i rebuild battery packs as a hobby. usually when the charger says it's full but it isnt is a very unbalanced cell. it needs opened up and each cell charged to an equal voltage, then put on charger. any set that wont go above 3v is not a good cell(s) and needs replaced with an equal capacity/internal resistance of the existing cells. for tool batteries i usually salvage from another dead battery to keep the brand and usage roughly the same if i can.
whats your take on these small buissness that are rebuilding car batteries at a fraction of a price? will they last as long as new ones? or you get what you paid for ?
@@mikeallen3646. It's hard to be the first customer but a reputable remanufacturing company is correct about the concept. Electric Cars should ALSO have swappable batteries (pull into a single car wash size building, robot swap the battery in the same amount of time as filling up a gasoline car) but they weren't interested in the maintenance, cost, etc.
@@arcanondrum6543 Tesla prior to its initial release actually had that as an option, swapping out the whole battery pack. For whatever reason it never came to fruition.
There’s one Chinese company which is doing that - it requires building the net of these service-points ofcourse which takes cost and time. I heard They’re trying this also in Europe, probably United Kingdom and also there was something similar in Sweden/netherlands I believe.
Good information. I have this issue after putting one of my batteries in my kids 4wheeler. It ran great for a while but won’t change. I tried to manually charge it but that didn’t work. It makes sense that Jerry rigging it into the four wheeler may have discharged one of the cells lower than the rest. I use to build battery packs when I raced RC cars, I’ll pull this one open and check the cells. I still have a bunch of hobby grade chargers, and one that will do lithium. Are these usually 18650’s
Elegant answer. Have had the same issue with a Greenworks battery and using what was at hand did it this way: Put a paper clip in the positive and one in the negative battery ports. Then using two low-voltage wires with alligator clips on each end attached a 12V battery tender to the Greenworks battery. This time connecting positive to positive and negative to negative. Plugged in the tender and let it run for 15-20 minutes and voilà the Greenworks battery charger will now recharge your battery. Best to avoid this situation by not running your battery so low before recharging.
That's what the battery bms system is for it's not supposed to let the voltage drop so low it can't charge. I've got a nearly new dewalt 60v bat at work thats like this, so I'm eager to try this tomorrow😊
Here's my method. Send the thing into MW using e-service. They provide a prepaid label. Then in about a week they'll send you a new one in the blister pack and everything. If you don't have proof of purchase they'll go by the manufacture date however in my exp, even if it's out of warranty, you're getting a new one.
Wow ! Please read up on lithium batteries and how there made , this is fooling no one yourself. That bms shut down that battery for a reason an most of the time but not always the cells are out balance, all it takes is one parallel cell or group to drop under 2.5volts to trigger the shutdown you can have all the other cells full at 4.2v but one group to low shuts it off because the charger will keep charging till top voltage is met that means some cells will over charge and that my friend is where lithium fires come from . So read more on how and why before you burn down your home or shop
@@debohannan4315 I'm not disputing that all I'm saying is send then back in. They are under warranty that's why you pay Milwaukee prices and not harbor freight prices
@@debohannan4315 I think you meant to leave this comment on the “main” comment thread and not this as a “reply” to this comment. I say that because, what this comment recommended was sending the old battery that won’t charge back to Milwaukee, which is the absolute best advice anyone could give in response to this video!!!
If you just used the battery and ran it for a long period sometimes the battery may be too hot internally to accept a charge, most all have a thermistor for overheat/low temp protection. After using a bettery its a good idea to set it out and let it cool or maybe even place it where it is a dry and cool place for 30 minutes to an hour and then try again to recharge it.
I noticed that most people stage their Milwaukee chargers backwards on their bench. The power cord is designed to be orientated towards the back wall and the indicator lights are supposed to be towards the front of your bench so that you can actually see when they're charged or not. Instead of the battery sliding on and off towards the wall it will slide towards you when you are using the charger. If you think about it most electronics with a cord are design to go out to the back and not towards the front of your desk or bench and that the cord would come out towards the direction of the plug that you're aiming to plug into. Thank for the video.
@@rossryder944 I would just turn it around and read the back like anything else. Its the shape that throws most people off probably. how often do people need to read instructions unless there is an issue? I usually just plug and play.
