kept at full charge during storage, nickel- and lithium-based chemistries should be stored at around a 40 percent state-of-charge (SoC). This minimizes age-related capacity loss while keeping the battery operational and allowing for some self-discharge.

Nickel-based batteries can be stored in a fully discharged state with no apparent side effect, and Li-ion cannot dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. (See BU-802b: Elevated Self-discharge.) If recharged, the cells might become unstable, causing excessive heat or showing other anomalies. Li-ion batteries that have been under stress may function normally but are more sensitive to mechanical abuse. The liability for a failed battery goes to the manufacturer when a fault could have been caused by improper use and handling.

Finding the exact 40–50 percent SoC level to store Li-ion is not all that important. At 40 percent charge, most Li-ion has an OCV of 3.82V/cell measured at room temperature. To get the correct reading after a charge or discharge, rest the battery for 90 minutes before taking the reading. If this is not practical, overshoot the discharge voltage by 50mV or go 50mV higher on charge. This means discharging to 3.77V/cell or charging to 3.87V/cell at a C-rate of 1C or less. The rubber band effect will settle the voltage at roughly 3.82V. Figure 1 shows the typical discharge voltage of a Li-ion battery.

Discharge OCV

Figure 1: Discharge voltage as a function of state-of-chargeBattery SoC is reflected in OCV. Lithium manganese oxide reads 3.82V at 40% SoC (25°C), and about 3.70V at 30% (shipping requirement). Temperature and previous charge and discharge activities affect the reading. Allow the battery to rest for 90 minutes before taking the reading.

Measuring SoC is especially difficult on nickel-based batteries. A flat discharge curve, agitation after charge and discharge and temperature affects the voltage. The charge level for storage is not critical for this chemistry, so simply apply some charge if the battery is empty and store it in a cool and dry place. With some charge, priming should be quicker than if stored in a totally discharged state.

Storage induces two forms of losses: Self-discharge that can be refilled with charging before use, and non-recoverable losses that permanently lower the capacity. Table 2 illustrates the remaining capacities of lithium- and nickel-based batteries after one year of storage at various temperatures. Li-ion has higher losses if stored fully charged rather than at a SoC of 40 percent. (See BU-808: How to Prolong Lithium-based Batteries to study capacity loss in Li-ion.)


Lead acid

at full charge


at any charge

Lithium-ion (Li-cobalt)

40% charge

100% charge








(after 6 months)












(after 3 months)

Table 2: Estimated recoverable capacity when storing a battery for one year. Elevated temperature hastens permanent capacity loss. Depending on battery type, lithium-ion is also sensitive to charge levels.

Batteries are often exposed to unfavorable temperatures, and leaving a mobile phone or camera on the dashboard of a car or in the hot sun are such examples. Laptops get warm when in use and this increases the battery temperature. Sitting at full charge while being plugged into the mains contributes to a relatively short battery life. Elevated temperature also stresses lead- and nickel-based batteries. (See BU-808: How to Prolong Lithium-based Batteries.)

Nickel-metal-hydride can be stored for 3–5 years. The capacity drop that occurs during storage is partially reversible with priming. Nickel-cadmium stores well. The US Air Force was able to deploy NiCd batteries that had been in storage for 5 years with good recovered capacities after priming. It is believed that priming becomes necessary if the voltage drops below 1V/cell. Primary alkaline and lithium batteries can be stored for up to 10 years with only moderate capacity loss.

You can store a sealed lead acid battery for up to 2 years. Since all batteries gradually self-discharge over time, it is important to check the voltage and/or specific gravity, and then apply a charge when the battery falls to 70 percent state-of-charge, which reflects 2.07V/cell open circuit or 12.42V for a 12V pack. (The specific gravity at 70 percent charge is roughly 1.218.) Lead acid batteries may have different readings, and it is best to check the manufacturer’s instruction manual. Some battery manufacturer may further let a lead acid to drop to 60 percent before recharge. Low charge induces sulfation, an oxidation layer on the negative plate that inhibits current flow. Topping charge and/or cycling may restore some of the capacity losses in the early stages of sulfation. (See BU-804b: Sulfation and How to Prevent it.)

Sulfation may prevent charging small sealed lead acid cells, such as the Cyclone by Hawker, after prolonged storage. These batteries can often be reactivated by applying an elevated voltage. At first, the cell voltage under charge may go up to 5V and draw very little current. Within 2 hours or so, the charging current converts the large sulfate crystals into active material, the cell resistance drops and the charge voltage gradually normalizes. At between 2.10V and 2.40V the cell is able to accept a normal charge. To prevent damage, set the current limit to a very low level. Do not attempt to perform this service if the power supply does not have current limiting. (See BU-405: Charging with a Power Supply.)

Alkaline batteries are easy to store. For best results, keep the cells at cool room temperature and at a relative humidity of about 50 percent. Do not freeze alkaline cells, or any battery, as this may change the molecular structure.


Simple Guidelines for Storing Batteries


When charging an SLA with over-voltage, current limiting must be applied to protect the battery. Always set the current limit to the lowest practical setting and observe the battery voltage and temperature during charge. In case of rupture, leaking electrolyte or any other cause of exposure to the electrolyte, flush with water immediately. If eye exposure occurs, flush with water for 15 minutes and consult a physician immediately.
Wear approved gloves when touching electrolyte, lead and cadmium. On exposure to skin, flush with water immediately.

Last Updated: 2017-04-04

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On January 11, 2011 at 9:27am
Alexander wrote:

How many times can I recharge a lithium-ion battery? I have Sansa e200 player with the lithium-ion rechargeable battery.

