Have a Ryobi Battery That Won’t Charge? You Can Fix That.

Lithium ion batteries are a wondrous invention that are lightweight and long lasting.  But it’s infuriating when the battery won’t recharge.  You stick the battery in the charger and … nothing.  Guess what? You can fix these batteries that appear to be completely dead.  Read on …

Lime green cordless Ryobi drill.

This post is NOT sponsored by Ryobi.  They do not approve of or endorse this method for fixing a Ryobi battery. AT all.

 

Jump straight to the tutorial and how to video.

One of two things are going to happen as you read this post.  You will either unfollow me due to my pathological boringness or … you will propose marriage.  So get ready to act accordingly.

Since originally posting this tutorial a few years ago I’ve been hoping Ryobi would improve their batteries and chargers. So I was happy to see the development of the newer Ryobi P117 Intelliport Charger. It’s supposed to do a faster and better job of charging your batteries but according to the reviews on Home Depot and Amazon they don’t have this issue figured out quite yet. 

What issue? I’ll tell you.

If you have any sort of cordless power tool, but especially one powered by a Ryobi 18V battery, you have no doubt encountered  the dreaded flashing red charger light.  And if you haven’t … you will.  It inevitably goes like this – you run to the basement to grab your cordless drill because after 10 years of thinking about it, you’re finally going to build that 4 level, Tudor style treehouse with kitchenette.   Or you’re going to hang a picture.

Either way you put your battery in the charger and all you get is a flashing red light, which according to the label on the charger means your battery is defective.  It isn’t just dead.  It’s “defective”.  I’m here to tell you you it isn’t.  You probably left it in the charger too long which weirdly drains the battery.

Your battery is fine. It just needs a little boost.

You Can Fix a Rechargeable Battery That Won’t Take a Charge.

You heard me right.  You do NOT have to buy a new $50 battery.  You do not have to call the company and swear at them because this stupid “defective” battery is only 2 weeks old. (although by all means feel free to do so) You do not have to wait until they ship you a replacement battery to finish your project.  You can get that battery up and working in about 5 minutes.

How to Fix an 18V Battery

What You Need

18 volt rechargeable battery on workbench.

 

 

  • An AC adapter (an old phone charger for example)

Common AC adapter on workbench.

 

  •  A multimeter.   (this is actually optional but helpful … if you don’t have one don’t worry, you can still fix your battery)

Multimeter on workbench with tools around.


Note:  If you aren’t used to doing this sort of thing, or using things like a “multimeter”  this is going to seem crazy and hard and way out of your DIY league.  It isn’t.  


Steps

Step 1. Cut the end off of your AC adapter.  That’s right.  Just cut it off.  It’s for a 10 year old cell phone, you’re never going to use it again anyway. It’s frankly kind of weird that you saved it to begin with.

Cutting the end plug off of an AC adapter.

 

Step 2. Separate and strip off 1″ of each wire.  You have *just* made booster cables!  Good for you.

Positive and negative wires on AC adapter.


TIP:

Black wire = negative     Striped or solid white wire = positive

IT IS VERY IMPORTANT TO NOT MIX THE TWO UP.  


Step 3. Remove the screws holding the battery together.

Overhead view of a rechargeable drill battery on paint splattered work bench.

 

 

For Ryobi batteries it’s a star shaped screw head like this.

A few years ago I bought a kit of weird small screwdriver heads from Amazon.  I initially bought it because I needed a special tip for removing my Macbook Pro cover to replace the battery.  But I’ve used it for a ton of other stuff since getting this kit.

Tip of star shaped screwdriver.


TIP:

There’s a hidden screw under a piece of plastic.  You need to pry the plastic off to get at the screw underneath. I used a very thin screwdriver to pry it off.


Side by side view showing you how to remove small cap on 18 volt lithium battery.

 

 

Step 4. Pull the top off of the battery case.

Top removed from Ryobi Lithium Ion battery.

 

Step 5. Remove the 2 plastic side pieces. They’re the things you press in to remove your battery from your drill.

Disassembling 18 volt lithium ion battery.

 

Step 6. Lift the battery pack out.

Ryobi battery completely disassembled on workbench with charging cells removed.

