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 ...
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.
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. (I can teach you how to hang a picture too)
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 it isn't. You probably left it in the charger too long which drains the battery.
Your battery is fine. It just needs a little boost.
This is where you want to go if you're looking for how to boost a car battery.
Table of Contents
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.
NOTE: First try pulse charging.
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.
How to Fix an 18V Battery
What You Need
- A lithium ion battery that won't charge
- An AC adapter (an old phone charger for example)
- A multimeter. (this is actually optional but helpful ... if you don't have one don't worry, you can still fix your battery)
Note: If you aren't used to doing this sort of thing, or using things like a "multimeter" this is going to seem crazy 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.
Step 2. Separate and strip off 1" of each wire. You have *just* made booster cables! Good for you.
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.
For Ryobi batteries it's a star shaped screw head like the one below.
A few years ago I bought a kit of small screwdriver heads from Amazon that has every small, weird, head you'd ever need.
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.
Step 4. Pull the top off of the battery case.
Step 5. Remove the 2 plastic side pieces. They're the things you press in to remove your battery from your drill.
Step 6. Lift the battery pack out.
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.
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.
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.
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.
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.
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.
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.
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
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
- Black wire = negative Striped or solid white wire = positive It is very important to not mix the two up.
- 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.
- 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.
- 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.
- How to Unclog Your Central Vacuum
- How to Sharpen a Push Mower
- How to Replace Carbon Brushes on Any Motor
- How to Mend a Broken Fingernail (because you're surely going to need it after replacing carbon brushes)
Questions & Answers
- 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.
- What voltage does the charger need to be? A 12 volt charger will do the trick.
- 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.
- 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.
Seeing as you're the sort of person to make it all the way down here to the end of this post, you might like to learn how to install a battery operated electric fence around a home vegetable garden.
*Proceed with caution and follow instructions exactly. Failing to do so could lead to injury.*
Paul A Schwahn
The phone charger didn't work to revive my dead battery, so I used my car battery charger on the trickle 2 amp charge mode and pulsed it for 2 minutes (15 seconds on/off/15 seconds on/off/etc.) and that worked. My battery charged up like a champ after that.
Ed
I have a bench-top AC 120 volts to DC 12v for bench testing components that need repair.
I grabbed my Ryobi 18v battery that had worked from July 2018 until two weeks ago. Then my intellichargers said it was defective. Bummer.
I had already disassembled it so i could see the insides so in about 5 minutes after reading your article I had my pulse-charger up and running.
FANTASTIC - IT WORKED LIKE A CHARM.
The reassembled battery is in the Ryobi intellicharger right now. The red test light changed to green "charging" within 5 seconds.
THANK YOU!
Kirk Bradford
Wow!!! Thanks Karen ! I just came across a Ryobi battery fix by you and you saved me 70-100$! I have a batt op Ridgid set with 5+ years on the clock.One stopped charging.Warranty claims are a pain in the ass.Thinking it was my best up charger ,Home Depot got me for that one 46$.Literally pulled the old battery out of my trash,no I'm not a smart recycler... popped it on the new charger 4 times and Blame! We got boost haha! Thank you !
Karen
Excellent! ~ karen
Kevin
Great to know! I just hope I remember it to be able to use it before my brain won't recharge!
Karen
Ha!! ~ karen
Carmen
Girl! You are a genius. I have used the old Ryobi drill once in 3 years since my son gave me his old one. Both batteries were reading "defective." Wahhh. I read your instructions, & my heart sank when it said to unscrew the star screws cuz I would have to locate another tool that I prolly wouldn't have found. I kept reading, building up my courage to maybe try this by some stroke of luck or grace or magic. And when I got to the end it said VIDEO. But there's no video! bummed. But then I kept reading to the part where you said "is there another way to fix this?" And I tried it! plugging and unplugging did it. So I didn't have to stress about finding another tool or opening the cover or cutting an old phone charger wire and all that other messsssssss.
Thanks girlfrien' :)
Karen
Hi Carmen. Glad it worked! None of my instruction videos will air, if you have an ad blocker on your computer. You can whitelist my site on your ad blocker and all the videos will show then. ~ karen!
Max K
Thanks for posting this, it worked for me to revive a "dead" Ryobi battery. A few things I noticed:
I did have to take the battery apart to get past the electronics. Trying to boost via the external contacts did not work.
Prying out the plastic bit do the 4th screw was difficult. I wound up drilling into it with a 1/8 bit which helped lever it out of the way.
I was able to remove those security bits without getting the right driver. I jabbed a narrow flat head screwdriver into the opening. The screws either turned, or the center security nub broke off, which then allowed use of a regular torx T8 bit.
Thanks again.