On February 2, 2011 at 5:47pm
Good Idea Guys wrote:

Need to Store Batteries?  Here’s how to do it safely:

1) Keep batteries in original packaging when possible.

2) Do not store new and used batteries together.

3) If a battery feels warm, it should be discarded.

Check here for 6 more battery storage tips:


On March 5, 2011 at 3:37pm
Mark wrote:

I just started to store my Panasonic cordless drill batteries in the fridge in a food preservation vacuum bag to keep the moister out. Working ok so far??

On March 7, 2011 at 7:18pm
Bel Plews wrote:

> Never leave a nickel-based battery sitting on a charger for more than a few days.
> Prolonged trickle charge causes crystalline formation (memory).

Does this account for chargers that monitor health of the battery and apply charge when necessary?

On March 21, 2011 at 9:28pm
Matt R wrote:

One of the things that is misleading about the chart is that the voltages aren’t specified.  For example some Lithium Ion devices like my older laptop define 0% on its 6 cell as being 10.8V as opposed to a very small amount on some newer laptops.  Similar to that of my PSP where “100%” encompasses slightly above 4 volts to 4.2.  If I were to make a guess it would probably be because of USB charging is painfully slower at higher voltages.

The other is that some batteries protective circuits and other miscellaneous electronics slightly drain the battery.  Some Lithium Polymer batteries exhibit zero discharge at all.  I have an old Motorola cell phone that I haven’t charged for a few years and every once in a while I’ll turn it on and it’ll show one out of three bars…Just the way I left it.

To keep it short, assuming that 100% is 4.2V it would be theoretically impossible to hold the average device battery up there.  There are some exceptions to this but the best bet to storing them is to monitor the device’s progress every few weeks and go from there.

It would be nice to see some more info on that chart.  Especially in contrast on single cell versus multiple cell packs.

On March 25, 2011 at 4:45pm
Ty wrote:

If you’re going to be storing a rechargeable battery, store it at the 40 percent state-of-charge (SoC), and then recharge / discharge back to the 40 percent state-of-charge (SoC) every month to keep the internal batteries in good condition. Store batteries just below room temperature, more specifically at 59°F.

On June 27, 2011 at 8:08am
tom wrote:

Would storing a Li-Ion battery at 40% charge in a freezer at -18 C prolong the life more than storing it in a fridge at 5 C ?

Is it possible to store a Li-Ion at a temperature cold enough to damage it (say -25 C)? Will crystals form in the chemistry that could cause damage or a short?

Any specific concerns about condensation effects when taking a battery out of the fridge/freezer and plugging it immediately into your laptop for 1 hour of gaming (on batt power only)?

Thanks for the info! Great site!

On October 12, 2011 at 10:17pm
kitk wrote:

There used to be a procedure to drain a charged lead-acid battery, for long term storage; in effect, making it a dry-charged battery. Does anyone still living remember what that was?

On November 4, 2011 at 6:46am
Bernard Rieck wrote:

Where would be a good place to store a dead lead acid battery until they can be dispode of properly.

On November 26, 2011 at 2:25pm
Aleks wrote:

What would be better for a saving of a Lithium Ion battery: to be in every day working laptop using external power or in a fridge?

On December 7, 2011 at 8:03am
NormMonkey wrote:

@Aleks For a laptop Li-Ion battery, well, the battery would be better off in the fridge at around 40% charge.

Keep in mind that you won’t be able to use Suspend-To-Ram without a battery attached.

Many laptops allow you to set them so they don’t charge to 100% while attached.  Keeping your battery in your laptop but at 40% charge rather than 100% will prolong its life.

My battery temperature is around 30 degrees Celsius while sitting attached to my laptop on AC power neither charging nor discharging.

On December 9, 2011 at 2:01pm
Guillaume wrote:

Not sure the fridge is a great idea. Don’t forget that temperature is not the only storage criteria. High humidity environnement may affect the battery life expectancy !

On December 10, 2011 at 3:02am
Aleks wrote:

@Guillaume Thanks. Do you have better idea? If the battery is in a plastic bag?

On December 12, 2011 at 6:23am
Guillaume wrote:

Optimal storage conditions are :

Clean and dry location
Temperature below 25°C (10°C would be optimal if you want my opinion)

I dont know about your location. In my case, winter is cold (-10°C average) so I use the garage for battery storage. My garage is heated at 12°C so the humidity level is low and the temperature is good.

Keeping the battery on the laptop at 40% charge as suggest by NormMonkey could work but dont forget that the heat coming from the laptop will affect the battery so you may want to store it somewhere else.

For the bag idea, it may help to prevent dirt and other stuff to be in contact with the battery but I dont know about humidity. You might want to use the basement as it usually colder there.

On December 12, 2011 at 1:16pm
kitk wrote:

I take it that no one watching here has ever heard of dry charged batteries. If that changes, please let me know.

On December 15, 2011 at 7:19am
John Fetter wrote:

Storing a fully charged lead-acid battery at -10 degrees C is absolutely perfect. The acid will not freeze. You can go down to - 20 but don’t go too far down. Self discharge is a chemical process. It speeds up with increase in temperature, slows down with decrease. It is not linear. Lowering temp. dramatically reduces self discharge. 

Dry charged batteries were made decades ago when the industry had difficulty keeping the self discharge of batteries down. Simply charge to 100%, drain out all the acid, wash out residual acid, dry. Then seal the vents air tight. The negatives will discharge spontaneously in contact with air. When the battery is needed, refill with acid, charge. Very cumbersome. Easier to put the battery in the fridge!

On December 25, 2011 at 6:07pm
Luffy wrote:

‘Avoid freezing. Batteries freeze more easily if in discharged state.’
Do you really mean: Avoid freezing.Batteries discharge more easily if in freezed state.