The problem is the internal Battery Management System (BMS) of the battery shutting down and not allowing the charger to charge the battery because the total voltage of the battery is Below a Safe level due to 1or more cells being low. By jumping the battery with a 2nd fully charged battery for a while... the low cells will be slightly high enough for the BMS to allow the charger to work,
@@theapocilip BMSs are there to protect against Lithium (Li-Po, Li-Ion) battery Overcharge and Under Discharge to protect the batteries. I have a $4K quadcopter that has BMS protected Li-Po Smart Batteries that discharge over a too long time.. When the batts discharge too low for the charger to recharge them, I force charge them to bring the batts back over the Minimum so the Balance Charger works properly. Discharging Li-Po batteries below or above their safe level can damage the batteries over time. Goggle is your friend....😉
Why isn't the BMS designed to allow the most-depleted cell(s) to recharge first... postponing the charging of any cells that have a higher voltage than the minimum cells have?
A spade terminal crimped on each end of a short wire works well also. Also if you need a DC source for a short time, the spade terminals work also. I have a bilge pump on a stick that is powered by. A 12 vdc dewalt drill battery. Continuing with this concept, there are battery holders that accept various tool batteries and have two wires coming out. Remote control builders use these for snap in battery capability.
@@austinbumbalough4307 Probably caused a big fire, as doing this is a fire hazard, and his phone burnt up in the fire and that’s why he hasn’t responded!!!
This video is one of several UA-cam shows that there is an issue with the BMS. While a good temporary solution, my experience with this issue is that there is an issue with cell balancing in the pack, when actually opening these packs and testing the voltage of each cell. There's an Australian tool testing channel that goes into the weeds of milwaukee packs. They clearly show that the bms boards of milwaukee packs have a big issue, and even the new forge battery boards also have bms issues. I think itbis high time to bundle these youtube videos and ask Milwaukee to do better and make better batteries with better bms boards and better universal connectors that can charge and discharge withoutbneeding two different connectors to charge and discharge.
I have a Makita 18v set that I bought in 2010. That set saw 5-6 days a week doing 8-10 hours per day of continuous use for just under 5 years, and periodic use since then. They still work. All the batteries still work. Only a charger has died, and that's because a re**** coworker set it on the polished steel finish machine top in the summer heat and fried it. They aren't the strongest cordless drills I've used, but I have dropped these things 30-35ft multiple times. They've been fully submerged in water, rusty water, mud, been rained on heavily during heavy use... you name it. They just keep going. In the last 5 years the company I work with has used only DeWalt and then swapped to only Milwaukee. The DeWalt ones were okay, but nothing particularly special and they were noticeably less durable than my Makita ones. The Milwaukee drills are strong. REALLY strong (for a battery drills)... but it's like working with a glass cannon. They're about as durable as styrofoam screws or corkwood nails. I routinely bring my personal Makita set to work on days I'm working alone.
One of my M18 batteries will only charge up to 3 bars on the battery, but NOT to the 4th red bar! Does anybody know how to fix that issue, please? Thanks for this video!
All you are doing is circumventing the testing circuit the charger does that would indicate to it that a cell may be bad or shorted. It is set up to not charge a pack under a certain threshold. Using any dc supply equivalent to the battery's output will achieve what you did. I worked for Snap-on Tools in the repair center here in Harrisburg for 20 years, and this is how the chargers work and this was the method we used for our shop batteries. lithium Ion packs use balance charging, so each cell has to charge and discharge at the same rate. One bad cell can drop the entire pack.
Nice hack! But I would have cleaned the contacts first then try the charger again before "marrying" them with the utility knife blades, just a thought.
@@diyhvacguy I did watch the whole video, but you didn't indicate if you tried to charge the battery again AFTER cleaning the contacts and BEFORE the knife blade trick, as you know, sometimes that's all it needs
@@GreyRockOne the average person is smart enough to put the pieces together, he showed that for example. That wasn't the issue always, the issue is that the battery management system isn't allowing the battery to charge for safety reasons
This is a problem only if you allow your battery to discharge completely under load or leave it sit too long. I have used this solution on AA rechargeables using paper clips. Most rechargeable batteries slowly self discharge so top them off occasionally.
While cleaning the contacts is important I'd be concerned about using sand paper. It's very aggressive and will likely remove the plating. Works short term but eventually will result in corrosion.
