Ryobi 18V Battery Not Charging - Fixing it to Charge Again - 1161 

After I repair these Ryobi 18volt batteries I place them on a load tester that I made to verify they really work. Just recharging them doesn't necessarily mean they're fixed. Even placing them in a tool, making sure it turns on, doesn't provide much testing. The real test is placing a load to determine whether it’s going to hold up under load for a certain amount of time. The load tester I made uses a 10-ohm 100-watt power resistor with a heat sink and a fan along with a meter showing the battery voltage and the amount of current being drawn. If the battery’s voltage is at 20 volts that means the load is drawing 2 amperes.

this is a very common problem, even with other brands of batteries. It happened to me recently in a similar battery from ryobi, in which a single cell was discharged, and apparently defective, because after being properly charged (separately) it would discharge again, even without use... After replacing the respective cell, it was also discharged. Result: it was the electronic circuit that was defective and made the cell discharge. greetings from Portugal

Awesome - this process worked for me using one of the after-market batteries - didn't let it reach 15V, just reassembled and dropped it into the charger once the bench supply reached 10V, and it all worked fine then. Excellent video - really clear and explained all the necessary detail.

You just earned my subscription! I used your suggestion on a Bissel vacumn that incredibly does NOT allow you to replace the battery! I charged it at 15 volts and 120 milliamps just like you did and BAM fixed the battery! I also have a collection of Ryobi batteries going back over 10 years. I plan on reviving all of them too. I paid $50 for my bench power supply but it has already aid for itself. Thanks!

That’s why I love my 35 year old plug in power tools. They all still work and I haven’t had to pay for expensive batteries or buy new crappy tools.

This is good to see. I've got several Ryobi lithium batteries that are getting rather old. I've also got a couple of lab power supplies that I scavenged from the trash pile at work (I've tested one of them and it works great). I'm surprised they didn't glue the case together. I once took apart a battery for my old Roomba vacuum and they had not only put in security screws, but glued the damned thing together.

I recently did a similar treatment to revive four Porter-Cable packs. They were purchased in 2019 as door prizes for the local woodworking club but before they could be given out, COVID happened. When the two drill sets were finally given, the packs were all dead and would not take a charge. I pushed current into each for five minutes with a charger that was not "Smart" and then each of the four packs took a charge from the Porter-Cable equipment, and the door prize manager was very happy. My theory is that there is something in the internal circuit board that draws a small current, enough to flatten the battery completely in two years.

Nice video, I also use a lot of Ryobi tools ( their commitment to keep using the same battery for most of their tools is amazing) and I’m from Belgium but living already for 24 years in Portugal. Love your videos

Morten, The United States Air Force sent me through electronics school but assigned me to a skillset of systems troubleshooting where I never did component level bench work. I am retired from Verizon after 40 years as a telecommunications technician and program manager. There is no reason that I should not be able to repair my own dead batteries. Thank you for the inspiration! I have a multimeter, of course, and some old power supplies with the voltage and current identified; one with a switchable output. Again thanks.

Sensational salvage of a perfectly good battery!

I processed thousand of lithium cells from recycle laptop computers for my solar battery pack. 18650 cells identical to the Ryobi. I also fixed numerous Ryobi pack from 18v to 24v to 40V. all used 18650 cells. Not only Ryobi but DeWalt, Milwaukee, Craftsman, Black and Decker, Ego. I became an expert in the process mainly build lithium solar pack for the whole house. They all use lithium cell either the round or flat pack. There are two things that always will fix the pack for the Ryobi. 18V or any voltage. 1. unbalance cell with one or more cell defective; the fix is to replace the weak cell but internal resistance needs to match up or guarantee failure again 2. the power mosfet is cooked or damaged board from water or dirt to fix no1. requires a special charger to bring extremely low voltage. 0 - 2.5v back to 4.1V, an impedance tester to measure internal resistance for matching, mismatched of resistance will guarantee failure again; internal resistance : lower is better and all has to closely matched lithium lasts the longest of 25% discharge to 80% charge with slow charge up to 4.1V. 3.2V to 4V is ideal for longest longevity whole pack charge will not work for really weak cell; it requires individual cell charge one at a time to fix no2. if board is good is to simply bypass the mosfet; a simple short to ground of the mosfet will fix it; it is ground switching for the negative mosfet There is more than just charge and recharge; ability to fix requires deeper knowledge and a special charger; I build that special charger NOT sold in any store. I no longer buy any lithium battery pack because there are ton of stuffs out there to runs on lithium. OUr modern world is not possible without lithium battery. EV car is coming up and they all run on lithium battery. Identical cell voltage of 4.1v per cell as power tool pack. Know how to revive lithium battery will open a whole new world of things for free because when anything that uses them that has a bad battery that item is either throw out or sell for dirt cheap. My special tools are special charger to revive dead dead lithium cell, a tab welder, a battery impedance tester and know how. That is what really needs to fix any lithium battery, include EV battery. I build the special charger and a tab welder myself. Lithium battery is the future and here to stay. BTW Ryobi is my favorite brand. I have many power tools of this brand, include garden tools.