On December 26, 2011 at 10:20pm
kitk wrote:

Quite right, and thank you for your advice on dry charged lead-acids. I am among those burdened with a desire to know how and why things work, much to the amusement and consternation of the bulk of the populace. There are not enough of us to go around, so at least the net allows us to offer what we know.
Thank you again.

On January 7, 2012 at 5:35pm
ritch wrote:

how long can you store AA and AAA if you have a lot of new ones

On January 12, 2012 at 4:12am
John Fetter wrote:

Ritch, Put your AA and AAA batteries in your fridge and they will stay fresh longer than storing them any other way. Some of mine have been there for more than 3 years and they come out working fine. The colder, the better but do not freeze.

On February 16, 2012 at 1:33am
Viktor Berglund wrote:

I’m writing a guide regarding the computer’s battery. Can sleep mode damage the battery capacity in a lithium-ion battery.

On February 21, 2012 at 1:20pm
Thom wrote:

When I bought a used laptop I automatically bought a new 9-cell replacement battery for it.  When my laptop arrived, I discovered that the battery that came with it was basically new and also 9-cell.  I’ve opened both batteries so I shan’t sell one.  Is it better to store one of them at 40% charge to wait for the other to go bad, or should I rotate them once a month, always storing the other at 40% and trying not to let the charge drop below 40%?

On February 21, 2012 at 3:10pm
Matt wrote:

Thom.  What kind of laptop do you have?

On February 22, 2012 at 10:25am
Thom wrote:

It’s a Thinkpad T60.  It dual boots Ubuntu 11.10 and WindowsXP, but I mainly use it for Ubuntu (I notice the predicted battery life is strangely longer under XP though).

On February 22, 2012 at 10:27am
Thom wrote:

It’s a Thinkpad T60 that dual boots Ubuntu 11.10 and WindowsXP (I use it mainly for Ubuntu but I notice a much longer predicted battery life under XP strangely).

On February 22, 2012 at 2:41pm
Matt wrote:

I would guess that, but that’s only because I use a T60 and an X31.  As for the two 9 cells what I would do is check the Power Manager and note the manufacture and the total capacity (you can check the total capacity in Ubuntu also).  Panasonic batteries in my experience tend to hold better over time because of their better construction and their microcomputer doesn’t crap out like the Sanyo’s (my 9 cell is a Sanyo and my 6 cell is a Panasonic.  So far the Panasonic seems to be more consistent and autocorrecting than the Sanyo).

It’s not too strange under XP.  If you have the ATI chipset (X1300, X1400.  Not sure the T60 has the CAD one) the power management features are enabled with the drivers.  The Ethernet drivers are also programmed to disable the interface if not in use (not sure about Ubuntu).  Your best bet is to check Thinkwiki for tips on it but not sure if it covers Ubuntu 11.1

On February 22, 2012 at 3:13pm
Thom wrote:

Right now I have the replacement in which it says is a Sony at 95.7% Capacity.  The battery that came with it is at home and is the original Lenovo/IBM.  When this computer came in the mail it was *spotless* and looked brand new (except the windows XP sticker on the keyboard is partly rubbed off).  I got quite lucky.  There wasn’t even any wear on the touchpad or keyboard, these all had the slight matte finish found on new devices.  It was supposed to have been used in a professionally capacity before it was resold by the computer shop in MA.
I installed PowerTop this morning but I’m only half sure that I’m using it correctly.  I was going to fool around with CPU Frequency Scaling Monitor but wasn’t sure if that would make a difference.  I saw something about installing proprietary drivers for the GPU.  I’m not sure how to verify but I *think* that it uses the ‘Intel Graphics Media Accelerator 950 Graphics Card’.  This is based on looking up the Product ID: 195143U.

On February 22, 2012 at 3:54pm
Matt wrote:

Yeah, the Type 1951 has the GMA945 or something like that.  As for the Sony battery I’d urge to make sure it’s not a part of the recall (if the battery was manufactured recently it should be OK).  As for the quality I do not know.  I’ve read they’re really bad but I don’t use them so I wouldn’t know.  Finish wise mine was like that but the motherboard failed 3 months into ownership.  However the keyboard, palmrest and the bezel can be removed with 9 screws and only about 5 minutes so it as skeptical as I am it could of been easily replaced.

On the Windows side most of the settings you’d want to mess around with would be in the Lenovo Power Manager or the ThinkPad Configuration Utility.  They allow for fan control as well as other controls including the optical drive speed.

On February 25, 2012 at 10:20am
HTWingNut wrote:

This information is confusing and misleading regarding the storage of batteries. I have never had any laptop Li-Ion batteries degrade 20% over the course of a year even if left installed with laptop connected to AC 100% of the time. Wondering what conditions these were tested under and how old the data is?

On February 28, 2012 at 3:58am
Peter wrote:

Can the Lifepo4 batteries can mount in any position during usage. Or any restriction of keeping it vertical as the leads always upwards.

On March 28, 2012 at 2:19am
Mark Smith wrote:

The Li-Ion battery should be good for up to 500 cycles before it starts to lose its capacity, depending on its brand and quality.

On April 12, 2012 at 7:42am
AnthonyJosephWeber wrote:

need batteries for experiments

On July 11, 2012 at 1:11pm
ramon leigh wrote:

Just some of the many reasons we need much better batteries than the crappy ones we have today.