I'd splurge and buy a sheet of 3M Wet-or-Dry sandpaper. Instead of using cheap sand grit, the grit is bonded to the paper. If you get 800-2000 grit, that's so smooth you are just polishing, not scratching. You can get small assortments up to 3000 grit in auto body repair shops or aisles.
Just like your cell phone, you should never run your battery completely flat, this avoids a lot of issues with your battery. Cool hack with the razor blades, i've seen it before with wire from one cell to the other, but not the blades. Thanks..!!
While this CAN work, there is a reason the battery management system won't allow the battery to charge. Usually you have a bad cell in your pack. This will not address that. You may find that it charges but can't handle high loads, or dies in a fraction of the time it used to run a tool. Not sure how robust the safety circuitry is on these packs, but lithium cells do NOT handle over charging well AT ALL, with fiery, explosive results in some cases. Don't ask me how I know this...... You would be wise to send the pack in for replacement or to a battery shop for repair. A bad cell can be replaced with on of identical capacity, internal resistance and voltage for a permanent, proper repair.
3:10 - using sandpaper to clean each terminal. Why not FOLD the sandpaper over and clean both positive terminals at once and then do the same on the negative!!! BOOM… saved about 6 seconds.
My question is would you get the same effect if you cleaned off the bad battery and put it back on the charger as opposed to syncing up with another battery?
All you have to do is take some solid core Romex #12 strip it back about 1” then pound it on the ground on both ends then plug the batteries in together. If you have a vice then use it it pound it on both ends till they are flat
I had luck just put it back and forth on the battery charger cycle it like 10 to 20 times and eventually will take a start taking the charge especially if this just happened to the battery and it wasn't sitting for months. Here's what I think is happening when you put it on the battery charger and it's red it's sending a charge it's also checking the current so it turns green saying the battery is underpowered but in that little time that you're turning it red you're sending the charge and if you do it 10 to 20 times eventually it feels the current enough and starts charging.
It's my experience that Lithium Polymer (LiPo) batts have a default nominal voltage of 3.7V/cell and the typical batteries used in tools use Lithium Ion (Lion) at a nominal voltage of 3.6V/cell.
So, would any "dumb" source of low DC voltage work, if we don't have a healthy identical model battery? What's the range of voltages that could be used to "kick" the dead battery?
I've actually used a 12V car battery charger before to "jump" a dead drill battery and get it to start charging normally on its own charger. Wouldn't suggest anyone try this, but I did, and it worked.
Yes. Dumb DC voltage at or under the batteries rated voltage. Don't over volt them. Just enough to get the BMS over its low threshold should do it. It's not advertised what that low threshold is so this method is good. If you do use another source, just make sure you don't leave for an extended period.
@@zjan4me True. I should have clarified, in my statement above, that I only used that method by having one cable connected to the battery terminal, via a wire, and very quickly tapping the other clamp on the wire connected to the other battery terminal a few times. The idea that this was not a good idea and could possibly end badly was going thru my mind the entire time! LoL. Luckily, it didn't.
Just so it's under 20 volts it will work. Kinda depends on how long you want to sit there. I think with the method shown in this video, it doesn't matter too much if you leave it on for hours. There's not enough power in the other battery to "overcharge" the "dead" battery.
so i have this issue for craftsman 19.2 li-ion battery, but there are 4 connectors and it is not obvious which ones are positive and negative. Do I just need to connect them all?
I’m confused about this. I understand cleaning the terminals up with some Emery cloth for better connection, but I don’t understand what the good battery did to the bad battery 🤔 because it did not charge it ! So what did it actually do?
I have a Variable output DC power supply and patch cables. So should I put around 20VDC into my dead 18 volt Milwaukee battery? At what amperage rating?
It doesn't matter whether it's a razor blade or a very sharp pointed blade.The idea is to make the contact in which you can fool the computer to activate in charge mode .
Get 2 10inch pieces of 10gauge wire and 4 flat spade wire ends and use that to jump your batteries, throw those razor blades in the garbage or put them back on the coke mirror for later use.
Hmm I seen dewalt videos with the same trick bit they only connected the two for like 10 seconds. And when I did it the battery got worse lol. It would only charge one bar before and now won't charge at all.
The problem is most early Milwaukee lithium batteries had bad Samsung cells in them. They failed to charge evenly. You can open the pack and balance each parallel group. Put it back together and you're good. Most homeowners will never harm the BMS. It's just an unbalanced pack.
