Have you ever run into this issue? Did you end up just replacing the batteries?

I have just tried this with my Milwaukee 18v battery that has been dead for 4 years. It absolutely works beats paying $100’s of dollars in batteries. Thanks brother love your work….

The wife here. My hubby ran away from home. Left me with some old Ryobi tools and DEAD BATTERIES. I'm so blessed to find this process. I have friends with working Ryobi batteries. Now I can fix mine. Thank you!

I have several 40V Greenworks outdoor power tools; mower, trimmer, leaf blower. About 3-4 years ago one of the expensive (more then $100 at the time. They've come down in price since then) 5 amp batteries stopped working. Wouldn't charge, wouldn't run. So, having nothing to lose, I took it apart. On top of the batteries is a circuit board. On the circuit board was a flat automotive fuse, soldered into 2 slots on the board. The fuse was blown. I unsoldered the fuse and pulled it out. Got a new one of matching amperage from my tool box, trimmed about 1/8" off of the blades so it would sit low on the board like the original, and soldered it in place exactly like the original. Worked perfectly. I'm still using that battery.

What is occurring here is that the battery packs contain a fuel gauging and safety IC. The charger must communicate to this IC, before the battery can charge. If the battery gets to a low enough voltage, the IC will be unpowered, and unable to communicate. There is a way in most of these IC solutions to provide a slow charge path for a deeply discharged battery. The issue is that some manufacturers, because of their cell chemistry, don't want a battery which has dropped below about 1V per cell, to ever be used, as it can cause plating of the current collector materials into the carbon matrix, which can then become energized when the cell gets charged, resulting in shorts and localized heating, which can then lead to what is referred to in the battery industry as "rapid disassembly", more often called an explosion by consumers! If the battery reaches low voltage because it was stored uncharged, and left in that state for a long period, it would typically take multiple months, it may reach a low voltage. Such cells are usually safe to recharge, but to be sure you really need to get the info from the cell makers datasheet. The other reason the cells can reach such a low voltage, is because they are wearing out, and their impedance is increasing and capacity is starting to rapidly decline. This can cause a cell to go to zero volts during storage due to increased leakage currents within the cells. Such cells are typically unsafe to recharge! If you are going to do this, be very careful. Recovery of such packs is at a greater risk of catastrophic failure for the cells. Watch such packs carefully during charge, and even for half a day after the recharge. I have seen cells fail after such recovery charging as long as 8.5 hours after charging was complete. A single fire can cost you much more than the price of a replacement pack. I wanted to make sure people are warned of the potential consequences. Please be extremely careful. I highly suggest replacing such packs unless you know they were stored uncharged and left for a multiple months. Li based cells are fickle, they contain tremendous energy. When things go bad, they go bad quickly and violently. Please take this warning seriously. I would hate someone to lose someone they love to such a senseless accident!

Just came across this video and had a DeWalt 20v battery I was about to take to recycle it. Figured I’d give this a shot, and you just saved me a battery! Working again like a charm!

I did that scissors trick when I was 4 with a 120v outlet. Much more memorable. Now that I am an 61 with a EE degree I would recommend a fuse and alligator clips.

THAT'S AWESOME!!! It's just like boosting a car battery with another car battery. Thank you one million times!!!

For the 18volt dead battery, instead of wires or scissors to charge off of another 18 volt battery. Just use a typical 9 volt battery and place upside down on the prongs for about a min. Should send a charge to get it recognized by the charger. Super easy!

My procrastination finally paid off! Have several of these batteries in garage intending to go to recycling. Yay!! Thank you!!!

3-5 minutes might be generous. It can be a lot faster. I learned this last summer from a different video and listed much shorter times. So I tried what they said. 20v dewalt - I connected the wires for about 30 seconds and that was all I needed to have just enough juice to get the charger going. I'm glad people are sharing this information. Seems a shame for batteries to be getting tossed / recycled unnecessarily.

Totally works. Did it with Dewalt 40V yard tool batteries. Took about an hour to reach "threshold voltage" that the charger would recognize. Thanks man!

Wow .. 😊. I have a newer DeWalt driver . One of the batteries went to no charge mode in no time. Came across your video. This works like a champ . I can't thank you enough. Now I will dig out some 18 volts and try those....thanks again👍

An excellent video. This illistrates the principle that a good battery sacrifices toward a dead battery. They will share the electricty equally. In the old days truck mechanics used this to start an exhausted battery.