The saw is usually called a Jigsaw in English speaking countries. It's now been 52 years since I used Danish every day, so I've forgotten the correct term in my own language (which is crazy). Nice solution to that battery. A bench power supply is a very useful idea. I've used Ryobi equipment since about 1992 & still have some 14.4 volt drill-drivers. Also about 12 different 18+ tools of all kinds. Nice to see another Dane on RU-vid.

Followed this exactly today and battery is happily charging on its charger. Thanks.

Hello from the USA! Very informative video! Owning six Ryobi tools and my fair share of batteries I now know (thanks to you) what to look for when they won't take a charge.

The most readily available means of providing the necessary starting level is a pair of 9V alkaline batteries, Connected in series the represent 18 V. Their initial current into a battery as empty as yours was would be a bit too much, like over one ampere, but you could add a third component in series with the batteries -- 100 ohm resistor and you have 180 mA maximum charging current. Use 5 W wire wound resistor, so it can dissipate the initial heat. Just like with your bench power supply, the current will decay when the battery voltage increases. Of course, you still should have a volt meter to verify the process, starting with a check that all cells are still OK. If any one of them is all the way down to zero, or even reversed, you probably need to do some cell replacement before expecting a successful repair.

It works! Thanks so much. Just saved my first battery and I'm on to the next. Power supply has already paid for itself.

Thank you for the video! I used a car battery charger on trickle charge for 30 seconds, shot it up to 15 Volts! I stuck the probes from my amp meter in the same spots as he used alligator clips, then made some pig tails out of 16 gauge wire to connect the car battery charger.

@ My PlayHouse I just discovered that I made the same exercis with an RB18L20 battery as you do in your video. But I accidentally discovered a way to revive it without taking it apart. Connect two wires with crocodile clips to plus and minus terminals in the Ryobi charger and connect them to plus and minus on the battery. A rubber band can be used for this. Be careful not to mix the polarity up! What I discovered was that when I wet my thumb and index finger and held them against the plus and the terminal between plus and minus the charging started. I also tried to replace my fingers with a 150 kOhm resistor and that worked too. I have not figured out if it is safe to replace the resistor with a short. When I found this out the charging was well on its way, but I think it would be sufficient with just a few minutes to reach a sufficient battery voltage to proceed with the Ryobi charger. It seems to me that these Ryobi batteries should shut down with more juice left in them. By the way, many car battery chargers behave in the same way, they refuse to charge a dead battery.

Now that was a nice and well explained video. Thank you.

Thanks for another entertaining video. I did some battery repairs in the past and refurbished my Gardena robomower battery pack. When reading the many articles on this topic, you could conclude that the BMS should prevent the battery pack from discharging to such a low level. So when you have an undercharged pack, you should ask yourself why it has discharged? BMS partly defective, battery stored at too low temperatures? When 3.7 li-ion cells discharge below 2V or so, a chemical process starts dissolving the cathode and/or anode and the overall performance drops. So even when reactivating a pack in the way shown in this video, you may discover that the pack has lost lots of its capacity or will self discharge rapidly. Would be a pity when you arrive in Portugal and it is empty again... On the other hand, there are worse excuses to find a reason to go to Portugal.

Great video, I have a plethora of Ryobi tools and batteries and this is very helpful I'm going to get a power supply and put it to work. I look forward to watching some of your other videos I also would like to build a battery pack for the home once I get some solar cells up and working.

Excellent video. I have a Ryobi battery that I have been unwilling to throw out for years. It may be too far gone but I'm going to try this out.

The protecting circuit board is protecting the cells against charging. That is pretty cool.

Good fun and extremely helpful. Thank you!

I love your enthusiasm.