On July 13, 2012 at 8:52am
John Fetter wrote:

Ramon - The problem is caused mainly by the people who are buying the batteries !
(1) Nowadays most people insist on buying the cheapest battery they can find to replace the one that has just worn out. Getting something at the lowest possible price apparently makes them feel clever.
(2) The cheapest batteries can only be produced by manufacturers who are willing to cut corners.
(3) Manufacturers who refuse to cut corners go out of business.
(4) The system is self perpetuating, until all the batteries on the market are junk.

On July 18, 2012 at 6:16pm
Martin wrote:

urgent…..Please help finding the answer.asap
What is the correct answer for the condition of a stored lead-acid batter does’nt full charged .Why?
a) the lead plates have crystallized
b) The lead plaes have ionized
c) the specific gravity of each cell is high
d) the voltage of each cell after chaging at its normal rate is low

Thank you very much.

On July 18, 2012 at 11:51pm
John Fetter wrote:

Martin - If your lead-acid battery has been stored for a very long time, the plates will most likely have become sulfated. That is not good. A sulfated battery refuses to accept a normal charge. There are many different types of products on the market described by their manufacturers as desulfators. Take your pick.

I stored a lead-acid battery for five years without it becoming sulfated by using the following procedure:
1. Remove caps. Empty out all the acid and store it separately.
2. Flush out the battery cells two/three times with reasonably pure water, (can use drinking water), to remove most of the acid.
3. Fill cells to the maximum with water.
4. Replace caps. Put into storage.
5. When the battery is needed, empty out the water.
6. Fill the cells with the acid that you stored separately.
7. Charge the battery.
The battery will accept charge and give virtually 100% of the capacity that it had on the day when you put it in storage. The plates will not be sulfated. The plates will not be buckled. I presume this method can preserve lead-acid batteries in storage for decades.

On August 21, 2012 at 2:19pm
Kevin wrote:

I have lead acid batteries that I use on different instruments. Initially they work fine; However, when they deplete they fail to recharge again. The batteries were inspected and they do not suffer from sulfation. The batteries were stored for 4-5 months in room temperatures. What would the problem be?

On August 21, 2012 at 2:48pm
John Fetter wrote:

Kevin - You appear to be saying that your batteries were not fully charged when you stored them. Modern lead-calcium alloy grid batteries can develop what is known in the trade as “open circuit” when left like this. Without knowing what type of lead-acid technology, I am guessing. Might be possible to correct.

On November 1, 2012 at 12:15pm
Judy wrote:

I was told that an easy way to keep seldom used D batteries in a 2 cell flashlight from discharging over time was to put the end one in backwards, so that the batteries negative ends are together instead of positive to negative.  Good advice?

On November 1, 2012 at 4:09pm
John Fetter wrote:

Judy - It makes no sense to connect them back to back. I made a suggestion on Jan 12 - simply put them in the fridge. Low temperature reduces the rate of chemical reactions inside the batteries, hence reduces self discharge.
On another subject. If you want to keep a tube of superglue fresh, put it in the fridge.
It is amazing how useful fridges can be.

On November 3, 2012 at 2:19pm
Judy wrote:

Thanks for the fridge suggestion, John. but I think the idea about connecting them back to back is that both batteries would be in the flashlight.  The fridge is no doubt a good idea for a flashlight in the house but what about a flashlight kept in the car, the boat, and in other places where the fridge isn’t handy. And my main concern is, first, will connecting them back to back actually reduce self discharge and secondly, is it safe?  Does back to back connection increase or decrease the chance of corrosion…or is there no effect at all?

On November 3, 2012 at 5:38pm
John Fetter wrote:

Judy - When flashlights are in the car, the boat and in other places and are not being used, I would naturally expect they would be switched off. Off is off. So why mess with the batteries? Someone else wants to use the flashlight in an emergency - not unusual - and finds it does not work. There is no technical, no practical merit.

On November 7, 2012 at 10:28am
Judy wrote:

Does the back to back connection of the batteries decrease either the self-discharge or the chance of corrosion?  That;s the issue in my question. Is anyone able to address this question?

On November 7, 2012 at 12:47pm
John Fetter wrote:

Judy - It has no effect. Zero. It is a complete waste of time and effort. Probably started as one of those urban legends.

On November 18, 2012 at 4:22pm
Craig wrote:

We live in a very cold winter climate and remove 12v deep cycle batt’s from boats/campers and store in garage until spring (6 mos). How should batt’s be stored and maintained? Should batt’s be stored fully charged? Should a low amp batt charger be used to maintain a constant state?

On November 18, 2012 at 5:31pm
John Fetter wrote:

Craig - ALWAYS store lead-acid at full state of charge. They do not mind the cold although do not let them go much below -10 degrees F. A CHARGED lead-acid battery will not freeze at -40 but will freeze below that. A partially charged battery might freeze at -40. The cold reduces self discharge, prolongs battery life. A low amp charger will keep the batteries fresh. Might be a good idea to use a timer to switch the charger on 30 minutes per day only, to make sure there is no water loss.

On November 18, 2012 at 5:56pm
Craig wrote:

Thanks John. Any worries with gas vapors from charging batteries in the garage?

On November 18, 2012 at 10:52pm
John Fetter wrote:

Craig - None. You would hardly be charging the battery - merely keeping it in good condition.

On December 15, 2012 at 6:44am
Karan wrote:

Thanks for the info.
I am using my laptop battery from last one year. But now i started using laptop like desktop.So is it beneficial to store battery now.?

On January 4, 2013 at 1:17pm
T. Harrison wrote:

I have dozens of cr2032 3-volt lithium batteroes used in votive lights at Christmas. Now I want to store them until I want to use them again. How do I safely store these batteries?
Can they stack? Should there be paper between them? Should they go in the fridge in a sealed plastic bag? Should they not touch each other?