Oh wow, wished I had known this a few years ago, would have saved me lots of money in new batteries. Thank you!!

Thanks for this great tip. I used your method on my 20 volt rechargeable battery and brought it back to being able to charge it fully again.

Thanks! You just saved me money. I was just about to get a replacement for a battery I thought was dead. Thanks again.

Thanks for helping me to save money once again! You ROCK Brother!!!

I wish i had seen this before I bought a new drill battery. Thanks so much for the tip, and you always have good info.

Super advice thank you, I have done this a few times, recently on those solar lights that gets too low during winter and can't charge in the spring

Wow! I tried it on a Ryobi 40W battery with speaker wire and the technique worked. Thanks.

Love your channel! Concise, short, but extremely informative. Great job!

I haven’t had this issue yet. But I’m glad you showed how to jump start as a first test of a battery’s health!

Thank you for sharing tips to revive batteries. I found it very helpful!

Wow, I'm glad I watched this. I have a bunch of new batteries that have been sitting around for years going dead. I am so glad I can revive them now that I'm able to use power tools again.

This is one of the most useful videos I have ever seen. Thanks for posting.

Nice tips, my addition would be to flatten your solid copper wire ends rather than forcing them in. Mechanically spread and damaged connector terminals inside the pack will also render it unusable in a much less fixable manner. It can overheat and melt the plastic around it in your battery pack and leave a burned pitted spot in your tool's contacts as well.

Outstanding video!!! I need to and will try this myself soon, LORD willing. Thank you!

The scissors trick is jankiest of solutions in the best way. Love it!

What a good and simple way of explaining how to revive these batteries! I am a retired electrical engineer and never gave this a thought. Keep up the good work!

Thank goodness I searched for "scissoring videos." This was helpful.

WOW!! What a simple yet brilliant video. Thank you!

Thanks for taking the time to share your knowledge

I did jumped the dewalt 18v xrp batterys according to your instructions for my dewalt 18v xrp batterys. And so far it worked. No errors on the charger. Time will tell. The 20v adapter puts every tool out of balance and too tall. And my problem is I purchased about 10 major 18v tools and really don't want to add an adapter. All my Dewalt 18v tools are still in their hard cases, most only used once. Thanks for the video.

Nice. We seem to replace a lot of B&D batteries for our weedeater(s) - I'm trying this next time!

Thank you for taking the time to do the step by step resurrecting of the battery

Just did mines and it's charging now great 👍 information thank you 👍😎

This is a brilliant idea. Thank you so much. Also, you've provided a very clear explanation of the situation and how to correct it. A breath of fresh air.

Wife likes all kinds of ambiance low power stuff around the house. I made her switch to rechargeable batteries due to how many she was going through. The problem with these devices is that they will suck a battery to 0. So i built a board to be able to jump-start them and get them to change easily. Works really well. I've also done this on car batteries, Zegway batteries, and many others threw the years. Never had an issue.

I have a brand new hammer drill with a bad battery that I purchased. I'm glad I kept it. Just saw your video and tried it out. It's currently charging. Thank you for sharing the trick.

WOW, It worked on my 18v Black & Decker dead battery. Fully charged and holds charge well. Thank you for the tip. Super.

I’ve done this with Ego56v batteries and it does work. I had a battery that wouldn’t take a charge and registered a fault, ran the wires like he showed and it gave the “bad” battery just enough charge for the charger to recognize it as a good battery in need of charging.

I've had this issue before. In the past, I've just left the battery in the charger, and sometimes, after a few hours, the battery starts taking a charge. Perhaps the charger recognized a slight charge during the process. Will use your tips, though - much easier!

Good video. Done this before and several times and it worked well. I've also jump these type batteries with car battery charger... but on low and just a quick hit!

Thank you for this new idea. Great reference 👌 to spark new style of thinking saving time & energy.