When you mentioned about being able to recharge a over discharged pack like this using a 12v battery but the current would be too high, this could be done by using a suitable sized resistor in the circuit to limit the current or any suitable resistive load such as one or more 12v car bulbs.

If you leave the low charged battery in your tool and not charge it , over time your amp charge will drop off and the voltage will become under the threshold for the electronics and will lock the battery out from the charger. A 12 volt charger is fine but one should do it for about 1/2 a minute or so, just to bring it up to about 8 volts surface charge achievement (as it will drop fairly soon, but just to get it over the line and let the Ryobi charger to take over. Just place the internal pack in its receptacle trays and whack it in. Screw it up later. I've done one; it works. If, you have uneven cell voltages, (battery shows full, but you can't run anything,) you need to make all cells differ in voltage by only 0.1 of a volt. Make sure you don't have over charged cell(s) or you need to draw them down. Hook up your simple drill and run to drain. (Obviously a direct relevant cell connection to your drill terminals. Know your positive and negative terminations. Bring up your weak cell voltages. Use a bench charger for this as shown, as you must have all cells within 0.1 of a volt difference between all cells. (I had two at about 1.4 volts. The others were full, but I drew them down.) When all of this has been achieved, there is one more step: On the circuit board the are a series of test points in a small row. They start from an outer edge and head in. There are 4 solder plated holes on the circuit board. One is labeled RST (reset) side by side is a GND test point. Short between these two. Also near is the 4.4 volt test point. Find all this; you're in the right spot. All this is down the monitoring end; not where the power transistor is with it's heat sink. Whack it in the charger and see what you get? (I got all this info from another youtuber.) All these batteries that I'm working on were left for months either in the tool near flat or may be only partially discharged but out of the tool? I'm not sure on the one with two low cells snd the rest were fully charged? I'm thinking may be after you've had a decent run with the tool on any battery, the evening up between cells may take time after a period from the job; so keep it connected for a time? Or that they just drain over months and months in the tool and over that time discharge unevenly as you leave them in the device? Lithium ion needs to stay charged, so take it out of the power equipment to charge but after, let sit by itself, until a check up or use? The old NiCads, I would leave them flat when in storage. Seemed to last that way. Charging those up and not using them, just stuffed them with charge memory...

When the cells lose capacity I just repack the battery with other cells. A fiddly job. I've done a few of these Ryobi batteries including s 5Ah one. It's good they use screws for the case so it's easy to open.

I have probably 4 or 5 that I'm going to try. Thanks for the video

What I found was that when a battery is fully discharged, it does exactly this. The fix I used didn't involve dismantling the battery at all. Plug in the battery, you get the red blinking light, the tick symbol means that the charger is communicating with the battery okay. Wait ten seconds, and remove the battery. Repeat a few times, until the battery indicates it is charging, which is steady red and flashing green. My maximum tries was about 10, I think.

thanks - needed exactly this and I already have the lab power supply

The cells seem to be pretty well balanced on low 0.3 Volts. The balancer is working pretty well.👍👍👍👍

Just buy a rigid tool. They have a lifetime warranty on the batteries when you buy the kit ! Make sure you keep your Home Depot receipt then go online and register. and take the Vin numbers off of the drill the batteries and the charger and you don't have to worry about this headache. Don't charge your batteries if they're not dead wait till they get to at least 25% I have batteries for my rigid tool they're over 15 years old and they still work because I don't charge my batteries until they're down to 15 to 20%

Now I'm going to try it. Thanks

Ryobi should be sponsoring you... I have literally spent over £1,000 on Ryobi products because of your channel!

Very helpful. Thank you and greetings from the U.S.A.

My Bad...Yay You Fixed it ..New thing I learned never overdischarge...thanx very mucho..

Good video to learn about battery salvaging but should have checked individual cell voltages during charging to see cell health/ balance for better diagnoses of battery condition

Great job have a good trip

An excellent video very clear video, very clear instructions. 👍👍

Thanks for this clip!

I still couldn't fix my Ryobi battery and it was just a 2Ah version anyway. My Bunnings (large hardware store in Australia) had a trade in program so it was worth AUD50 towards DeWalt batteries so I saved more than the battery was worth. Plus the Ryobi line trimmer was pathetic that reminds me why I never used it regularly and that's why it died in the first place.