 

Step 7. Set the Multimeter to read volts.  For testing an 18 volt battery choose the 20 volts setting. This will give you the most accurate reading.  (If you don’t have a multimeter skip to Step 9 and hope for the best)


TIP

Volts are symbolized by a “V” with one or two straight lines over it on a multimeter so it’s that section of the multimeter that you use.  The section under the V with the straight line(s).  Not the squiggly line.  The straight line.


Multimeter on a workbench with a reading of zero.

 

Step 8.  Touching the red probe to the positive (red) terminal and the black probe to the negative (black) terminal, read the voltage shown on the multimeter.  In my case the battery was carrying a charge of 0.06 volts.  Which is *almost* nothing, but not completely nothing.

Testing 18 volt battery cell with multimeter with a reading of 0.06

 

Step 9.  Plug your AC adapter in and using the wires, boost your dead battery.  Just touch the black wire to the negative terminal (the one with the black wire going to it) and the white wire (or striped wire) to the positive terminal (the one with the red wire going to it).  Do this on and off for approximately a minute.


TIP

Apparently lithium ion batteries should be “pulse” charged.  Which means you hold your wires down for 15 seconds or so, then release them.  Then hold them down again.  Over and over.

DOUBLE CHECK THAT YOU ARE TOUCHING POSITIVE TO POSITIVE AND NEGATIVE TO NEGATIVE.


Boosting an 18 volt battery with an AC adapater.

 

Step 10. Test your the voltage on your battery pack again.  It should be higher than it was before boosting.  (Again, if you don’t have a multimeter don’t worry about this – you’ll just have to press on without one)

Mine went from 0.06 volts to 7.58 volts after a minute long boosting session.

Testing a cell on an 18volt battery with a multimeter with a reading of 7.58.

 

Step 11. Put the plastic cover back on the battery pack (just the part that goes into the charger) and set your battery on the charger to see if it will take a charge.

5 cells of individual batteries inside an 18 volt battery.

If you still only get a red flashing light and the battery won’t charge, boost the battery some more. I find the battery charger will recognize that the battery is good again when you boost it to between 10 and 14 volts.

Checking the results of boosting a battery with a multimeter.

Just keep repeating the “pulse” boosting and testing the battery until it will finally be recognized by the charger and you get the green light.

Success with a green light on a Ryobi charger after pulse charging the battery.

 

To those of you who found this subject matter to be on par with spending 3 hours in a waiting room, sorry ’bout that.

For the rest of you?  I know exactly how you feel.  I felt the same way. Let me know exactly how elated you were after you brought your first battery back to life in the comments section.

Here’s a 3 minute tutorial video showing me as I fix my own battery.

How to Fix a Ryobi 18v Rechargeable Battery

You have an almost brand new Ryobi battery that the charger won't recognize and won't charge. Here's how to fix that.
NOTE: Before doing all this, first try to pulse charge your battery by plugging and unplugging your charger (with the battery in it) for 10 seconds. Try this a few times. If it doesn't correct the problem, continue on with this tutorial.
4.65 from 51 votes
Print Pin Rate
Total Time: 15 minutes

Instructions

  • Cut the end off of your AC adapter.  That's right.  Just cut it off.  It's for a 10 year old cell phone, you're never going to use it again anyway. It's frankly kind of weird that you saved it to begin with.
  • Separate and strip off 1" of each wire.  You have *just* made booster cables!  Good for you.
  • Remove the screws holding the battery together. There's a hidden screw under a piece of plastic.  You need to pry the plastic off to get at the screw underneath. I used a very thin screwdriver to pry it off.
  • Pull the top off of the battery case.
  • Remove the 2 plastic side pieces. They're the things you press in to remove your battery from your drill.
  • Lift the battery pack out.
  • Set the Multimeter to read volts.  For testing an 18 volt battery choose the 20 volts setting. This will give you the most accurate reading.  (If you don't have a multimeter skip to Step 9 and hope for the best)
  • Touching the red probe to the positive (red) terminal and the black probe to the negative (black) terminal, read the voltage shown on the multimeter.  In my case the battery was carrying a charge of 0.06 volts.  Which is *almost* nothing, but not completely nothing.
  • Plug your AC adapter in and using the wires, boost your dead battery.  Just touch the black wire to the negative terminal (the one with the black wire going to it) and the white wire (or striped wire) to the positive terminal (the one with the red wire going to it).  Do this on and off for approximately a minute. DOUBLE CHECK THAT YOU ARE TOUCHING POSITIVE TO POSITIVE AND NEGATIVE TO NEGATIVE.
  • Test your the voltage on your battery pack again.  It should be higher than it was before boosting. IF IT IS NOT, THEN STOP. YOUR CELL COULD BE DAMAGED AND CONTINUING COULD BE DANGEROUS.
  • Put the plastic cover back on the battery pack (just the part that goes into the charger) and set your battery on the charger to see if it will take a charge. If you still only get a red flashing light and the battery won't charge, boost the battery some more. I find the battery charger will recognize that the battery is good again when you boost it to between 10 and 14 volts.
  • Repeat the "pulse" boosting and testing the battery until it will finally be recognized by the charger and you get the green light.
  • Reassemble your battery. Your rechargeable battery is now fixed.

