This is a public record of my personal battery tests.  I welcome your input and ideas.  So far, I am having some luck with reviving batteries by surging and freezing.


Updated Jan-02-2011

Surging Batteries

I save my defective batteries in a box.  These batteries will not charge any more and have a voltage of 0 Volts.  A 12V solar panel, which  provides a relatively safe voltage, brought these batteries back up to a normal AA voltage with just a few seconds of surging!


After surging the batteries, as shown in the video above, I looked for an application where I could use just a single battery to provide power.  In order to test the capacity of the reclaimed batteries, it seems best to test each one on its own and not mixed with other batteries.  There aren’t many electronics that use just one AA battery, but here are some:

  • Flasher LED’s
  • Newer LED flashlights  (I don’t have one of these, though)
  • Clocks
This clock uses a single AA battery for power.

This clock uses a single AA battery for power.

I have a couple clocks that each use a single AA battery.  So I popped reconditioned batteries into them and they are working!


The clock above ran on a reconditioned battery from July 8 until August 5, so almost one month.  The interesting point here is that the batteries used to be at 0 Volts and would not charge up, so were destined for the trash or recycle bin.  But after zapping them for a few seconds with a solar panel, the batteries are again back to work doing something useful.

Battery Charging after Surging

The results are not perfect.  I waited a couple days after surging before doing anything with these batteries.  The result is that more than half the batteries went back to 0 Volts.  I believe if I had tried using the batteries or charging them right after surging, the results would have been better.


As shown in the video above, since I waited a couple days before doing anything with the batteries, many of them returned to 0 Volts.  I performed the surging experiment one more time and had much better luck with the batteries, as shown in the video below.


The good results continued.  After most of the batteries charged up, many of the batteries became useful.  I am using some of the reclaimed batteries to power:

  • Wireless headphones
  • LED flashlight
  • Clocks
  • Cordless laser mouse



Surging the dead batteries brought many of them back to life and gave them new purpose.  However, they are not good as new and probably have some issues with charge capacity.  But for me, I’m glad to have many of these batteries back to work instead of sitting in a box as scrap.

——— -

Freezing Batteries

I froze a battery pack and saw the voltage of the pack climb from 6.9V before freezing to 8.4 V after freezing.  I did not surge the pack.  Freezing by itself improved the voltage.  The battery pack came from a Spykee robot.

Related post:  Repairing and Replacing Batteries on a Spykee Robot

It’s OK to freeze NiCd, NiMH, and Lithium batteries. I think freezing disrupts the crystals that are causing the plates to short together. After freezing, hit end of battery with soft hammer to break crystals?  [ Source: ]

It might not work with Lithium batteries [ source ], although Lithium batteries should be safe from damage even as low as -40C [ source ].

Lithium batteries will not be damaged in freezer as long as they are allowed to warm again before use [source].

A well-written procedure:  Hackaday.

Give a Lithium Battery a New Function

My notebook computer uses a Lithium-ion battery.   This kind of battery typically lasts between 2-3 years.  I have one in storage now after it got too weak to keep the notebook powered for long.  Why do Lithium batteries stop working?  Oxidation inside the battery increases the internal resistance. The oxidation builds up over time and eventually, the cell resistance reaches a point where the pack can no longer deliver the stored energy even though the battery may still have ample charge!  For this reason, an aged battery can be kept longer in applications that draw low current.  [ source ]  So, while my old battery pack might not be suitable for the notebook computer any more, maybe I could use it to light up a few LEDs, power a portable radio, a portable media player, or a micro-controller (like an Arduino).  I’m glad I didn’t throw the battery pack away.  I’ll have to try using that battery pack again for a small application.  First, I have to figure out how to tap into the power connector of a Lithium-ion battery.

Store Batteries at Low Temperatures

Lithium batteries keep their storage capacity better if stored at 0°C and at a 40% charge level.  Some reserve charge is needed to keep the battery and its protection circuit operational during prolonged storage.  [ source ]  This means we could store Lithium batteries in the freezer for improved longevity.

NiMH and Lithium Are Different

Lithium batteries do not like to be fully discharged and fully recharged.  They prefer partial discharges with frequent recharges.

Exercising Batteries – My Personal Notes… Work-in-progress (might update later)

Using an Arduino microcontroller, I exercised some batteries by having them turn LED’s on and off until their voltage dipped below a threshold voltage.

Used this NPN transistor:  ON Semiconductor BC547B.  Data sheet:

The BC547B transistor can handle a maximum of 100mA.  The LED’s I’m using fall below this limit, so this transistor is OK for this application.

My red LED consumes 15mA.

