How to Prime Batteries

Caring for the Battery

In many ways, a battery behaves like a human being; it senses the kindness offered and delivers on the care and attention given. Looking after the battery well will return the benevolence bestowed and deliver good performance over a long life. There are exceptions, however, as any parent raising a large family will know, and the generosity given may not always deliver the anticipated returns.

To become a good custodian, we must understand the basic needs of a battery, a subject that is not taught in school. This section teaches what to do when the battery is new, how to feed it the right “food” and what to do when putting the pack aside for a while. The next articles also look into restrictions when traveling with batteries by air and how to dispose of them when their useful life has passed.

Just as we cannot predict a person’s life expectancy at birth, we cannot date-stamp a battery. Some packs live to a great old age while others die young.Incorrect charging, harsh discharge loads and exposure to heat are the battery’s worst enemies. Although we have waysto protect a battery, the ideal situation is not always attainable, and as battery custodians we try to do our best. This chapter discusses how we can get the most from our batteries.

Priming a new Battery

Rechargeable batteries may not deliver their full rated capacity when new and will require formatting. While this applies to most battery systems, manufacturers of lithium-ion batteries disagree. They say that Li-ion is ready at birth and does not need priming. Although this may be true, users have reported some capacity gains by cycling these batteries after long storage.

What’s the difference between formatting and priming? Both address capacities that are not optimized and can be corrected with cycling. Formatting completes the manufacturing process and occurs naturally during early usage when the battery is being cycled. Priming, on the other hand, is a conditioning cycle that is applied as a service tool to improve battery performance during usage or after prolonged storage. Priming relates mainly to nickel-based batteries.

Formatting of lead acid batteries occurs by applying a charge, followed by a discharge and recharge as part of regular use. Do not strain a new battery by giving it extra-heavy duty right away. Gradually work it in with moderate discharges like an athlete trains for weight lifting or long-distance running. Lead acid typically reaches the full capacity potential after 50 to 100 cycles. Do not over-cycle on purpose; this would wear the battery down too quickly.

Manufacturers advise to trickle charge a nickel-based battery for 16 to 24 hours when new and after a long storage. This allows the cells to adjust to each other and bring them to an equal charge level. A slow charge also helps to redistribute the electrolyte to eliminate dry spots on the separator that might have developed by gravitation.

Nickel-based batteries are not always fully formatted when they leave the factory. Applying several charge/discharge cycles through normal use or with a battery analyzer completes the formatting process. The number of cycles required to attain full capacity differs between cell manufacturers. Quality cells perform to specification after 5 to 7 cycles, while others may need 50 or more cycles to reach acceptable capacity levels. Lack of formatting might cause a problem when the industrial user expects a new battery to work to specification right out of the box. Organizations using batteries for critical applications often verify performance through a discharge/charge cycle as part of quality control. Automated analyzers (Cadex) apply as many cycles as needed to achieve full capacity.

Cycling also restores lost capacity when a nickel-based battery has been stored for six months or longer. Storage time, state-of-charge and the temperature under which the battery was stored govern the recovery. The longer the storage and warmer the temperature, the more cycles will be required to regain full capacity. Battery analyzers help in the priming functions.

Some scientists believe that with use and storage, a passivation layer builds up on the cathode of a lithium-ion cell. Also known as interfacial protective film (IPF), this layer restricts ion flow and increases the internal resistance. In the worst cases, the phenomenon can lead to lithium plating. Charging, and more effectively cycling, is known to dissolve the layer. Scientists do not fully understand the nature of this layer, and the few published resources on this subject only speculate that performance restoration with cycling is connected to the removal of the passivation layer. Some scientists deny outright the existence of the IPF, saying that the idea is highly speculative and inconsistent with existing studies. Another layer is the solid electrolyte interphase (SEI), which is said to form at the anode on the initial charge. SEI is an electric insulation yet provides sufficient ionic conductivity for proper function.

Whatever the truth may be, there is no parallel to “memory” of NiCd batteries, which require periodic cycling. The symptoms may appear similar but the mechanics are different. Nor can the effect be compared to sulfation of lead acid batteries.

Lithium-ion is a very clean system and does not need formatting when new, nor does it require the level of maintenance that nickel-based batteries do. The first charge is no different than the fifth or the 50th. Formatting makes little difference because the maximum capacity is available right from the beginning. Nor does a full discharge improve the capacity once faded. In most cases, a low capacity signals the end of life. A discharge/charge may be beneficial for calibrating a “smart” battery, but this service only addresses the digital part of the pack and does nothing to improve the electrochemical battery. Instructions to charge a new battery for eight hours are seen as “old school” from the nickel battery days.