Video

Notes

  1. Black wire = negative     Striped or solid white wire = positive It is very important to not mix the two up.
  2. There's a hidden screw under a piece of plastic.  You need to pry the plastic off to get at the screw underneath. I used a very thin screwdriver to pry it off.
  3. Volts are symbolized by a "V" with one or two straight lines over it on a multimeter so it's that section of the multimeter that you use.  The section under the V with the straight line(s).  Not the squiggly line.  The straight line.
  4. Lithium ion batteries need to be "pulse" charged.  Which means you hold your wires down for 15 seconds or so, then release them.  Then hold them down again.  Over and over.

Please direct marriage proposals to my publicist. A certain tool company is *not* interested in proposing marriage to me.  So I’d like to make a point of saying I love these tools and use them all the time. Their batteries and chargers on the other hand, could use some improvement.


OTHER WAYS TO FIX THINGS.


Questions & Answers
  1. Is there an easier way to do this? Possibly.  Some people have had success with putting the battery in the charger and waiting for the red light to come on.  Then you pulse charge the battery by quickly plugging and unplugging the charger.
  2. What voltage does the charger need to be? A 12 volt charger will do the trick. 
  3. Isn’t this dangerous? There is a small chance of BIG danger. So proceed with caution. If a cell doesn’t immediately charge a little bit with this technique, stop. If anything (charger, cells, wires) starts to heat up, STOP. 
  4. How long will the battery last after fixing them this way? Until you accidentally leave it in the charger too long again, or until the battery’s natural death.

 

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*Proceed with caution and follow instructions exactly. Failing to do so could lead to injury.*

Have a Ryobi Battery That Won\'t Charge? You Can Fix That.

301 Comments

  1. Carole Kramer says:

    Can’t wait to try this solution! I may have been draining my batteries by overcharging. I don’t know how long to keep the charger plugged in, because the red light goes on when I plug it in, but shows no indication when the batteries are fully charged. How can I tell when to unplug i

  2. Kevin Schulte says:

    Karen,
    Thank you for the great instructions. I actually used my car battery charger set at 2 amps. This also served the purpose of a voltage meter.
    I was able to revive batterys, saved me ~$150. Also it helped to leave the battery in the lower case for easier reassembly. Thanks again!
    Kevin

  3. David Brooks says:

    Do you have to pulse at a point after the circuit board and prior to the batteries, as apposed to the external terminals prior to the circuit board, which are a lot easier to get to.

  4. Benjamin Dyke says:

    This is brilliant but…I couldn’t get the screws out and the head of some of the screws is now so worn – I was desperate to try this – any ideas?

    • Karen says:

      Hi Benjamin. Try doing what others have recommended. I haven’t tried it yet so can’t say whether it works or not. Instead of undoing everything, repeatedly plug in and unplug your charger at the same pace I recommend you charge the cells. This can have the same effect and reset the charger making it work again. ~ karen!

      • Alex says:

        I have a 40-volt battery and charger for a Ryobi cordless chainsaw which has worked perfectly until now (about six months). I’m getting a blinking red light on the charger. Is there a way to fix his using your method?

  5. Dave says:

    Just when I thought I was going to have to deal with customer service, I found your post and followed it. It worked perfectly – thank you so much!