I wonder if there’s a time charging circuit in these batteries meaning after so many cycles it just says yeah no we’re done and then force you to go buy a new one
I know cheap cell phone batteries are like that. The BMS has a cycle counter, one cycle being below 10-20% and then over 90%. Once it reaches 25 cycles (or whatever) it reduces it's available total capacity by 5 or 10% (or whatever). I've taken old (old old) cell phone batteries, used a 18650 type charger (that had its own BMS protections, over volt, etc) and used those cell phone batteries on a bike headlight. Those batteries would charge up over 5 volts charging, then settle back to about 4.3 or 4.4. didn't have temp protection and and after the first time BOOM, I learned to put em under a cast iron pan, outside on the concrete. Only happened a couple times. Usually the "battery" itself was fine, the BMS had counted to many.
This is the very reason why I just buy a minimum of 6 batteries. If one stops working then I can simply send it in for replacement. I’m not worried about being down and out.
I have not had luck with this using the high output or forge batteries. It over heats wire or turns razor blades glowing red and melts the plastic casing around terminals….
I tried the battery jump on one of my Dewalt batteries several times and it didn't work. I had the battery in my Dewalt radio and it just quit, I checked the battery and it showed one light lit. So I put it on the charger and no charge. I have 2 other batteries and they're the same age with no problems. So there's definitely a different problem with that one battery.
One thing that I have experienced with my Milwaukee batteries from time to time I can put them on the charger and they will charge normally. Then again sometimes I can put one of them on the charger but for a second or two it’ll stay red like it’s charging and I go to walk away and it’ll start flashing red and green, like what does that mean?
This works…….sometimes. I’ve had that work and I’ve had it not work. I had one battery that you could do that for long enough that it would show two bars just from being hooked to another battery. It would run a tool. But if you put it on a charger it would not charge. Red and green light would blink back and forth.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
i rebuild battery packs as a hobby. usually when the charger says it's full but it isnt is a very unbalanced cell. it needs opened up and each cell charged to an equal voltage, then put on charger.
any set that wont go above 3v is not a good cell(s) and needs replaced with an equal capacity/internal resistance of the existing cells. for tool batteries i usually salvage from another dead battery to keep the brand and usage roughly the same if i can.
whats your take on these small buissness that are rebuilding car batteries at a fraction of a price? will they last as long as new ones? or you get what you paid for ?
@@mikeallen3646. It's hard to be the first customer but a reputable remanufacturing company is correct about the concept. Electric Cars should ALSO have swappable batteries (pull into a single car wash size building, robot swap the battery in the same amount of time as filling up a gasoline car) but they weren't interested in the maintenance, cost, etc.
@@arcanondrum6543 Tesla prior to its initial release actually had that as an option, swapping out the whole battery pack. For whatever reason it never came to fruition.
There’s one Chinese company which is doing that - it requires building the net of these service-points ofcourse which takes cost and time. I heard They’re trying this also in Europe, probably United Kingdom and also there was something similar in Sweden/netherlands I believe.
Good information. I have this issue after putting one of my batteries in my kids 4wheeler. It ran great for a while but won’t change. I tried to manually charge it but that didn’t work. It makes sense that Jerry rigging it into the four wheeler may have discharged one of the cells lower than the rest. I use to build battery packs when I raced RC cars, I’ll pull this one open and check the cells. I still have a bunch of hobby grade chargers, and one that will do lithium. Are these usually 18650’s
Elegant answer. Have had the same issue with a Greenworks battery and using what was at hand did it this way: Put a paper clip in the positive and one in the negative battery ports. Then using two low-voltage wires with alligator clips on each end attached a 12V battery tender to the Greenworks battery. This time connecting positive to positive and negative to negative. Plugged in the tender and let it run for 15-20 minutes and voilà the Greenworks battery charger will now recharge your battery. Best to avoid this situation by not running your battery so low before recharging.
This is basically doing the same thing.
Yes, absolutely the same idea. Shared it in case someone doesn’t have a second battery and that paper clips can be used instead of scraper blades.
That's what the battery bms system is for it's not supposed to let the voltage drop so low it can't charge. I've got a nearly new dewalt 60v bat at work thats like this, so I'm eager to try this tomorrow😊
Here's my method. Send the thing into MW using e-service. They provide a prepaid label. Then in about a week they'll send you a new one in the blister pack and everything. If you don't have proof of purchase they'll go by the manufacture date however in my exp, even if it's out of warranty, you're getting a new one.