Tries it on a newer dead battery - worked like a champ !!!! thank you for the video

FYI - if batteries sit on the shelf unused they undergo a process called self-discharge. See wikipedia topic "battery self-discharge" for details. I have several Ryobi tools each with a battery and I rotate thru them so a battery doesn't sit unused for months on end. A lead-acid car battery can also self-discharge over time if left unused but also after years of use the chemistry degrades so they no longer hold much of a charge and need replacing. A table in the article notes lead-acid batteries self-discharge around 4-6% a month and eventually won't have enough charge to crank the engine. Lithium-Ion self-discharges 2-4% month and eventually won't have enough charge for the charger to recognize the battery as good. So the trick in this video seems like a good way to give a still-good battery a kick so the charger will charge it. But you will know if the battery is really degraded when it only runs the tool for a few minutes after "full" charging.

I fix my black and decker batteries with your video thank you!!!!

Excellent tip! Thank you very much.

Very helpful... any suggestion for a blinking charger and the battery isn't charging?

Ingenious! Love this! Thank you so much for the wonderful tip! Gonna save people some serious bucks!❤

Thanks for this tutorial, I tried it on my M18 red lithium, it sparked a little but all it took was less than a min and now its charging, this is awsome!!

I just tried your solution. It worked! Charging the DOA battery right now.

Great video. Great comment section. To avoid any kind of battery fire due to over charging or failure. Get your self a metal garden shed run a 120v GFCI circuit to it and make a charging and battery storage set-up insde it for your rechargeable battries. Locate it as far as possible from occupied structures garages and any flamable materials. Dont ask how I know... a thief leaves the coat hangars, fire leaves nothing... I'm a retired Electrical Contractor. ✌️🙏😇 Stay Safe. ❤

Very nice. Never would have thought of using scissors.

Hey. I tried this on a dewalt flex volt and it worked. You’ve saved me $200🤙 Thanks so much. Great video 🙏🏻

This was AWESOME!! Thanks SO MUCH for sharing this knowledge with us! This "hack" rebooted my completely dead DeWalt 20v battery.

Never had this condition before, but I have had the charger say the pack is bad a lot. But I gotta add that a current limited power supply would be a better choice for this. The dead battery could overheat and die from the potential short circuit current draw if the dead battery cell is defective.

Scissors is a neat idea. Variation on this works of phone batteries too, but very low voltage using a phone charger. The BMS battery management system on Lion batteries can't read a fully empty battery is why they won't charge and why this works. Better trick is to not leave them in place to lose charge, give them a check once in a while and a top up.

Thank you for sharing this it was the source of my temporary out of service battery back into action.... Thanks again for sharing your knowledge. Cheers....

Thanks for sharing. One of my 20v batteries crapped out a few months ago. Going to try to jump it tomorrow!

You can also use a spade connector for the 18v one

I've done this before but, although the batteries will then "charge", at least in my case, they were able to hold very little power.

Genius Mate, Thanks heaps 🤜🏻🤛🏻🕶🦘🇮🇹👍🏻

Perfect timing. I just had a 20v dewalt stop charging for some reason. Can’t wait to try this

While this does work, there is nothing to regulate the current when you connect the positive wire. There's always a chance with Lithium that you'll have a fire if you charge or discharge too rapidly. I recommend using a current limited bench power supply, or be ready to chuck the whole thing outside because it's on fire.

Just be very careful if with Li-Ion batteries if they have drained all the way down to zero volts, they can reverse polarity and if they do you will have a nice fire as you try and charge it.

Very useful and Excellent demonstration to revive dead batteries! I learned something today. Thank you.

This worked perfectly! Thank you SOOOO Much!

I've done this before. one way for the manufacturers to prevent this issue is to have a jumpstart button on their chargers. I suppose that would be counter profitable because they can't sell more batteries that way…

There's a lot of good knowledge on UKposts, with real peoples that can help all of us save money.😊

Bloody brilliant!

👍👍👍👍👍👍👍AWESOME!!! I'm so glad I watched your video. I have tossed "dead" batteries and almost tossed a $250 9.0AH Flexvolt 60V battery. I used this method to resurrect it and I couldn't be a happier camper ( I needed to flatten the wires i used with a hammer to make them fit). I connected them for 10 minutes just to be sure. Based on this I recommend not to connect for more than 3 min. They almost equilibrated and got pretty hot. That much charge that fast probably wasn't too good for the "dead" battery but it was certainly better than tossing it in the recycle bin. THANK YOU!!!!!!!!

Been doing this for years, however the dead battery doesn’t ever fully recharge or last as long as it should.