The problem is that discharging lipo cells below a certain voltage is often a death sentence, and while you can recharge them using this, or similar methods, they often never recover back to the same amount of power they had prior, so while it will work it will likely have reduced capacity. going forward. For example, instead of 2ah it might only be be 1.5ah, so will the battery will die sooner than usual going forward and have to be recharged more often. I expect this is the reason they refuse to charge below 12v; Also to ensure tools performs optimally, or to avoid customers complaining that the batteries die quickly. Sometimes you can apply high current pulses to the battery, in order to undo the dendrites that have formed on the electrode, but might not work in all situations (this works on some situations because it causes the electrode to heat up, so flux will cause surface diffusion, which 'smooths' the dendrites).

It looks like that "thing" is likely a current shunt to measure the voltage drop across for measuring battery current. It is also possible a thermistor is under it to also monitor the temperature of the current shunt. These are both things that have commonly been used over the years on various battery monitor circuits.

You guys make a nice couple. those batteries never last

Well done!

Nice. Airways good to extend the life of things.

With the batteries having been left to go so low there may yet be consequences - increased self-discharge or whatever. I don't usually see all 5 cells go down so evenly. By the way, if you use a cheap 12v supply to do this you probably want a series resistor to current limit. The other option would be a CC/CV buck converter which is about the cheapest CC device on ebay these days.

Great video love your explanation🙏🌟‼️

Awesome video thanks I have a battery just like this

Nice video presentation and very informative. I found your lab power supply available here in the states but I also found another one half the voltage but includes a USB port which I think would be most helpful on other devices testing and a four place LED display. As for the voltage draining so deeply on that battery pack I've come across an interesting issue with Ryobi tools specifically their FM radio attachment which apparently has a parasitic draw on the battery even when it is in the power off position which necessitates removing the battery when not using the radio. I have since then always remove the batteries from all my tools regardless of mfgr or the tool when not in use just in case other tools have that parasitic voltage draining.

I called Ryobi and I gave them the serial number, they looked it up and my battery was less than 3 years old and they sent me a new battery!

I've learned from experience that leaving the battery in an unplugged charger will completely flatten it like that Seems to be a design "feature" of the Ryobi chargers

Thanks for the info 👍 I have a few bad ones 👍🇺🇸👍

🇹🇹👉Very nice explanation of the repair of that rundown battery 👏 Keep up the good work 👍

I think it would have been prudent to check the voltage of each cell after charging, and also try to do some work with a tool. Cut a piece of wood for example. Nonetheless, I learned a lot from this video. Thanks.

I like those ryobi boxes / cabinetes

I've "jump started" these types using a higher voltage battery connected to the dead battery... This has worked some of the times to allow the charger to recognize that the battery has some life... A little shortcut from what you did...

I've heard that the lights kill more batteries than anything else if it is left turned on, draining the battery completely dead. But the modern electronics in batteries and tools may have solved that problem?

Don't you just love knowledgeable and helpful people?

Thanks for the video which is very good. Would I be able to do this with a 12volt trickle charger?

Ahahahah....Nice, because I'm watching from Portugal...!!! Great video.

I would recommend taking a look at 'Quick Test Hook Clips' - and go get some ;ø) - they are nearly completely insulated, where only the tip itself is exposed (but it retracts into the insulated tube when disconnected) They are often easier to connect directly onto the battery welding taps directly, and not as the alligator clips onto connections/components on the BMS, where they can easily jump off, then move/slide around and short stuff you really don't want to short. Nice fix, hopefully the cells didn't take any damage from being discharged nearly completely

🐱🐈👍thanks for the valuable information

great video thanks.

Great video about batteries with a balancer board. Many fix powertool batteries videos on RU-vid tend to be the ones that do not have the balancer board on the battery unit. I do have a question for these types of batteries: Suppose that if one does not have a laboratory power supply, one can simulate the same voltage by direct connecting the terminals to a working identical spare battery that is fully charged?

Good job! Btw, do you think I need to worry about the voltage if one cell only reads 1.8Volts as opposed to another that reads 3.8Volts and both are brand new and never used or charged? Purchased them a month ago.

I had what I think was a similar problem, in that it would not charge on the fast(?) charger. I also have a basic slow charger, (both Ryobi) and it would charge on that. Battery now seems fine.

7:12 "If it's good, it's a Fluke!"

Great content!! What’s the name of the video showing how the science charger works? I’ve looked and must be overlooking it. Thanks

Nice easy repair job :-) Shipping costs are a bit high!