Just what I needed tonight
Damn, I wish I knew this as well.
Wow ! Please read up on lithium batteries and how there made , this is fooling no one yourself. That bms shut down that battery for a reason an most of the time but not always the cells are out balance, all it takes is one parallel cell or group to drop under 2.5volts to trigger the shutdown you can have all the other cells full at 4.2v but one group to low shuts it off because the charger will keep charging till top voltage is met that means some cells will over charge and that my friend is where lithium fires come from . So read more on how and why before you burn down your home or shop
@@debohannan4315 I'm not disputing that all I'm saying is send then back in. They are under warranty that's why you pay Milwaukee prices and not harbor freight prices
@@debohannan4315
I think you meant to leave this comment on the “main” comment thread and not this as a “reply” to this comment. I say that because, what this comment recommended was sending the old battery that won’t charge back to Milwaukee, which is the absolute best advice anyone could give in response to this video!!!
Unbelievable. Had one of my Ozito batteries do this only 2 days ago. Thanks will be trying this after work today might save $60+
I love ❤ the razor blades idea for this. Thank you man 👍👍
If you just used the battery and ran it for a long period sometimes the battery may be too hot internally to accept a charge, most all have a thermistor for overheat/low temp protection. After using a bettery its a good idea to set it out and let it cool or maybe even place it where it is a dry and cool place for 30 minutes to an hour and then try again to recharge it.
I noticed that most people stage their Milwaukee chargers backwards on their bench. The power cord is designed to be orientated towards the back wall and the indicator lights are supposed to be towards the front of your bench so that you can actually see when they're charged or not. Instead of the battery sliding on and off towards the wall it will slide towards you when you are using the charger. If you think about it most electronics with a cord are design to go out to the back and not towards the front of your desk or bench and that the cord would come out towards the direction of the plug that you're aiming to plug into. Thank for the video.
But the printed instructions on the charger in this video would be upside down if the lights were facing front. Kinda goofy.
@@rossryder944 I would just turn it around and read the back like anything else. Its the shape that throws most people off probably. how often do people need to read instructions unless there is an issue? I usually just plug and play.
So what you're revealing is Milwaukees charger is a contradiction to itself
Look on the back. They’re meant to be mounted on the wall.
Thanks, that's a nice simple idea.
Yep contractor razor blades is the way I have been doing for a while, works great after few mins then to charger!! 🎉
The problem is the internal Battery Management System (BMS) of the battery shutting down and not allowing the charger to charge the battery because the total voltage of the battery is Below a Safe level due to 1or more cells being low. By jumping the battery with a 2nd fully charged battery for a while... the low cells will be slightly high enough for the BMS to allow the charger to work,
Interesting I did not know that. but what makes a low cell so not safe that they need this BMS safety system in place. Or is it just for more profit?
@@theapocilip BMSs are there to protect against Lithium (Li-Po, Li-Ion) battery Overcharge and Under Discharge to protect the batteries.
I have a $4K quadcopter that has BMS protected Li-Po Smart Batteries that discharge over a too long time.. When the batts discharge too low for the charger to recharge them, I force charge them to bring the batts back over the Minimum so the Balance Charger works properly. Discharging Li-Po batteries below or above their safe level can damage the batteries over time.
Goggle is your friend....😉
Why isn't the BMS designed to allow the most-depleted cell(s) to recharge first... postponing the charging of any cells that have a higher voltage than the minimum cells have?
@@brothermine2292 better ones have cell balancers to keep them all equal.
@@theapocilip
Lithium ion batteries are very dangerous without a BMS to control voltage.
"Amazing trick! Reviving dead power tool batteries this quickly is a game-changer. Thanks for sharing this valuable tip!"
How crazy my Dewalt battery happen to be like this 4hrs ago! I’ll try this in a few days! 🤞🙏Thank you!
Let us know either way please.
Great pro tip👍
This is a definite bookmark. Thanks.
A spade terminal crimped on each end of a short wire works well also. Also if you need a DC source for a short time, the spade terminals work also. I have a bilge pump on a stick that is powered by. A 12 vdc dewalt drill battery. Continuing with this concept, there are battery holders that accept various tool batteries and have two wires coming out. Remote control builders use these for snap in battery capability.