  6. James says:

    I have a question I have the parrot bebop drone and the batteries that came with it are no good at all I’m pretty sure they even had a recall on them but anyway I put three 3.7 v 18650 li-on batteries together and made my own battery but I have a problem how can I charge the batteries lol shows u on the Internet how to make these batteries but don’t show any thing about charging them all comments would be very appreciated

  7. Phil Easton says:

    Thanks for the great tip.It worked on my 18v battery same one demoed.My old phone charger didnt get the boost so I used a 12v 60hz 20w trickel charger.Worked within seconds.Thanks again Look DIY and saving money Phil.

  8. DAVE says:

    The video needs a follow-up and proper ending. HOW LONG was the “jumped” battery usable AFTER this process? How many recharges or cycles?

  9. michele says:

    it worked like a charm thank you

  10. Brett says:

    Worked on my 18v Ryobi battery!!
    Now what could I use to jump a 58V battery??

    • Yetti says:

      I just used an old ac adapter rated as 30v. I’m not sure if it was from an old computer, or printer…but it worked for my Echo 58 V battery, taking it from an unrecognizable low 1.7 amps to over 14 amps…a couple sparks for extra excitement upon the first contact. :)

  11. Lorna says:

    “Plug in your AC adapter and…”

    Thank god you mentioned that. Saved me hours of “jump starting my battery with no results before re-reading the instructions I barely skimmed over the first time.”

    I reserved a chapel for Wednesday at 3pm. Be there.

  12. David Hatfield says:

    Never charge lithium batteries below 32 degrees F. It creates a fire hazard..

  13. Jim says:

    Does this work for ni cad battery packs?

  14. Terry Hobbs says:

    My batteries will taker a charge but do not hold it for more than 24hrs. Will this process change that?

  15. Leon says:

    Nicely done :-)
    Possibly stupid question, what voltage did you use to boost with? Cellphone chargers are 5V, and unless you’re boosting directly on the terminals of each nominally 3.6V cell, as opposed to the 18V+ pack, I’m not sure what 5V is going to achieve. Because as I understand it, Lithium cell eventually grow “whiskers” of Lithium crystal inside and these short out the cell. The refurb attempts to restore the cell by burning these whiskers away, and that requires some voltage in short bursts.

  16. Jon says:

    Dude,

    You rock!!!
    Just salvaged 7 otherwise useless batteries. Thank you so much!!!

  17. Graham says:

    Ensure that your AC adapter has a DC output and not an AC output.
    Get it wrong and your battery is goosed!!!

  18. Tony says:

    Such a quick and well explained solution. Thanks a lot

  19. joe says:

    What is the OP for the phone charger? I have some all with different OP’s

  20. Greg says:

    This worked for me too! Simply plug in, wait a few seconds, and unplug. Do this repeatedly. Mine started taking the charge after doing it just 3 times.

  21. Tate says:

    Thank you so much for this guide! I had 4 (of my 5) batteries all die, and this has fixed them!

  22. Ashley D May says:

    Do you think a DC adapter would work?

  23. Drew says:

    I am jumping off another battery. I’m not having any success. Any thoughts?

  24. Glen says:

    I got a new charger unit from Ryobi as a result of a recall in early 2014. The new “IntelliPort” charger does not recognize all batteries and I had discarded the defective charger. I just bought an older used Ryobi charger on Kijiji for 10 dollars. While this is not a means of “boosting” the battery, it is another reason why some batteries appear defective (the red light) and will not charge but they are perfectly fine. I think that there are “smarts” in the new charger because all Ryobi batteries have a date on them and the new charger wouldn’t charge a battery over 10 years old.
    BTW, all my batteries are the new Green coloured ones, not the old blue coloured ones.
    I hope this helps someone.

  25. Stephen says:

    Great logic applied.

  26. charles m. says:

    i have all bosch tools. and run only two batteries..2 different type that is..my oldest and bigger is a 18v 4.amh high capacity big boy, i keep it plugged into my bosch boom box cause well its the only charger ive for it..lol the problems with the other battery i got a few years back on ebay. it is induction charging, i.e. Wireless charging and only wireless charging pads can charge them..granted its can charge a fully dead, to full charge in 20 minutes..but the other day i didn’t realize that the barn roof was leaking after a rainstorm…[email protected]#$ directly onto my work bench and yup u guessed into the top exposed side of battery connections. ….i dried best i could. but still get nothing but blinking red light on the dock. what im needing to know is if you can do same TYPE of jump charging like i read about on other post here..?? thanks GO HOGS WPS!