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.

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On July 7, 2011 at 10:21pm
Bob Morein wrote:

A cycle and capacity test was performed on the battery of a Compal CL-50 laptop purchased in 2003. The battery is an 8-cell 18650 unit manufactured by Sony. The llaptop was operated off AC power almost exclusively prior to this test:

1.  Rundown from 100% to 6%, at which point the laptop shut off: approximately 90 minutes, implying 1% capacity/minute of run-time.
2. Complete 100%
3. Discharge to 58%.  Measured 0.7% discharge / minute of run-time.
4. Charge to 100%
5. Discharge to 86%.. Measured 0.5% discharge / minute of run-time.
6. Charge to 100%; laptop unused for 8 days.
7/ Discharge to 88%. Measured 1% discharge / minute of run-time

Contrary to itypical ndustry recommendations, the capacity of this battery is strongly influenced by the usage pattern. However Apple Computer does recommend exercise of the battery that seem implied by these results.

On March 25, 2012 at 9:31pm
ReachLocal wrote:

I agree with this statement for the most part “Rechargeable batteries may not deliver their full rated capacity when new and will require formatting. While this applies to most battery systems, manufacturers of lithium-ion batteries disagree.”

On March 31, 2012 at 9:24am
Casper wrote:

Remember, Cycling a battery do add some wear and you lose some capacity. This is why they do not recommand to cycle lithium battery, specially since they are typically only 300 cycles, so cycing does help, but at the same time kill it a bit. Lithium manufacturer say that it’s not needed because it’s usually not a big gain and would kill the batt a bit. The end result would be a lost.

As for bob morein results, the test is probably invalid due to several factors like power usage. Laptop can vary ALOT in power consumption. Also, some laptop report 100% when the battery is really only 85%. The reason why they do that is to be able to advertise a faster charge rate, 0-85% can be done in 1 hour, 85-100% can be 3-5 hours!

On March 31, 2012 at 12:05pm
Bob Morein wrote:

  I agree with the point on wear, in that I am not recommending a routine procedure. The purpose of the test was to determine what the true life-state of the battery actually is. In the test, laptop was in specific idle mode. On AC, consumption of this mode was determined to be 19W. Also, this is not a fast charge laptop. When new, charge time 0-100% was 4 hours. Time was allowed for laptop to charge according to the percent battery gauge of Windows XP..

  The statement of 300 cycle battery life is not a current figure, but it may be true for some laptops.. Liion 18650 cells are typically quoted at 700, but in some laboratory tests in ideal environment, several thousand cycles have been achieved. . The thermal environments of laptops vary widely. 300 cycles may be valid for an HP or Dell that bakes the battery. In a Lenovo, Asus, or other design where the battery extends from the back, the thermal environment is much more hospitable to long battery life. In the case of some HP batteries, it may be possible to approximate the ideal laboratory conditions. These batteries have a separate power connector on the battery casing for charging, so that it may be charged while not installed in the laptop. In this way, high temperature charging of the last few percent of battery capacity, which is now known to be most damaging, can be circumvented.

  Since Lion was introduced, a number of reports of user actions that appear to temporarily increase battery performance have been reported. In the late 1990’s, I tried these with a Fujutsu laptop that used 18650 cells.

a. Freeze thaw cycle of the battery pack.

b. Sharp rapping of the battery pack on a table. DO NOT DO THIS. This was before the battery explosions in the early 2000’s that accompanied higher capacity cells. It worked; it obviously increased battery capacity, but it is now known to be dangerous.

In all cases I have observed, the first sign of lithium battery aging is that the battery gauge becomes inaccurate on the low end. A calibration cycle does not appear to solve this. The 8 cell 18650 pack of the cycling experiment eventually exhibited this symptom. Capacity would appear to be reasonable until 50% was reached. WIth aging, the number moved up, 60%, then 70%. The battery would then nosedive to 0%.

Perhaps Mr. Buchmann can explain what is going on?

On June 6, 2012 at 1:38pm
Joe wrote:

Thx To all of you for all of these tips!! But all of these scientific words confuse menciuld any ofbyou tell me just what to do to make the battery of my ipod touch 4gen 64 gb hold longer and how not to hurt/ruin the battery of it.

Thx Joe

On August 8, 2012 at 6:54am
Melka wrote:

Regarding on the Lithium battery, I didn’t use the battery of my laptop since I bought last six months, What is the right thing to do taking care care and to prolong the battery life?

On September 4, 2012 at 4:59pm
Awesome Pickles wrote:

this is the nerdiest chat room evar!!!!