On April 16, 2013 at 12:35am
Freddie wrote:

Whats the best way for getting as much health out of your battery: Using the computer at 100% or disconnecting it and using a cycle?

On August 3, 2013 at 2:50pm
Nader Bourham wrote:

Does putting batteries in a calculator and not using it waste battery?

On August 24, 2013 at 9:15am
Stanley Kaplan wrote:

Best way to vharge NiCad batteries fir battery oowered tools and best way to charge Litham Ion for same tools Also, best way to store the above for severa months ;lrior tous ans store again Thenk You.

On October 3, 2013 at 12:24am
Maria wrote:


I want to know what is the ideal Temperature for Li-Ion Batteries transportation (by plane)

On October 3, 2013 at 9:35am
Stanley Kaplan wrote:

Can you please tel me what the best procedure is to charge an 18 volt NiCad power tool
Battery so as not to retain a memory and have the longest life. I use the battery for about on and off at one lalf hour and then charge. I have been told to take the battery , use it regardless of no particular time and when it just about the time when the drill slows down, charge it with the factory battery charger.  ?  Thank you.

On October 5, 2013 at 12:37am
Dinh wrote:

What happen if we store a Lead acid battery which not yet filled acid for a long time?

On October 5, 2013 at 3:31am
John Fetter wrote:

Dinh - I assume you mean lead-acid that has come off the assembly line, never been filled with acid, also known as unformed. I recently used batteries that came off the assembly line in 2002, were kept in storage all this time, filled them, formed them and they worked just fine.

On October 8, 2013 at 3:38am
Dinh wrote:

Thanks Jonh. But I think that is impossible for using a battery stored in 10 years. Did you mean 2002 or 2012? Now I have problem with some batteries produced in 2008 and can not use. I’m trying to know what happened with the plates and the separators.

Thanks for your reply.

On October 11, 2013 at 2:36am
Rolv wrote:

We use Leica Li-Ion battery GEB221 7,4V 4,4Ah
Up till today batteriers were always put in the charger after use and remained there till next time (trickle charger from Leica).For some reason it has deen decided to keep the batteries out of the charger after and between use (some will put a battery showing low capacity into the charger after use and remove when fully charged).
The question is how to ensure that going for work with our total station and always pick a battery with 90%-100% capacity.
Or put it in another way. How much does a battery of this type self-discharge epr week?

On October 13, 2013 at 10:20pm
Matt R wrote:

Rolv, the best way to gauge self discharge is to monitor the battery.  If the cells are unprotected they will never undergo a self discharge.  Most of the time, if not all of the time the circuit board that prevents the battery from going into an unsafe overdischarge varies on the make and model.

I’ve seen some that will never lose a drop after a year while I’ve seen many that’ll go to 0% in a week.

On November 14, 2013 at 4:29pm
gav wrote:

does it effect a car battery if it is store on conrete more so than wood

On November 14, 2013 at 4:58pm
John Fetter wrote:

gav - Absolutely not. There are many lead-acid battery myths and this is one of the silliest.

On November 24, 2013 at 1:40pm
Jacques Charpié wrote:

I have an Bionx electric bike with a Li-Mn battery.

Is it a problem to let this kind of battery on the cold at the office (maybe 0°C, -10°C or lower) during a couple of hours every day? Show I remove the battery and put it inside everyday?

The battery is never at let at low capacity

Thank you

On January 20, 2014 at 10:46am
Judith wrote:

I just watched this video and it is an eye opener about storing batteries.


On January 28, 2014 at 10:54pm
konings wrote:

can you store lead-acid 2V deep cycle (OPzS) batteries in sea containers (ambient temperature above 40 degr C)? The batteries are new and pre-charged.

On January 30, 2014 at 1:55am
John Fetter wrote:

konings - Bad idea. Too hot.

On January 30, 2014 at 4:48am
konings wrote:

Hi John, that’s what I thought. If the batteries have been stored for 5-6 months in those conditions and after filling with acid the SG level is low (1,160 -1,190) and V between 1.82 and 1.94V - would it be possible to recover them?

On March 14, 2014 at 8:59pm
Gary wrote:

I have an AAS in power generation, and I graduated with a 3.93 GPA and this garble is down right confusing. What say you compile one easy to understand section, instead of letting anyone who thinks they know it all to verbally puke on your site. Don’t get me wrong, many of these people may really know whats up, but who has time to read all this crap, then do research to see what is correct and what is truly crap? Too much, yet too little!

On June 3, 2014 at 11:54am
Jack wrote:

I’m a complete ignoramus in this area but I’ve a query I’d appreciate an answer to. I believe standard rechargeable batteries - AA, AAA, C and D etc -  come to you all but ‘dead’. They need charging. The pre-charged ‘Eneloop’ types obviously do not. If that is so wouldn’t it make more sense for the purposes of long-term storage - and I do mean long-term, like a decade or so - to buy standard rechargeables [whether nickel-cadmium or the newer nickel-hydride] over the more expensive pre-charged simply because the standard variety has nothing to discharge and as such cannot be damaged by being allowed to run down excessively while packed away in the cupboard/cellar/garage/ attic? Thanks for any advice.

On July 20, 2014 at 6:01am
Patti wrote:

I have a drawer full of batteries… AAA’s, AA’s, 9 volts, watch batteries, etc. Some brand new, still in the packaging. Went to put new batteries in the remote and discovered all the batteries are dead. I used two of them last week for another remote and they seemed fine. What could have happened?