  27. Chris says:

    This method, while it does work, can be very dangerous. As an electronic device designer with experience in designing charging circuits for lithium batteries, extreme caution should be exercised when performing this method of charging.

    The reason the charger will not charge a battery below a certain voltage is a protection to prevent fires. Lithium batteries can and will get very hot and can eventually catch on fire if charged with incorrect voltage or current. When their charge drops below a certain point it can indicate failure in the battery which is why the charger won’t continue to charge.

    The reason you must dissasemble the battery is to bypass the battery management circuit that you see on top of the battery. This circuit protects the battery by managing amount of power going and coming from the battery as well as temperature for the reasons I mentioned above. Nicad batteries operate on different principles so they cannot be compared.

    I am not trying to argue with the author, I just feel that there are some very important safety factors that need to be considered here.

  28. WillieNAz says:

    So after you locate the negative and positive terminals, drill holes in the battery pack so you can easily access those terminals the next time you need to pulse charge the batteries without disassembling the battery pack again!

  29. FRED says:

    I have done this on many Ryobi batteries. About 1 out of 3 will not take a jump start, appearently one or more cells are bad. With 18650 Li-ion cells, they should not be discharged below 2.5 volts, but if they are slightly under that, they can be jump started. All Li-Ion battery packs have charge/discharge (battery management) controllers, that is why when the pack gets to low, the controller thinks the pack is bad and will not charge it
    The question is, why is a good, newer battery, discharging below the threshold? My theory is people keep pulling the trigger until the pack is at it’s minimum, then throw it on the shelf, dead, so it then drains below the safe voltage.

  30. Elv says:

    wow
    this is an art of doing something…. very interesting dude
    just follow those steps.

    Excellent post. God bless your hard work and research

  31. Alex says:

    What if this doesnt work?
    How can I fix a faulty litium battery charger ?
    Brand: Jonsered 58V

    Any help would be greatly appreciated

    • Josh says:

      Did you find a solution to your faulty Jonsered 58V battery. I have one whose single red LED comes on when I press the button. When I try to charge it, the red exclamation point error symbol is displayed on the charger. Using a voltmeter, the battery reads 54V. I will not power my equipment. Thanks, Josh

  32. Michel Schreder says:

    Hi Karen,

    First sorry for ma poor English writing (Because I’m a French Canadian)

    Question: Can I try your informations if I have a pace Maker?

    Michel from Montreal

  33. Jeff says:

    The time it takes to go through this process at a tradies rate it will be cheaper to go out and buy a couple of new ones!

  34. Troy Foland says:

    Amazing hack. It works! Found a 12 year old battery, and dead cordless drill. Two hours later, I’m drilling ! Thank you.

  35. Jonathan says:

    You mentioned any Li-ion battery may recondition, so I am planning to try it on my Ebike 36v 12AH battery. Currently, it is at 14v and has been sitting for years without use. What supply should I apply to it? I have a working 48v lithium ion 14AH battery. I can run this down to about 42v which is ultimately what my 36v battery is suppose to obtain. Would that work? Could it cause any damage to my 48v working battery.

  36. Patrick says:

    Your awesome! I just did your trick to my first generation Ridgid batteries and they are charging and holding a charge now. Thanks for posting the article save me 200$

  37. ken says:

    I have an older18 volt Ryoby bat, keeping it just for a radio and caulk gun, but it has no circuit board and a couple of the cells seem damp. If I could save it cool, if not I”ll have to invest $30.00 or so for a new bat. What do you think?

    • Karen says:

      If it has no circuit board it won’t charge Ken. This fix is for newer batteries that still have plenty of life left in them but erroneously aren’t being recognized by the charger. ~ karen!

  38. Jawahar says:

    Can this technique get used on the Robi 40V battery and the Echo 58 Volt battery?

    • Yetti says:

      Yes! I just came across this article, and it worked perfectly to take my 58v Echo battery from 1.68 volts to 14.5 volts in 1 min. of pulse charging!!
      I just put it back in the charger, and it kicked in…about 1 min of flashing red light, and then turned to green!