On September 28, 2012 at 6:33am
longcat wrote:

I like the information at this site, it’s helped me a lot, especially since I run a blog about cell phone batteries.  However, I have to disagree with the notion that lithium ion batteries don’t need any sort of conditioning when new, or that they are at 100% capacity out of the box.  This graph of me testing a cell phone battery at 500mA load repeatedly shows that capacity increases each time: increasing.png.  I was under the impression that lithium ion batteries didn’t need any sort of conditioning too, and I thought this battery was a counterfeit until I retested and saw the capacity increase… and again…  It turns out that’s not true about lithium ion.  But it seems like the people who believe they require no conditioning are so many and so passionate that I will keep it to myself for fear of being called a heretic and burned at the stake.  Also, this is the review that graph I made is for:

On September 29, 2012 at 9:25pm
bill wrote:

lots of good info here, if you dont mind a layman chiming in ..I needed a new battery for my hp tablet pc
. using hp battery test and Battery monitor, cpuid hwmonitor, all reported my original hp branded battery at 50% capacity from 5200 designed mwh to 3200mwh 1v. age 2750 days old.
bought a $20.00 lion batt on ebay, advertised capacity of 55wh.
hp batt test showed this ebay battery to have a designed 4400 mah and a capacity of 3200 mah. and running at 12.59 volts, very odd. sent it back. replacement battery from ebay, same test data and battery never charges to 100%
cycled replacement ebay battery from 88% (highest charge level it went to before stopping charging.) to 1% charged twice with this method and no change to capacity.
depleted battery to 50% rested, charged, now I get green charge light on laptop and capacity shows increase to 4000mah, repeated cycle twice and now at 42550mah and 92% charge before the laptop shuts off charging.
while the voltage of this battery is showing 12.59 volts and is labeled as a 11volt 6 cell
but hp battery test cant find one of the cells so fails the battery as replace.
obviously a counterfit battery, my research online indicates this is an issue with the internal battery controller programming,
so I created a battery profile that sleeps the laptop at 50% reminding me to charge it,
will try this a few times to see if I can get to that almighty 100%
of note actual runtimes have been around 2hrs with a steady load of 20 watts. same as I get from my half dead 6 year old hp battery.

On September 29, 2012 at 10:09pm
Bob Morein wrote:

Does the labeling on the battery indicate it is made by HP? If not, it is a copy, not a counterfeit. The issue with controller programming is three years old. It may not be the source of your problem, which is common with copies. I think the correct remedy is to do an actual battery calibration,  available in some BIOSes, which discharges the battery further than the indicated 0%, and then charges fully.

One thing I have always wondered is why battery calibration is necessary. I thought battery packs contain coulomb gauges, which detect the actual passage of charge from the battery. On the other hand, if the battery capacity is measured by the voltage discharge curve, each set of cells will be different, requiring calibration of an adaptive algorithm.

Since I wrote the original post, I’ve had some more experience with the effect of discharging:
1. With an old battery, a full discharge/charge cycle usually results in a measurable loss of capacity. It can result in what appears to be an improvement early in the discharge from 100%, but a really old battery seems to fall off a cliff further down the curve.
2.An old Lenovo pack jumped from 29.6 to 36.5 watt-hours after calibration.
3. The makers of battery copies are so varied, and so good at imitation of the outer cases, I have not been able to identify makers of good and bad batteries.
4. Lenovo has a very elaborate battery management utility. None of the copies I’ve purchased have been identified by the Lenovo software as defective. Perhaps this is because they know they will be found out!

On October 3, 2012 at 5:31am
bill wrote:

Bob, no, the label on the battery is generic but indicates 55wh. after several more partial cycles and another deep cycle, my battery is now at 3850mah. software indicates 44wh. a increase in indicated capacity.
the indicated capacity changes with every cycle, up and down, it may be an indication problem or a cell problem but I have no way to determine which . this battery is going back.
I disassembled one of my original hp battery’s and its not rebuild-able for me as it uses ribbon cable spot welded to the cells. it looked like it was just two parallel sets of three in series.
my replacement copy does not communicate properly with the hp software as the battery tests show 12.59v with two cells detected not three., .that’s a volt an half to high. so either the battery controller is allowing the cell voltage to go to high or ?.
In my opinion when I buy something it should perform as advertised and just work. that’s why I called the battery counterfeit because the battery does not do what the label indicates
the internet is full of blogs and discussions of people discussing how to make things work, from software to hardware. as a society we need to demand better.
this run around with a battery is costing me time. and frankly it causes me to seriously rethink making purchases online.
hopefully I can find a battery that works, the search continues…..
Have a great day.