Mike Donegan
The technique shown, works by charging
A- the individual cells LI - 3Volts, or NiCad - 1.2 Volts - one or more cells can die but the pak will still work, but at reduced capacity. Charge the low cells (you will need a meter to check which ones)
B - the battery pak - 12 Volts, or 18/20 Volts (multiple cells) this will work only up to the 'wall wart' charger voltage, if the 'wart' voltage is lower than the pak voltage, try the A method.
Note - the external charger must be a DC type!, some 'wall warts' are AC and won't charge a DC battery without modification
Note - charging via the external contacts frequently won't work because the electronics in the battery pak work to control the battery charging. If the pak voltage is too low, usually the electronics will lock out the charge function. Some pak electronics count the number of charge cycles.
Dave in St Louis
I followed your instructions to a tee,and was successful. I first tried a 4.5 volt 200 mA and it took too long. I could tell the voltage was increasing,so i used a 12 volt 1000 mA and it took just a few minutes. thank you . I bought this battery at a fleamarket for 5 bucks because it looked new. Then i found your hack and it worked . Thank you so much and sorry I've been married 32 years to the greatest person on the planet. No lie.
Mike Mancil
I’m not sure if this thread is still active, but let me throw a wrinkle in the mix. I took my Ryobi 18v pack apart as described and found, oh crap, it reads 18v; but the contacts on the post read 6v! So the battery shows fully charged on the charger, one little green light on the test strip and only runs my drill for a short time before stopping, although it still shows 17v. Guess there’s some communication issues between the batteries and the controller card. Any way to reset the circuit board?
Yves
It's really worked for me...i saved two batteries ...thanks !!
Andrew Jones
I tried hard to resist leaving a comment, but my over-zealous conscience made me..
So anywhooo, here goes...
This is such a bad idea for a few reasons..
- If a brave individual would like to attempt the fix on this page, please, please, PLEASE do some research beforehand. Read AND heed the general warnings and safety precautions that are usually on or with a battery back. Also find and read the Datasheets and MSDS sheets that are available for Lithium based cells.
- BEFORE TOUCHING ONE SINGLE SCREW, put a meter on the contacts on the outside of the battery pack and measure the voltage. You might be surprised. If no meter, then slap the pack into a tool and if the tool runs, even though the battery doesn't charge, then there is enough current available to inflict pain. If the tool runs, then rubber band the trigger, switch, etc and let it run until it doesn't run anymore. When it stops, remove the pack, wait 20 minutes, then put the pack in the charger. Again, you might be surprised.
- Watch as many Youtube videos as you can about Lithium Based Cells and the aftermath that ensues after they go off like Napalm in your face. It's a pretty fugly outcome.
- Unbalanced cells can lead to an over-charged , over-voltage condition that will trigger the charger to illuminate the failed battery indicator. Just be aware of this before slapping AC Adapter leads across the contacts. Also, please be aware that these battery's have the capability of putting out 10+AMPS at one time. Yes, they are rated 2.0Ah or 2.5 or even 3Ah, etc.. Reminder, that is available capacity per hour. If you're in the packing picking, poking and probing, you very well may unleash 19 or 20 volts at 10Amps between both hands, straight across your chest. Not pretty.
- Last Point I'll make here...Wear Safety Glasses , or clear Face-shield , Gloves and a shirt with long sleeves. Because Napalm in the Face WILL leave a mark...
Be Safe Ya'll...
eric refsguard
any reason you cant just plug your charger into a power cord with an on off switch and cycle the charge that way?
Robert Huff
Reason being the circuit board will prevent that from happening.....Circuit board has to be bypassed and got directly to battery....On top of the fact that it will most likely
damage the circuit board...
Manuel Silva
I have an Echo 58V line trimmer that I was about to send in for warranty, the thing is less than a year old and I couldn't get the battery to charge. I used a Sony 12v wall charger for an old portable DVD player (I think) to pulse charge the battery to hold 17V. Plugged it into the charger and viola', it is now charging the battery. Thanks for posting this, it cost me less than 15 minutes to find all the pieces I needed to perform this feat of engineering wizardry and complete the process. Musta saved me hours of hassle and weeks of waiting for the warranty replacements to arrive. Thank you, thank you, thank you!
Karen
You're welcome, you're welcome, you're welcome! :) ~ karen!
Jon
I have a weird situation -- two Makita 12V batteries, both working fine. Put them in the charger, it lit up red, and then after a while green -- same as always. But then neither battery works, in either my drill or flashlight. Pop it back in the charger -- red, then later green, as if it's charging normally. If it wasn't taking a charge, I'd try the above, but any idea what's going on here? Fact that it's both batteries is especially odd.
K Pike
CTEK offers a car charger designed for Lithium Batteries. Could use the outside contacts on the battery without opening the battery case. Some chargers do not recognize a "dead" battery and will refuse to charge at all.