  39. John J. Adams says:

    I very much enjoyed your videos and you saved me $50 on a new battery. So I would like to propose marriage. :-)

    Have a wonderful day,
    John

  40. Carla says:

    Thank you . I have looked at other pins telling how to fix a battery and most used a welder or something I am not confortable trying. I am a single woman and a blonde, lol so simple easy fixes I can handle. I right now have 2 different cordless drills with 6 batteries total that wont charge. Was thinking of getting a corded drill bit you may have just saved me some money.

  41. michael barnes says:

    There is another potential issue involved. when you open that battery there are actually several batteries inside. each one provides about 1.2 volts, connected in series until they add up to 18 volts. Int that series wiring, if one battery is actually failed, you will never get to 18 volts. Infact it may prevent the charging from going through to the next potentially good batteries. If you had two bad battery packs you could salvage a good cell out of another one and replace it. You might realize by now that some people have too much time on their hands. Batteries have gotten pretty cheap and come with a warranty. If you have the time to do all of this to save 50 dollars… bless you

    • Karen says:

      Thanks for the “bless you” and “too much time on my hands” Michael, but the reason I do this is not to save $50 or because I have any more time than any other person does in their 24 our day. It’s because (as anyone who does a lot of DIY/handyperson work knows) if you’re in the middle of a job and your battery has died you want to get it working immediately. The reason for this of course is because I am a very busy person who works doing this sort of thing for 15 hours a day. I do not have time to run to the store about buy *yet* another battery in the middle of a job. Pulse charging takes a few minutes. And I certainly don’t have a week to sit around to complete a project while I wait for a free battery to be shipped by the supplier. ~ karen!

  42. The reason lithium ion batteries will not charge is because of the electronic circuitry. Once you allow a battery to get too low it will not charge. That’s the reason lithium batteries are shipped with about a 70 % charge. They can sit on a shelf for years and they will still be partially charged. Once you run a battery to the point of dying, charge it soon because if it discharges any further while sitting on your shelf for six months it won’t have enough voltage to recognize it as a good battery.

    What they article didn’t tell you is almost no batteries are screwed together any longer. They are heat welded and sealed which means you would have to cut them open and glue them or tape them together. Cutting them open gets dangerously close to cutting into a battery cell. Not impossible but not for the faint of heart.

    There are actually machines, maybe in a high end camera shop, that will pulse charge these batteries until they wake up. Sounds expensive if you can find one. It delivers pulses, a tiny pulse makes it past the circuitry that shuts it down, eventually you get enough pulses past to wake it up.

  43. Darryl J Birch says:

    … as for the marriage proprosal, my girlfriend might get upset. I’m going to have to settle hitting “follow” on here instead.

  44. Neal says:

    Unfortunately, this method will not work on Makita battery packs. Makita electronics limit the number of times the pack can be recharged and even if the battery voltage is raised, the Makita charger will not continue the charge.

    • Karen says:

      Well, this fix really isn’t for a battery that’s been charged so many times that it has now lost power. It’s for a faulty board in the battery that doesn’t allow it to be charged, even if the battery is brand new. ~ karen!

  45. sachle says:

    Thanks Karen so much!

  46. leonard says:

    love when a chick knows what she is doing….very confident …black nails…..get some color

  47. bstacy says:

    Karen, make sure to say to check the wallwart’s wires for polarity with the multimeter first; don’t assume what the wire’s polarity is until you run a voltmeter on it. Many different standards out there.

  48. William Jones says:

    Take me to church Karen…. we’re gettin’ married!!!!

    The circuit board in the battery pack is the “planned obsolescence” to ensure consumers go back to buy more batteries. There is no reason they couldn’t program the chargers to do “the pulse” when a low voltage is realized…we have the technology.

    Imagine what we will be faced with when more consumers purchase electric cars … the annual battery scrap rate will be tantamount to a multiple oil tanker spill…. so much for a green energy program.

    Keep up the great videos!!!

  49. Marlan Pelham says:

    Why can’t this “boost” procedure be performed while still in the outer case?

    • Karen says:

      Because you’re trying to bypass the internal computer card where the actual problem is probably coming from. ~ karen!

  50. Steve Gait says:

    Why didn’t you tell me this before I went and spent a small fortune on 2 more cordless drills

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