On August 13, 2014 at 2:01am
shah sawar wrote:

my ups two parallel battries is going on since two mnths now I want to store it for one year I have a ups charger and 135 watt battries is one each
so gonna halp me
mine battry is acid water battries

On September 2, 2014 at 12:27pm
Eterick Stonely wrote:

What are the sources to this article? I have found research articles that disagree with this statement, and state that the batteries should be stored at much higher voltages. While I do not disagree with this webpage, I would like to see where the information was drawn, to come to my own conclusion of which claim I should follow.

On September 2, 2014 at 5:01pm
John Fetter wrote:

Eterick - I am curious how you envisage storing batteries at much higher voltages than the voltages they naturally develop on their own accord while in storage.

On October 30, 2014 at 9:22am
Sebastien Grolleau wrote:

Same comment as Eterick Sonely. This article is very interesting but it would be interesting to include sources for your article. Where does the figure of 40% for “optimal storage mode” for lithium-ion come from ? Is it the same for all lihtium-ion chemistry ? Does it rely on on a scientific and rigorous study ?

On November 7, 2014 at 10:34am
ruben wrote:

I have to buy a li-Ion cell for my laptop. The seller is offering a cell with manufature date 10/10/2011 !
Can I buy or not?

On February 2, 2015 at 7:14am
robert dowling wrote:

need advice on a 12 battery.my project is to walk solo across a salt desert in Bolivier .The day time temp 21-25 deg c,night time drop to 10 -15 below.I need battery to power charge my video camera battery on the cig attachment.Camera 7.2 v my solar panel is max 12 W output to drip charge 12v battery during my walk.I have 12 hours of light per day and 75% sun light.this is a 6 week trip.
would it be best to get a dry cell or wet cell battery heavy duty.
I will have to purchase battery in the country ref airway cargo restrictions so may be limited to quality.if this is not possiable to pull the battery in my cart on a harness with other stuff can i bury ( a cache ) on key points along my route ! would a battery retain charge 3 weeks buried and covered up ?? any advice would be fab

On March 9, 2015 at 8:48am
B. L. Kruisceal wrote:

I have a phone with a sealed in battery.  Is it ok in the fridge?  which shelf should I use?  I suppose I should keep it away from the vegetables or high humidity.  Any other secrets?

On March 18, 2015 at 10:13am
Advo wrote:

The 40% SOC value is a compromise - li-ion batteries age even less at 0% SOC, but you don’t want the battery to go so low that it goes into sleep mode and is dead.
For purposes of ageing, however, 0% SOC is better than 40%.

On April 13, 2015 at 11:32am
Aaron wrote:

Can you update this to include alkaline batteries in the table?  I know they are not rechargeable, but proper instructions and temperatures for storing them would be useful, as they can degrade and leak if not stored properly.

On April 13, 2015 at 4:33pm
John Fetter wrote:

Aaron - I have recharged the same set of alkaline batteries in my flashlight five times. Recharging works with some brands, not with others.

On April 13, 2015 at 4:42pm
Aaron wrote:

Thanks for your reply, but whether or not they are rechargeable was not really the subject of my comment.  I only mentioned the “not rechargeable” to distance to discussion from the subject of how storage effects how well a rechargeable battery holds its charge.

The point of my comment was to suggest that storage information for alkaline batteries be included in the table.  Alkaline batteries tend to hold there charge very well, so that is usually a minor concern, but they do corrode and leak more quickly if not stored properly.

On April 13, 2015 at 5:17pm
John Fetter wrote:

Aaron - Store them in a fridge. When in use, keep them cool. The ones that don’t like being recharged reveal their “reluctance” by leaking when charged. This implies that some manufacturers do not seal their batteries very well. Conclusion: There are good ones and bad ones.

On May 13, 2015 at 12:30am
soleh wrote:

Use solar and rechargeable batteries altogether

On July 17, 2015 at 2:08pm
Larry wrote:

The advice: “Avoid freezing. Batteries freeze more easily if in discharged state.” wouldn’t this apply only to batteries with a liquid electrolyte?
What do you think about freezing fully charged Nickel based batteries?  I wouldn’t think there would be any negative affects and it would both reduce the aging process and preserve the SoC.  Correct?  Anything wrong with freezing?

On July 21, 2015 at 5:15pm
John Fetter wrote:

Larry - You know what happens when you put a plastic bottle of milk in the deepfreeze. It expands and bulges. Same happens to a battery, plus the battery elements get ripped apart. I would have thought that would have been obvious.

On July 22, 2015 at 12:19am
Larry wrote:

Water is unique in that it expands upon freezing (because it changes from an amorphous to crystalline structure). Most things contract. As I mentioned above avoiding freezing would apply to batteries with liquid electrolyte. But Ni based batteries are solid state. I don’t think exposing them to freezing temperatures would cause any damage. Additionally Table 2 on this page indicates that at 0C Ni batteries recover 99% capacity after one year of storage but much less at room temperature.

On July 22, 2015 at 1:25am
John Fetter wrote:

Larry - The electrolytes of most batteries, with exception of Li-ion, contain water. Even apparently non-liquid electrolytes. Electrolytes generally freeze at a significantly lower temperature than water. Reducing the temperature of a battery to below the freezing point of pure water will not necessarily freeze the electrolyte. If you are so certain that you can freeze your Ni based batteries, why ask and why don’t you simply go ahead and freeze them?

On August 6, 2015 at 3:06am
Robert wrote:

In case of sealed lead acid batteries storage for 6 or more years, what would be the better technical strategy, no matter the money.
- Full charge, frecuent voltage control, recharge when necessary and yearly tests
- Continuous charge, voltage control and yearly tests
- Just discard the batteries and buy new ones when needed

On August 6, 2015 at 3:37am
John Fetter wrote:

Robert - Sealed lead-acid batteries were conceptualized by marketing people, not engineers. The engineers did what they were told to do. Sealed lead-acid performance and longevity are unpredictable. Use flooded batteries with pure lead grids. Float at 2.23 V per cell.
You can, theoretically, store a FULLY charged sealed lead-acid in a deepfreeze at minus 20-30 degrees C and expect it to work after 6 years. The electrolyte of a fully charged lead-acid will not freeze.