Thank you! I have wasted so much time cleaning contacts and bending them back and forth thinking it was a bad connection. Then wasted lots of money on new batteries. This video is going to save me a ton of time and money.

Fantastic info! I have several dead batteries that I am going to try this out on.

Great lesson! Thanks very much for sharing!

The 20v and 18v are actually the same voltage. They each have 5 cells in series. Normally the cells are specified by their nominal voltage of 3.7v so 5x is 18.5v. However at full charge the cells are at 4.2v, so 5x is 21v. But there isn't much capacity between 4.1 and 4.2v, and it is better for the usable lifetime of the battery to not charge it up all the way, so 20v is a nice round number pretty close to the typical upper limit.

In case you don't have a second battery to jump start the dead battery, I did the same thing using my car battery and a set of jumper cables. I had to clip a piece of wire onto one end of each jumper cable so I would have something small enough to fit into the grooves on the Dewalt battery. I used an old guitar string because I had one handy. I only jumpered them together for less than a minute. The 12-14 volt car battery shouldn't cause any harm to the 20V battery...and it didn't. I have used that rescued battery for about 2 years since then and never had to jump start it again.

Simple, cheap, and smart!! Thank you

I'm trying it on the Ryobi. Thanks, hope it works.

Beware - this trick can definitely work if the problem is that all cells have a too low voltage. However if all cells but one are good and one cell is dead short - which definitely commonly happens too - it's an easy way to start a fire. To prevent this, chargers for n-cell batteries tend to refuse to charge when the measured voltage is smaller than the fully charged voltage of (n-1) cells. Some chargers are more clever than this and look at the charge/discharge curve to detect this condition more reliably - these chargers will have better chances at reviving a dead battery. Thus, when doing this, best do it outdoors, with no flammable material nearby, and also thoroughly test the battery afterwards - either by fully charging, discharging and recharging once to see if it gets a good charge (on a single cell short you likely will have an "empty" - as in, too low voltage - battery soon after use again) or fully charging, discharging a bit (like a minute of power drilling into the air) and checking its voltage to see if it is near its design voltage (if it has a single cell short, it will go below design voltage very soon after charging and even drawing a small amount of energy from it).

Caution! Safety warning! (I add these here, because they are missing from the beginning of the video). The method presented here pose a significant risk of starting an unextinguishable fire, burning a hole through your workbench, burning your house down with chance of severe personal injury "Dead battery" can be caused by many things. All this works, if the problem is overdepletion and the charger does not want to start the charging detecting voltage below its safe limit. However, you can have many other issues: damaged cell, shorted cell, bad contact, or in case of lithium, a malfunctioning protection circuit. Sometimes the protection circuit is not even in the battery, but the tool and the charger. All these can result in pushing huge currents between two batteries with the risk of destroying both and causing injury and damage. If you want to do this safely, read up on battery chemistries and charging parameters, get a precision current limited power supply, properly disassemble the battery packs then analyze and charge each cell according to its specifications. Dear Uploader, I am sure that you mean well with this video and that as a former law enforcement officer, you don't want to put anyone at risk. Please add cautionary warnings, before someone uses this technique innaproriately and injures themselves or destroys something. Thank you, and wish you all a safe and creative new year!

I never know about this techniques, Thanks for the info

Awesome idea, have not had any batteries go dead yet but will now know what to do.

Dude, you need to mention that if the two scissors touch, you gd ot a dead short. The good battery could explode or catch fire. Somebody is gonna start a fire and sue you. You need a little safety disclaimer...lol

I got a bunch in my junk drawer. I will try this. Thanks you Sooooooo much.

Awesome it worked on my Ryobi 18v, thanks

Holy electrical safety Batman! If you don't have alligator clips, go buy some alligator clips!

Very good information. I wasn't aware that this was possible. Thanks for this.

A really valuable tip! Thank you for sharing.

Wow, just awesome, thank you.

Thank you 🙏 Sir for the great information given to the world to save money.

Amazing. Thank you so much for putting this video.

Thank you for the great tip.

Excellent Presentation. Thank you for sharing this money saving method.

Thanks for this video. Very helpful.

SOOO VERY cool. Thanx for the tips.

FANTASTICALLY WELL PRESENTED.

Very useful process- Thanks!