Blinking LED takes up to 13 mA

Blue LED:   up to 65 mA

    • Blinking LED takes up to 13 mA


  1. Chris Bodragon says:

    I have been experimenting with surging a Makita 24v battery pack in order to bring it back to life. Surging once did restore the pack a little and surging again, a litle more. Three times and pack was still improving. Having read up on this procedure, I learnt that the surging “shatters” the large dendrite crystals that build up which cause the so-called memory effect. My guess is that because these NiCd NiMh packs contain 20 cells that are connected in series, each surge procedure is restoring the pack one cell at a time. Would this hypothesis have any truth to it? I am midway restoring a pack right now, (10 surges so far, each one followed by a discharge in the drill), and after each surge, there seems to be more power to discharge. Once I get to 20, I intend to put the pack in the charger and see what I get then. By the way, yes this procedure does warm up the battery pack quite considerably but have been very careful to restore the pack to room temperature before going on to the next surge sequence. If this turns out to be successful, I would like to build a semi-auto surge unit utilizing a mechanical car indicator flashing unit along with some sort of electronic timing system that will allow the battery pack to cool between surges, say a 30 minute wait between each surge sequence. Any thoughts, or is this a mad, dangerous idea that I should abandon right now. Thanks in advance. Any comments gratefully received. Chris Bodragon.

  2. Earl says:

    You seem to have experienced some success already with your battery pack. The dentrite crystals, as you called them, might also be broken if you freeze the batteries. Putting the battery pack in a freezer is another option for you. And there should be no danger in freezing NiMH batteries.

    However, in my tests, most batteries did not recover a good charge capacity, as they did when the batteries were new. The voltage of the battery might look good, but its ability to hold energy was diminished. If you are using the batteries in a drill, a power tool that requires substantial energy to operate effectively, you could be disappointed in the battery performance, but I hope that it would work well for you.

    I also had some cordless drills and every battery pack went bad. It’s hard to use a cordless drill without a working battery. I would have liked to have restored the battery packs, and I hope you have good results.

  3. Kenswa says:

    I bought a new Li-ion battery for a thinkpad that I use as my mobile travel pc. I charged it to 100%, and shutdown the laptop (so i thought). 6 weeks later I tried to boot up the laptop on battery alone, but it was completely dead. I plugged it in, and when 7 booted up it gave me a message about improper shutdown. I realized that the the laptop must have gone into sleep mode when I left it sitting after I charged it. The battery refused to charge, even a little.
    I read on batteryuniversity website that lithium batteries have a protection circuit that prevents them from charging below a certain voltage as there is too much risk of explosion or fire. I also learned that 3 out of 10 Li-ion batts fail because of this reason. I then that a company called Cadex makes a battery analyzer that scans a battery, and then gives it a surge for a certain length of time, to “awaken” the batt., and bring it up past the minimum voltage where it goes into sleep mode, so it can be normally recharged. I could find no companies that do this procedure and I cannot afford to buy the machine from Cadex. So I contacted the company that sold me the battery, and they sent me a replacement, but did not want me to send back the failed battery.
    I decided to check once more on the internet and came across someone who claimed success after wrapping a Li-ion batt in several layers of newspaper, and freezing for 3 -7 days, then letting the battery warm up completely for a day, and putting it back in the machine to charge. I put my defective battery in it’s box and froze it for 4 days 1 day to warm, and back into Thinkpad, and VOILA!–I have another working battery! Somehow, maybe freezing the battery is raising it’s voltage past the “sleep cutoff” so that the protection circuit has stopped preventing it from being charged? I should have tested the voltage before and after freezing. maybe someone else wants to try that, and post the results–as it’s too late for me–at least with that battery. I have put the original dead battery (that made me buy the first new battery)in the freezer today, but I am not so optimistic as it caused the laptop to freeze when it was installed in the computer. It is well worth while to try this–maybe my first failed new battery worked only because the cells are new (just dead) but it sure makes a person happy when these weird fixes actually work. Batteryuniversity has some great info and links–good luck everybody–don’t forget to share your success stories!

  4. Kenswa says:

    I forgot to caution y’all….

    If you are putting away a laptop with installed Li-ion battery for a long time–make sure that it is SHUT DOWN, rather than hibernating or asleep, so your battery doesn’t fall below the “Sleep” voltage and trigger the protection circuit. You can also remove the battery, so you are sure that there is no draw on it. I’m doing that from now on.

  5. Earl says:

    I am glad for your good experience with freezing a dead battery, letting it warm back up, and then your battery accepted a charge. Thanks for sharing your experience.

  6. donjoe says:

    How are you connecting the high-voltage source to the dead battery though? In parallel (plus-to-plus) or as a short-circuit (plus-to-minus)?

  7. Earl says:

    I connected the two in parallel (positive to positive and negative to negative).

  8. Andre says:

    Hi, I’ve have some strange failure modes on NiMH here.
    My recent claim to fame is rescuing “dead” 2500 and 2700mAh cells from the garbage bin at Jessops and reviving them, finding that 100% are perfectly OK.
    I discovered that the cause of the problem is in fact overcharging and if you discharge these down to 0V (actualy 0.7 is fine) and recharge twice at low current they recover nearly all the lost capacity.
    It is actually a big annoyance on solar lamps as these are chronically overcharged and high capacity cells lack the ability to absorb this without damage and as a result suffer severe voltage depression due to one form of the MH (delta) changing into the alpha lower voltage form that yields a pack voltage too low for the lamp to run for long.

  9. steve says:

    I make homemade water batteries, they supply power for years non stop, never need recharging. You can wire several water batteries in series to also recharge a regular AA battery, or recharge several AA batteries in parallel with water batteries. I posted some vids on youby tuby click my name.

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