On August 7, 2015 at 5:54am
Robert wrote:

John - Thanks for the reply.
already the batteries have been stored for 6 years, I think its time to spend a bit of money,  check their state (IEEE450 IEEE1188) and take a decision on keeping/discarding.
Enjoy the weekend

On August 7, 2015 at 7:46am
John Fetter wrote:

Robert - You are obviously well aware , of course, that batteries can be stored for as long as anyone cares to store them. The unspoken question relates to their subsequent viability. Would you like to share the details of the test results you obtained from the batteries you stored, at the conclusion of the six year period?

On August 9, 2015 at 6:04am
Marino Guerieri wrote:

It seems to me that my float charger (3-phase smart charger) is not working right. I can hear slight boiling of the electrolyte (few bubbles here and there). I’ve measured a current output of 40 mA while float charging.

Am I right about it? From what I’ve read on the internet, it seems to be that it should contribute greatly to plate corrosion from too much boiling (oxygen release) and that it’s not a good thing. I’ve decided not to keep my battery on float charger while not using it because it doesn’t seem good to me.

A side note:
I admit to using starter batteries for deep cycling, and to be honest, it works for me. Perhaps I’ll kill the batteries prematurely, but I’ve gotten them really cheap and they have been going for quite some time (like 20 deep cycles and they are still good for what I need them). Last summer I was really pulling juice out of them like crazy and they were good. But then for the last year I borrowed them to a friend and he didn’t really charge them well. And he returned them to me in a “7V state” smile
And that really damaged the battery more than deep cycling! It went from 4 hours of use to 2 hours, in the same conditions. So I’m a great believer in taking care of batteries while not using them, even if you misuse them!

My dillema is whether I should charge my batteries and store them away, or keep them on a float charger to prevent self-discharge (sulfation)?
It seems to me that float chargers may not be that well optimized and that they are inducing corrosion, as written above.

Perhaps I should keep them floating for just 24 hours or so, to be sure all soft sulfation is gone? But not indefinitely?

Please help me clarify those issues.

On August 9, 2015 at 5:31pm
Alice wrote:

The 40 mA float charge is keeping your battery charged and is not causing plate corrosion. If you don’t keep your batteries charged in this way, you will be kissing them goodbye.

On August 10, 2015 at 6:30am
John Fetter wrote:

Marino - All lead-acid batteries suffer from slow self-discharge. It is caused by inevitable impurities mixed with the lead. The reaction leads to a gentle evolution of gas. Batteries never stop gassing until they are fully discharged. You need to counterbalance the discharging by trickle charging to keep the battery alive.

On August 10, 2015 at 6:44am
Robert wrote:

John - For sure I’ll share the results.

On August 10, 2015 at 7:16am
Cricket Proctor wrote:

I have a problem and a question. All the stores around me have stopped carrying the battery I need for my camera (Lithium CRV3). Wish I knew why, but you can’t answer that I’m sure. Anyway, since no one carries them anymore, I’m having to order them online. Which means that unless I order 2-4 of them at a time, the cost can be quite high in shipping. So my question is, how do I store them? A battery usually lasts about 6-8 months in my camera since I don’t use it all that often. But everything you said and the charts above are confusing to me.

On August 10, 2015 at 7:21am
John Fetter wrote:

Cricket - Wrap them in plastic and put them in the coldest area in your fridge.

On September 8, 2015 at 1:16pm
Ramon L wrote:

Thanks for posting the article.
As for the comments, please Darwin, don’t let me down.

On November 30, 2015 at 5:29am
Amandeep Singh wrote:

What are the guideline to store batteries. like design of racks?
Can we store batteries in stack position?

On December 14, 2015 at 3:05pm
doug madril wrote:

we had a house fire and we had several boxes of energizer batteries. some seem to be ok but others don’t appear to last as long in flashlites etc. was it the fire heat that decreased life of batteries or my in the drawer storage method that minimized there life? most of them are aa, aaa, c and d with a few boxes of 1.5v hearing aide batteries types.

On February 26, 2016 at 3:10am

never let battery discharged for long time below freesing temperature

On March 30, 2016 at 9:16pm
Ken Eastman wrote:

I have a GEM golf cart with 6 12 volt lead acid batteries.  I recharge it each time I use it.  My problem is I’m in a hot climate and the cart will sit in the garage in up to 115* temps for the summer. 
The charger charges all 6 batteries and limits the charge.  I’m thinking if I could find a charger that would come on once a week for 3-4 hours things might be OK but I do worry about the acid levels.  I’m told the alternative is to remove all the batteries and let them sit. Thanks.

On April 21, 2016 at 8:13am
Anthony Davis wrote:

I have a used good function laptop battery that is 1 year old and a brand new one charged at 40%.  Question is:  should I store new one in fridge and continue using old one or visa versa?  In other words would I get more longevity in fridge out of old or new battery?  Thank you

On April 25, 2016 at 5:20am
RG wrote:

I have numerous brand new non rechargeable batteries. ( AA, AAA, C, 9 Volts; mostly Energizers). I opened the packages and have been keeping them in a kitchen drawer in a ziplock bag. Is this a fire hazard? Should I have them store them in a plastic, compartmentalized container? What is the best way to store them?