I will try this as i have 3 scrap batteries many thanks
Did it work?
@@austinbumbalough4307
Probably caused a big fire, as doing this is a fire hazard, and his phone burnt up in the fire and that’s why he hasn’t responded!!!
I have had 3 batteries give up the ghost the same way in the last year. Milwaukee replaced all three with no questions asked.
Seriously? Dewalt would never do that
Ryobi, either 😂.
Did you write them how did you go about asking them please
Cool 90-second video 😊
This video is one of several UA-cam shows that there is an issue with the BMS. While a good temporary solution, my experience with this issue is that there is an issue with cell balancing in the pack, when actually opening these packs and testing the voltage of each cell. There's an Australian tool testing channel that goes into the weeds of milwaukee packs. They clearly show that the bms boards of milwaukee packs have a big issue, and even the new forge battery boards also have bms issues. I think itbis high time to bundle these youtube videos and ask Milwaukee to do better and make better batteries with better bms boards and better universal connectors that can charge and discharge withoutbneeding two different connectors to charge and discharge.
planned obsolescence...consume...purchase more...consume...consume...purchase more.
@@quantumtechcrypto7080fuckin a! That's what it's all about man, we are a nation of consumers! Shopping is an addiction!
Rigid also !!
I concurr..
I have a Makita 18v set that I bought in 2010. That set saw 5-6 days a week doing 8-10 hours per day of continuous use for just under 5 years, and periodic use since then. They still work. All the batteries still work. Only a charger has died, and that's because a re**** coworker set it on the polished steel finish machine top in the summer heat and fried it. They aren't the strongest cordless drills I've used, but I have dropped these things 30-35ft multiple times. They've been fully submerged in water, rusty water, mud, been rained on heavily during heavy use... you name it. They just keep going.
In the last 5 years the company I work with has used only DeWalt and then swapped to only Milwaukee. The DeWalt ones were okay, but nothing particularly special and they were noticeably less durable than my Makita ones. The Milwaukee drills are strong. REALLY strong (for a battery drills)... but it's like working with a glass cannon. They're about as durable as styrofoam screws or corkwood nails. I routinely bring my personal Makita set to work on days I'm working alone.
One of my M18 batteries will only charge up to 3 bars on the battery, but NOT to the 4th red bar! Does anybody know how to fix that issue, please? Thanks for this video!
All you are doing is circumventing the testing circuit the charger does that would indicate to it that a cell may be bad or shorted. It is set up to not charge a pack under a certain threshold. Using any dc supply equivalent to the battery's output will achieve what you did. I worked for Snap-on Tools in the repair center here in Harrisburg for 20 years, and this is how the chargers work and this was the method we used for our shop batteries. lithium Ion packs use balance charging, so each cell has to charge and discharge at the same rate. One bad cell can drop the entire pack.
Nice hack! But I would have cleaned the contacts first then try the charger again before "marrying" them with the utility knife blades, just a thought.
You must have not watched the whole video haha we showed how to clean the contacts :)
@@diyhvacguy I did watch the whole video, but you didn't indicate if you tried to charge the battery again AFTER cleaning the contacts and BEFORE the knife blade trick, as you know, sometimes that's all it needs
@@GreyRockOne I understood your first comment.
@@canucanoe2861 uh..ok
@@GreyRockOne the average person is smart enough to put the pieces together, he showed that for example. That wasn't the issue always, the issue is that the battery management system isn't allowing the battery to charge for safety reasons
Thank you 😊
This is a problem only if you allow your battery to discharge completely under load or leave it sit too long. I have used this solution on AA rechargeables using paper clips. Most rechargeable batteries slowly self discharge so top them off occasionally.
While cleaning the contacts is important I'd be concerned about using sand paper. It's very aggressive and will likely remove the plating. Works short term but eventually will result in corrosion.
A Dollar bill will clean the contacts as well.
I'd splurge and buy a sheet of 3M Wet-or-Dry sandpaper. Instead of using cheap sand grit, the grit is bonded to the paper. If you get 800-2000 grit, that's so smooth you are just polishing, not scratching. You can get small assortments up to 3000 grit in auto body repair shops or aisles.
I agree. Don't use anything abrasive. Try thin card dipped in a solvent insted.