Reggie
But could this also work with a 58v battery?
Manuel Silva
Yes, see the post about my Echo 58V line trimmer
Bob May
Lots of great info but how the hell do you get the screws out, they have a center pin stopping the driver from setting on the screw...needs a special bit
Bob May
All this is great stuff but how the hell do you get the screws out, nothing fits and they have a center pin stopping the driver from setting on the screw...
Karen
Hi Bob. I have a variety of screwdrivers and specialty screwdrivers. One of them fit. It isn't a proprietary screw head, just an unusual one. Small ones that you would use on laptops or other small things will work. ~ karen!
john sadler
Thank you very much. Maintaining our stay at home under COVID-19 it gave me something to do. I thought about a new batteries for year and just couldn't bring myself to spend the money. Thought about buying a different brand. This worked great. The only real problem was putting it back together, the tabs were a pain.
Thanks again
Vincent Sullivan
Hi Karen; Found your blog when looking for a good explanation to send to a friend on how to avoid the UPS Brokerage fee scam. (Been doing "self clearing" for about 10 years and the nearest CBSA office is only 6 KM away!) Nice write up on that!
Looked at a few other things on your blog and stumbled across this item on jump starting Li on batteries. I have been doing this for years too and it works well - and also works on NiMh and NiCd batteries. It really is only a problem if you are using a "smart charger" Dumb chargers will just go ahead and attempt to charge the battery regardless of its condition. I would like to make a few comments though... I make these comments as a professional electronics/electrical/computer engineer - though I retired from that about 10 years ago and I am now a chicken farmer. I am NOT trying to discourage you from experimenting, learning and developing procedures to fix things. What I am hoping to do is to have your learn from some of the mistakes of others (including myself!) rather than having your own mistakes cost you whatever they do...
First: I watched the video and I cringed to see all of the metal jewellery on your hands and wrists. When working on electrical stuff that may have voltage on it it is a really good idea to remove all metal from your hands. (Long dangling necklace too if you wear one.) If the voltage it high and it is contacted by the jewellery it increases the area of contact with your body and may result in a more severe shock than otherwise. If you must work on something with high voltage present keep one hand in your pocket. This prevents a shock from travelling across your body near or through the heart which would be a bad thing. If the voltage is low but from batteries (which have no "off" switch!) and the jewellery contacts both the positive and negative terminals of the battery a large current can flow in the short circuit and generate much heat which can burn you or start a fire. Similar to this happened to me once in my younger days (~1977). It was a NiCd battery and the metal was the connecting strap with my thumb pressed hard down on it. The strap turned RED HOT in about a half second! I do NOT want to repeat the experience. So... metal off the hands please!
Second: I would not want to trust the colour coding on the wall wart wires. You have a voltmeter there... Please use it to confirm that the wall wart is indeed DC and confirm polarity and voltage of the wall wart. Voltmeters such as the one you are using are very inexpensive and I believe that anybody who is trying to do such procedures as you suggest would be VERY wise to invest the $10.00 - $15.00 to buy one. It would add a lot more "certainty" to the process. Also important is to use a wall wart of a suitable voltage. For an 18 volt battery a wall wart of 12 to 15 volts should be about correct. One thing to note about wall warts is that they usually have very poor voltage regulation. In other words, the voltage will be significantly higher than the stated voltage if the current being drawn from the wart is much lower than its stated current rating. You can check this with your voltmeter, which is a very light load. It would not surprise me to see a 12 volt DC wall wart put out 15-18 Volts under no load conditions.
Third: While I think that some of the doom-sayers in the comments are overstating things a bit it is certainly true that batteries, especially Lion batteries, can do some very nasty things if you abuse them. If I were following the procedure you used I would add a small incandescent light bulb (say 12 volt and 1/2 amp rating which is a 6 watt bulb) in series with one of the leads from the wall wart. You can buy such light bulbs (and a socket with wires to hold it) in the automotive sections of Canadian Tire, Princess Auto or any good auto parts store. What this does is add the resistance of the light bulb in series between the power from the wall wart and the battery you are trying to jump start. This resistance will act as a "current limiter" which can keep things from getting too far out of control if things go wrong. One useful characteristic of incandescent light bulbs is that their resistance increases greatly as they heat up and start to glow. This means that if everything is under control and the current is low the light bulb's resistance will be low, it will not glow, and it has little effect on the process. If the current starts to increase the bulb's resistance increases which limits the current flow and the bulb will glow giving an indication of higher current flow and that something is wrong. Very crude but very effective. We engineers call this a "high positive temperature co-efficient of resistance" but you can just call it a current limiter.
I hope this gives you some food for thought. If it prompts any questions feel free to send me an email.
Vince