A Simple Step to Revive a Dead Ni-MH Battery

127,047

153

43

Introduction: A Simple Step to Revive a Dead Ni-MH Battery

Hello,

This is my first instructable. In this instructable i will show to all how to revive a dead battery( means the battery wont charge and will show 0V reading).

A few deays back i bought a pack of Ni-MH battery of 2400mAh. But some in them was not charging. So i had to search a lot to find a proper solution to revive the battery. So let me tell you the steps through which i got them working again.

Step 1: Cheking the Battery

First let us check weather the battery has any juice left in them after charging them for a while so that we can confirm that the battery is dead.

Here in the image you can see a dead Ni-MH battery.

Step 2: Reviving the Battery

Next we must take a similar battery of the same mAh which is fully charged.Then we have to connect the positive terminal of the fully charged battery to the positive of the dead battery and similarly connect the negative terminals.

Let the batteries be connected for a few seconds almost 20-30 sec. Then immediately check the battery voltage of the dead battery, if u see a reading above the 0 value then you can be sure that the battery is revived.

If the battery is still dead try the step again, i had a problem with 1 battery which did not work for this step the first time, later after some 3 tries it worked and is good as new. If you are still having problem check weather you are using a full charge battery for reviving the dead one.

Ones the battery is revived charge it until it is full.

That's all for this instructable.

Step 3: Explanation

"Some batteries die when a short developes between the positive and negative terminals of the battery This happens a lot with NiCd batteries and can happen with other chemistries. The short is caused by a metalic dendrite crystal. The electric charge between the two terminals of the battery encurages dendrite formation.

by connecting a fully charged battery to the dead shorted battery you willl get very high current flow through the dendrite. That will casue it to get hot and melt. Hopfully that breaks the short. Modern lithium ion batteries rarely short out in this way. Also lithium ion batteries are very sensitive to overcharging. If they overcharge they can catch fire . So I would not recommend this with lithium ion batteies." Thank you steven4872 for the explanation.

Be the First to Share

    Recommendations

    • Tinkercad to Fusion 360 Challenge

      Tinkercad to Fusion 360 Challenge
    • Trash to Treasure Contest

      Trash to Treasure Contest
    • Make It Modular: Student Design Challenge

      Make It Modular: Student Design Challenge

    43 Comments

    0
    Matthew Yang
    Matthew Yang

    16 days ago

    I just put them in my no-computer solar charger so that there is no charge computer in the way to prevent the batteries from charging. That will force some charge into the battery.

    0
    urbansprawl
    urbansprawl

    Question 2 months ago

    When I put one particular AAA NiMH into a smart charger (one battery per
    channel), the charger LED blinks that the battery is "no good."

    I put the battery in a different channel, and it gets the same no-good
    blinking message, suggesting the battery is truly having a problem. I
    put a different battery into the same channel, and it charges properly,
    suggesting that channel is working properly.

    I left the battery in the charger for a few months, blinking away, because I was busy.

    Today, the battery was still getting a blinking from the charger. I [finally]
    checked the battery, and it's 1.3 Volts. The battery isn't shorted, so
    there's no dendrites that need vaporizing.

    The voltage is just right, so what is the error trying to say with it's error-blinking?
    Perhaps it detects that the battery's capacity has diminished "out of spec?"

    Thanks,
    Sprawl

    0
    Matthew Yang
    Matthew Yang

    Answer 16 days ago

    It's a broken charge computer. You have an old smart charger/battery analyzer that has a single charge socket with a bad computer (you will find that each charge socket will have a single computer to analyze the battery in smart chargers if you open one up). Get a replacement computer and insert it.

    0
    riverrock83
    riverrock83

    3 months ago

    Batteries are rarely perfectly balanced, so if you let one get entirely empty, while in series with another, it can become reverse charged (as they will be connected -+-+ in the device). This is especially likely if you mix and match batteries of different ages / capacities / brands.

    Smart chargers will refuse to charge these batteries as they think you have them inserted the wrong way. You therefore need to induce a small amount of the correct charge into the battery so a smart charger will allow charge.
    This method is one way to do it.
    Can also use another power supply (including a non-smart charger), so long as it is current limited to avoid a fire.

    Once the charge is reset, your normal battery charger will do the rest.

    This method will often successfully revive a dead battery - it wont rejuvenate a battery which has been used too many times.

    0
    greatzion33
    greatzion33

    3 months ago on Step 2

    Ohhhh my God👏🎉👏 it worked, I just can't hold it..... Woooowwww... Was about loosing my job, I decided to try this.... Thank you so much sir. God bless you.... Thank you thank you thank you... 🤸🕺

    0
    MarkFromNJ
    MarkFromNJ

    8 months ago on Step 3

    Using another battery to burn the short works but it’s a severe treatment on both batteries. There is another way to do it. Get yourself a 4700uF 35V or thereabouts capacitor. Charge it to around 25V with a bench supply. If you don’t have a bench supply a 12V car battery will also work. Connect the capacitor to the battery. Battery plus to capacitor plus, and minus to minus. Try not to use extension leads as they reduce the peak current, and if you do need an extension lead make it as short as possible. You may see a small spark as you make the connection. This is normal. Immediately remove the capacitor. You’re done.