On October 3, 2012 at 8:15am
Bob Morein wrote:

Bill, all the copies I have tested have lower capacity than marked. The actual capacity depends upon temperature. Also, note that durability is enhanced if the battery is charged only when cool, ie., in an unused laptop.

Almost all these copies are based on the cell conforming to the original Sony 185650. I’m guessing that the generic battery makers have the equipment to make these cells, which have simple “jelly roll” construction. But the capacity of branded 18650 cells increased markedly from 1995-2005, by use of thinner foil, and advancements in electrode construction. I’m guessing that these advances, some of which are proprietary, are not found in generic cells. The generic packs I have examined show exaggerated capacity claims. It would seem the makers are claiming capacities that would be reachable only with the newest branded cells.

But this is not a fatal flaw. In my case, a genuine Lenovo battery costs ~150. A copy costs $25-$30.  To me, 10% less capacity is a good tradeoff. I don’t know what brand cells are in your genuine HP pack. But because the Lenovo battery manager provides comprehensive information, users have noticed differences between Panasonic, Sony, and Sanyo packs. Their observations go far beyond the standard table indicating a 6% loss per anum for lithium batteries. Sanyo packs have had notably bad cycle life, failing completely in as few as 250 cycles or two years. Some claims that Panasonic cells have the greatest longevity, followed by Sony, with Sanyo trailing. Personally, I have an Asus pack containing Sanyo cells that failed in perhaps 50 cycles.

So there are a number of outcomes that can cause the purchaser to feel cheated. Someone who spent $150 for a Lenovo pack containing Sanyo cells, which failed in two years would feel worse than you smile

On October 4, 2012 at 1:58pm
Bob Morein wrote:

I just performed a gauge reset on an 8 cell original OEM battery for a Lenovo X61. The battery contains Sanyo cells, has 342 cycles, and was first used in 2008, and an original capacity of 74.88 watt-hours..
Before reset: 42.07 watt-hours.
After reset: 41.15 watt-hours.
The date of the last previous reset is not known. In resets of four Lenovo batteries, only one showed a capacity increase, a considerable 20%. With the other three, gauge reset caused a loss of about 2% capacity.
The extreme capacity loss for 342 cycles is, according to web comments,  typical of Sanyo cells.

On October 4, 2012 at 4:01pm
bill wrote:

Right, I dont expect the same performance for a low cost battery, my expectation was for the battery to last for fewer cycles not lower capacity than advertised. well now I know. so I can pay more or I may go for an generic extreme capacity battery.  my need is for the laptop to run for 3hrs in the field with out swapping out power supplies.
the last two cycles of the new replacement battery I obtained on ebay showed continued capacity loss I was back down to 41 indicated watt hours. thats about two hours on my pc tablet which sucks lots of juice outdoors when the screen brightness needs to be high.
next I will try a generic 95wh battery (another pound and half) and see if I can manage that way. dont look forward to carrying around 6lbs of laptop….

On December 12, 2012 at 4:43am
Ramesh Iyer wrote:

Have noticed in Lithium-Ion batteries of both mobile handsets as well as notebooks that going through full charge-discharge-recharge cycle doesn’t make any noticeable difference in the battery life. Seems this was more applicable to NiMh or NiCd batteries of years ago, which seemed to have a “memory” and hence required to be “conditioned” for the first few charge-discharge cycles.
Incidentally, both mobile as well as notebook retailers continue to “advise” consumers to follow the old routine of few full charge-discharge cycles even with Li-Ion battery-based products, as they perhaps got habituated with this for older products which were NiMh or NiCd based.

On February 7, 2013 at 4:38pm
Psycogeek wrote:

While I would generally agree that li-ion cycling accomplishes nothing, working with raw single cell items, of many types and sizes (not calibrations and unknown metering devices).
Most of the good quality cells never changed much in (within spec) end to end capacity, from doing a few cycles.
The exception to this was some of the junk cells that I have, made in china also of different variety, did change in voltage depression, and capacity retention, within the parameters of my end to end (within spec) cycling.
Never did they improve beyond 2 cycles, and the cells that exhibited the change from cycling were also cells that had a short total life of about 2 years, vrses some of the more premium and brand name cells which lasted longer in general.

On February 8, 2013 at 4:27am
Trevayne10 wrote:

I just deep-discharged/reset my 1.5 year old, 6 cell SANYO PA3817U-1BRS LION laptop battery - it was showing 27% wear level.  (53,000+ mWH original). Not good.