On May 18, 2016 at 3:37pm
Ian Bunten wrote:

I have a Nikon EN-EL3e Li-ion Battery for use with my camera, it has been in the camera for well over a year and when I tried to recharge it today nothing happened, it didn’t charge.

I assume that it was completely discharged and therefore dead! I don’t want to buy a new one if there is anything I can do to revive it, suggestions?

On May 18, 2016 at 8:26pm
Matt R wrote:

Ian, the only option you have is to leave it plugged in for an extended period of time just to see if the battery isn’t in a ‘deep sleep’ state.  Otherwise if it doesn’t charge there is no safe way to revive it.

If the camera can be operated without a battery it would also be useful to make sure the camera itself functions.

On July 13, 2016 at 7:36pm
JT wrote:

I sit in an office with 20-40 new 12v batteries and many times with 10-20 used 12v batteries. Also there will be about 10 Ergotron COWs (computer on wheels) with one or two batteries in each one running. Can this be harmful to my health? Assuming none are damaged. Typical office in a hospital that stays about 70 degrees about 20x20 with the door always closed.

On September 10, 2016 at 10:31pm
Afseer wrote:

While operating reachtrack machine. I feel burning smell. And then I stopes engine.  I found battery is burning with small fired. I stoped that fire. Why it’s happened ? And what is the saftey of next steps? Please advise the reason!

On September 17, 2016 at 8:26pm
Koi wrote:

What is the typical procedure for stocking wet lead acid batteries.
Do they actually recharge them when down to 70% SOC or (3x2.07) 6.21 v for a 6v battery?  I ask a guy at a larger battery store and he gave me a bewildered look when I ask about trickle charging inventory.

I just got some L16-PAC Trojans with two at 6.00 V and 4 @ 6.21 V.
I can see the 6.2 as ok and with in 6month stock at 70%soc, but the other two at 6.00 seem to be stocked maybe a year or more with no charging. 

Is this a typical problem with distribution of these items.  I am guessing even the main warehouses do not have charging capabilities since H2 build up could be an issue inside a building.

On January 22, 2017 at 7:15pm
andrew su wrote:

Can the battery (e.g lead acid, Sealed battery VLRA) be stored together with petroleum oil lubricants (POL) in the same room or building? Is there any safety in impact? Thank.

On June 8, 2017 at 12:41am
Sal wrote:

I had purchased a Lithium Ion powered hair trimmer 7 years ago and tried it and then put it away.  just pulled it out and tried to charge it.  no sign of life, charger does not get warm but reads rated output and charge light does not illuminate.

Just read: Lithium-ion must be stored in a charged state I guess it discharged and is now in sleep state??  Did I kill it by not using it??

On June 8, 2017 at 1:10pm
Matt R wrote:

@Sal.  Essentially, yes, the trimmer died because the battery was allowed to go into an overdischarged state.  You could try to leave it plugged in overnight to see if the battery is in a deep sleep but at that duration the battery is probably too flat to reliably charge.

On June 9, 2017 at 7:42pm
Sal wrote:

Thanks for your reply.

Overnight made no change.  No heat in charger so it is not drawing current.  Strange that overdischarged leaves it an open circuit . . . Are they not born with 0 charge?

Is there any way to wake it up??  Have electronics skills and some tech on hand.

On June 12, 2017 at 11:20am
Matt R wrote:

All Lithium Ion batteries for consumer user have microcontrollers managing the circuit.  When it reads 0.0V it means that the battery is disabled or in a deep sleep.  It does have some voltage, but not enough for safe use.

Considering that trying to work on that battery may cause it to explode or rupture, I would probably just replace it if it doesn’t run on AC power.

On June 15, 2017 at 9:33pm
Sal wrote:

I magically managed to open the device without destroying it.  there is a small but elaborate charging circuit that is run from a wall wart and the battery is tab soldered onto the board which is just about the size of the battery.

Is the battery in a non-recoverable charge state??
Is there a controller circuit inside the battery??

I have various test equipment about and can apply a specific electrical stimulus if it can revive it to where the charger would address it.  It appears that finding a replacement my be daunting.

So short of making this a wired device and tossing the battery altogether, Is there some magic I can use to influence the battery to attain a chargeable state??

Thanks much for your conversation!

On June 19, 2017 at 9:42am
Matt R wrote:

Without having pictures it would be hard for any of us to tell.  Push comes to shove you could take a multimeter and measure the voltage of the battery while it is still attached to the board (assuming it’s soldered on and can’t be unplugged) and if it’s 0.00V more than likely it has a protection circuit though do not assume for it to be the case.  The only way to truly know would be to remove any sort of wrapping the battery would have but even then it might not have any.

Fortunately, Lithium Polymer (assuming it’s a pouch and not hard cells) comes in a variety of different sizes.  As long as it has a similar capacity and size it does not need to be exact but should be within a 5-10% variance of the device’s capacity.  At least, that’s how I would do it.

On June 20, 2017 at 12:57am
Sal wrote:

Will meter it and then unsolder it from the board to see if the markings can give me an idea of it’s origin/nature.  6 years old so there is a possibility.  Will send you a picture as soon as I have time.

Maybe tickling it with some dc waveform at low power might get it enough awake to charge if it is not at zero as you mention.

Really appreciate your comments.  I like keeping things out of landfill and this one is my personal item . . . dead from not being used.  Kinda like people ~~

On June 20, 2017 at 11:47am
Matt R wrote:

@Sal.  It is not acceptable in the US to dispose of Li-Ion in a landfill.  Many places offer battery recycling so if the battery cannot be revived simply take it there for processing.

I’ve tried to do similar with a Palm Zire battery with no effect, though your mileage may vary.