    This is less stressful on the battery because it delivers a higher current for a shorter time. Exactly what you need to burn out a short. When the battery voltage rises above 1 volt during charge, you know you’re done. If it doesn’t work after a few tries the battery is probably not recoverable.

    This method avoids damage to the donor battery which can occur when you short it.

    Dendrite formation is a long-known problem with NiCd and NiMH batteries. If you store them past the point where they self-discharge to zero they will usually form dendrites. Both of these repair approaches may work. Sometimes it just blows a hole in the internal separator and the battery fails to hold a charge. But it’s worth a try anyway.

    0
    enjoybangkok444
    enjoybangkok444

    10 months ago

    Awesome hack, worked with 2 dead AAA Ni-Mh - my "intelligent" charger refused but short cut 2 times for the 1st one and 1 time for the second one did the trick. Thx so much!

    0
    Poppasmurf1301
    Poppasmurf1301

    1 year ago

    Can I use a regular AA 1.5v battery to recover a nimh rechargeable AA 1.2v battery?

    0
    agperrin113
    agperrin113

    1 year ago

    Yes sir! I just revived 2 old batt packs.
    Each 8AAA 9.6v 650mAh.
    Thank you paul1212.

    20200921_143647.jpg
    0
    Rajesh D
    Rajesh D

    Question 1 year ago on Step 2

    My 1800 mAh Ni MH batteries are not retaining charge even after slow charging in 60 mAh charger. Is there a solution ?

    This worked brilliantly. I found 12 Nimh batteries that had been stored for rather a long time (at least 5 years) and only about half would charge in my 'intelligent' charger. The charger is supposed to be able to 'jump start' batteries that are in a 0v state and this worked for 3 of the 6. I had resigned myself to bining the last three (which would have left me with an odd number of two different brands and capacities) but then I saw this and gave it a go. Bingo, it worked. The remaining 3 batteries now charge and last as long as the others.

    0
    PhilE1
    PhilE1

    2 years ago

    Worked for me. Thanks.

    0
    yuletak
    yuletak

    2 years ago on Introduction

    My battery was showing 1.2V, but my charger considered it bad. I charged it per your instructions, and the voltage ended up at 1.33V, and then my charger considered it still good. Thanks!

    0
    leonicholson7
    leonicholson7

    3 years ago

    Many Thanks:

    I received a $50 "eBay Parts Only" iRobot Roomba 650 vacuum cleaner yesterday.
    The iRobot OEM nicad battery was completely dead and measured 0 volts.

    I connected
    the positive to positive, negative to negative terminals from the 0
    volt battery to a spare battery for 20 seconds resulting in the 0
    voltage gaining a fractional value, just enough to activate the charger.
    I put it in the Roomba and charged overnight.
    Ran it until exhausted today for an hour and 53 minutes.
    It is now charging normally on dock.

    0
    WilliamR239
    WilliamR239

    3 years ago

    Nice one thanks bro worked great on one of my rc car batteries thanks again

    0
    JoeH242
    JoeH242

    4 years ago

    Thanks for this insight. I had two AA Nimh in my Wii Remote, one had a NEGATIVE charge of -.71 volts. I thought I'd have to throw out the battery because my charger wouldn't charge it. I connected it like you said and left on for about 20 seconds. It was still negative, I did it again for another 30 seconds and voila! It was at .72 v positive. Then the charger would take over. Weird, but it worked - thanks again.

    0
    MaciejP12
    MaciejP12

    4 years ago

    It worked for a dead 5000mAh pack - I revived it with a 2200mAh fully charged one. It took a mere 20 seconds. Thanks a lot!

    0
    mr.peter.donoghue
    mr.peter.donoghue

    5 years ago

    This worked with Midland BATT5R .. A battery pack with 3 unknown Ni-MH inside !

    I simply connected the output terminals to a similar 6V source and then the pack would recharge - Interesting - there are 2 sets of pickups / contact on the pack - 2 are used for charging within the radio and 2 are used for output - Checking with a volt meter I was getting a reading from the output terminals 6.3 Volts BUT there was no reading across the charging terminals 0.0 V !! .
    I thinks Stephen4872 explanation about metalic dendrite crystal might explain a lott- I thought these batteries were complete gone ! -and was actually look on Ebay & Amazon for replacements when I happened across this site -

    Thank you Paul1212 - you saved the day ..

    0
    DavidC461
    DavidC461

    5 years ago

    Thank you so much for this Instructable! I easily revived 3 dead AA Ni-MH batteries. 2 worked after one 25-second cycle and 1 took two 25-second cycles. This is great considering I have a "green thumb" and didn't want to throw these away!

    0
    Saiyam
    Saiyam

    6 years ago

    Is this really possible? If yes then only with ni-mh? I think you should post a video to clearly show that.