After the reset, it is now showing 11% wear level; I verified the increase in use duration before shutdown; I’m getting about 5.5 hours of use out of my 15” laptop (i5-2410M, 8GB RAM, 120GB OCZ SSD), at high performance power profile setting. This is about what I was getting when it was brand new, out of the box, 1.5 years ago. Works for me.

On February 8, 2013 at 8:52am
Bill wrote:

There is test data that you can compile from blogs, comments and manufactures available online that indicates a possible correlation between deep discharge of lion batteries and reduced cycles or watt hours over time. bottom line, my opinion is the designed capacity and actual performance in the field is determined by manufacturing qc and the battery controller algorithms. invariably battery
failure in multi-cell packs like in the Boeing AC will be traced to a single cell failure as a result of a voltage spike from either an internal or external source that wasn’t clamped before it arrived at the controller. Resulting in failure of the control circuit. by process of deduction we can lean toward the cell side of the control circuit, as only one cell failed. But as we know strange things happen in IC’s when they fail.  I have actually recovered electronic circuits by reverse biasing the total impedance of a circuit. I would never return the device to service but it was an interesting observation.

On June 12, 2013 at 7:27pm
John H. wrote:

I’ve never been one to really “care” for batteries, but honestly my laptop battery died out. Doesn’t last. I just bought a replacement and this has really opened my eyes. A clear set of instructions on breaking in the battery! It actually takes a bit of effort on my part, but as the suggest, it will help the battery last longer and hold chargers longer. Great stuff here guys! Appreciate it. With new gaming consoles like the Playstation 4, people need to be consider how they are initially handling their PS4 controller battery charging, if just in the first week or so.

On July 17, 2013 at 3:21pm
Kaz wrote:

Lead acid requires 50 to 100 cycles? But you don’t really get this in a car, oops! The battery is kept in a charged state by the alternator whenever you run the car, and drains only very slowly due to some low current accessories that are on when the car is parked.

Does this mean that to develop the best capacity in a car battery, we should, 50 to 100 times, leave something on for a while to drain the battery while the car is parked (leaving just enough charge so we can start the vehicle?)

On July 23, 2013 at 7:31am
kwame oduro wrote:

I need sent batters to Africa , how can you help me.

On August 18, 2013 at 1:06pm
Vamp898 wrote:

There is no way to damage your Li-Ion Battery more than unloading it below 20%.

If possible you should plug the battery for load at 40%, minimum is 20%, not below!!!

If you dont use the Battery the perfect state of loading is 60%, at 60% and at room temperature it will live nearly endless.

I follow these rules at my Notebook Battery (2 years old) and it still have 91% of its new capacity.

On November 14, 2013 at 2:00pm
jason wrote:

I recently bought a new battery for my blackberry bold9900 and I just charge the battery untill the green light came on showing its battery full and started using it. Does that mean I damaged my battery or it won’t be reaching its full poetential? Pleas help

On April 22, 2014 at 12:12am
naga rajum wrote:

what is the relation between charging time, voltage , capacity, charging current in lithium ion rechargeable battery.
  supose how much time it will take 6000mah battery charging with 100mA with 4.2 volts.

On May 17, 2014 at 6:56am
Khaleef wrote:

Hello. Please, i need a help on a particular problem. I opened up few bad Laptop Batteries and found single Battery cells in them. Now, i’m thinking of Making a large mAh Power Bank from these battery cells. I need help on how to join the batteries to get a good performing powerbank! Thanks.

My mail is

On May 28, 2014 at 6:33am
noushin wrote:

i used samsung galuxy core mobile 15days was new phone..but i did not charge it 8hrs what could i do..if u have any solution please inform
..m very worrid coz it does not work..

On May 29, 2014 at 8:10am
Blake Kennedy wrote:

I have a question so I’m using a Samsung galaxy note 2 cell phone and i have 8 batteries that I just keep charged with a wall charger and swap out when they get low or die. Is there any harm in this kind of method? also some of them have different mAh capacities and range from good quality to a few cheap ones i got off ebay. Is that going to affect or confuse my phones battery calibration? Could this damage my phone or the batteries themself? I use my phone A LOT which is why I need so many batteries I usually go through 3 fully charged batteries a day full to empty. Which seems like a lot to me seeing As The Note 2 Is Supposed To Have One Of the Best Battery Lives Of Any phone?

On June 11, 2014 at 5:10am
Ved wrote:

I use Intex Aqua style. My phone uses Lithium Polymer 2500 mAh, 3.7v and 9.25 Wh. Unable to find a battery from manufacturer.

So, can I use a battery from another manufacturer with same configuration?

On June 17, 2014 at 11:10am
D.C. wrote:

I really enjoyed reading these articles. Keep them coming!