Great video, thanks. My problem is that my battery got wet in the rain and now doesn’t work. The charger indicates it is no good. I was going to take it apart and spray with contact cleaner and see if there are any obvious defects. What would you do please?

good job🤗

Nicejob!

Thanks

My Ryobi drill batt did the same thing flashed no good so i stuck wire to pos and one neg used my car bat charger with lythium opp and it charged fine and in only 5 min full charge works great in drill

This is a good way to use a bench top power supply to charge batteries and do it safely.

Is it a Fluke you used THAT multimeter?? Lol. Good video.

Thank you very much sir, i will definitely try this, save me some money..😁

This is a Great Video!!!

What do you recommend, leave the batteries on the charger? I have a Ryobi blower and whipper sniper at my beach house some batteries, one charger transformer gets rather hot and I don’t like to leave it on and in the power point in case it starts a fire. Should I just leave them connected all the time? Thanks. 🇦🇺👍🍺

Great video! I have 9AH battery that failed to charge for couple years now. What Volt and Amp should I start with? Tank you

The Ryobi battery i have just repaired seems to go into a sleep mode in a couple of minutes of no use .If i measure the terminals fully charged i only get 8.5 v no load , if i then put the battery in a drill and operate for a few seconds then take the battery back out and measure it says 20.5v .Leaving the meter connected to the terminals it goes back to 8.5v after a couple of minutes .Battery works fine now , but is this right ?

Would have been interesting to see individual cell voltage after your initial charge. And then again after a couple of days.

Does the battery have a self protect function built in? Will it stop providing power if the voltage drops below a safe voltage, or will it allow the batttery to drain to zero? Maybe the protection is in the tool?

Tanks for sharing that way to fix a battery, but I have a question to you and an advise: Q: why is that you need to disassemble the battery just to connect the charger into + and - ( init and end of 5 batteries in SERIE) if that is the same you do when inserting the battery tower into the charger? Adv: cut the smallest side of your ALLENS and insert that cut side into a drill, as a bit, you will easily remove Allen head screws very easy.

Try giving the battery a short zap from an AA battery. Sometimes that is all that’s needed to fool the charger in to charging a dead battery

I have repaired a few Dewalt and Bosch batteries but had to replace the circuit board because they have a memory so even if you charge the battery and put it back together they register as bad and will not charge obviously to force most people to buy a new expensive battery just because they tried to drill one to many holes, they could make the chargers with a recovery slow charge setting but would lose a lot of battery sales.

Interesting video 👍

It would have been good to see what current the draw was without it connected to anything i.e. was there still a fault on the PCB causing it to discharge, maybe a microprocessor not going to sleep. I would expect a battery to still be ok after at least 5 or 6 months without any work.

Would you be able to connect the battery in parallel to another Ryobi+ battery just so you get some charge into it to be able to continue charging in a proper charger. Or would that damage the inside board?

Am I correct in taking from this, that the circuit board (the balancer?) was preventing the charging of the individual cells? If so, why is it designed to do that? Perhaps there is some other video that explains the reason why?

There must be differences between countries design of Ryobi batteries or versions. For one. The output voltage won't show on terminals unless a load is applied for one I have. Secondly, the bms seems to fail and unrecoverable when cells fail. So it seems some are recoverable but in my experience the bms is programmed to not accepting resetting. I'm in Australia. My Makita batteries on the other hand seemed more fixable and longer lasting. I think Ryobi cheap out on cell quality these days.

I'm racking up boxes of lithium batteries myself - especially finding mower battery packs lately that will charge. I have over 20 of these Ryobi battery packs that will charge to 20v(if i connect straight to battery) but they won't charge if I connect the charger to the BMS. Does the OEM ryobi charger talk to the board telling the bms to switch on to charge the battery or something?

Thank for this interesting video.... do you have a link to the bench power unit?

Have you any experience with Rigid brand batteries? One of my tools got left in the rain and now it tests as charged, all lights come on, but it won't make a tool work, no output to the tool, I'm a mechanic but know very little about electronics, thanks

Funny, I never have any problems with tool batteries. Oh right, I have power tools with cords that ALWAYS WORK.

17:03 Well Mr. Smart they call me The Saw.

Can you fo the same thing by taking a good battery that's charged to about 60%, and jumping the terminals from one battery to the other?

Lithium Ions should not really be used if they went below 2.5v. Heard that they can be short circuited internally due to a chemical reaction