Great stuff, mine did this. Just went dead, I went into the shop to ask for a replacement battery, they said just buy a new one. 😮
Just like your cell phone, you should never run your battery completely flat, this avoids a lot of issues with your battery. Cool hack with the razor blades, i've seen it before with wire from one cell to the other, but not the blades. Thanks..!!
While this CAN work, there is a reason the battery management system won't allow the battery to charge. Usually you have a bad cell in your pack. This will not address that. You may find that it charges but can't handle high loads, or dies in a fraction of the time it used to run a tool. Not sure how robust the safety circuitry is on these packs, but lithium cells do NOT handle over charging well AT ALL, with fiery, explosive results in some cases. Don't ask me how I know this...... You would be wise to send the pack in for replacement or to a battery shop for repair. A bad cell can be replaced with on of identical capacity, internal resistance and voltage for a permanent, proper repair.
3:10 - using sandpaper to clean each terminal. Why not FOLD the sandpaper over and clean both positive terminals at once and then do the same on the negative!!! BOOM… saved about 6 seconds.
My question is would you get the same effect if you cleaned off the bad battery and put it back on the charger as opposed to syncing up with another battery?
What are the other methods you speak of if this doesn't work?
All you have to do is take some solid core Romex #12 strip it back about 1” then pound it on the ground on both ends then plug the batteries in together. If you have a vice then use it it pound it on both ends till they are flat
So you got 3 bars charged: does that mean it won't charge up to 4 bars? Or did you put it back on the charger and get it up to 4 bars?
I had luck just put it back and forth on the battery charger cycle it like 10 to 20 times and eventually will take a start taking the charge especially if this just happened to the battery and it wasn't sitting for months. Here's what I think is happening when you put it on the battery charger and it's red it's sending a charge it's also checking the current so it turns green saying the battery is underpowered but in that little time that you're turning it red you're sending the charge and if you do it 10 to 20 times eventually it feels the current enough and starts charging.
Very helpful!
I’m going to check my batteries now, thanks.
Aren't those battery packs full of the 3.7 volt batteries and is it usually a couple of those batteries that have low cells?
It's my experience that Lithium Polymer (LiPo) batts have a default nominal voltage of 3.7V/cell and the typical batteries used in tools use Lithium Ion (Lion) at a nominal voltage of 3.6V/cell.
Great Video! Thank-you! Instead of sand paper, use a thin nail file :)
Cool idea with the razor blades
Thanks. Best ever...
I Appreciate the info.
So, would any "dumb" source of low DC voltage work, if we don't have a healthy identical model battery? What's the range of voltages that could be used to "kick" the dead battery?
Was thinking the same thing. ie, some 18V DC power adapter
I've actually used a 12V car battery charger before to "jump" a dead drill battery and get it to start charging normally on its own charger. Wouldn't suggest anyone try this, but I did, and it worked.
Yes. Dumb DC voltage at or under the batteries rated voltage. Don't over volt them. Just enough to get the BMS over its low threshold should do it. It's not advertised what that low threshold is so this method is good. If you do use another source, just make sure you don't leave for an extended period.
@@zjan4me True. I should have clarified, in my statement above, that I only used that method by having one cable connected to the battery terminal, via a wire, and very quickly tapping the other clamp on the wire connected to the other battery terminal a few times. The idea that this was not a good idea and could possibly end badly was going thru my mind the entire time! LoL. Luckily, it didn't.
Just so it's under 20 volts it will work. Kinda depends on how long you want to sit there. I think with the method shown in this video, it doesn't matter too much if you leave it on for hours. There's not enough power in the other battery to "overcharge" the "dead" battery.
Good info THANKS
so i have this issue for craftsman 19.2 li-ion battery, but there are 4 connectors and it is not obvious which ones are positive and negative. Do I just need to connect them all?
It will be the outside ones, best way to tell is look at the pins two will be bigger
I’m confused about this. I understand cleaning the terminals up with some Emery cloth for better connection, but I don’t understand what the good battery did to the bad battery 🤔 because it did not charge it ! So what did it actually do?
I have a Variable output DC power supply and patch cables. So should I put around 20VDC into my dead 18 volt Milwaukee battery? At what amperage rating?
I. wonder if the idea works with blood transfusions.
AWESOME IDEA !!! THANK YOU.
Thanks !
I gotta try this I have plenty of batteries like this.
Thank you! 👍
I have a little battery like the pistol mag one that want even take a charge . Like the little battery in your video for any ideas
VERY KOOL BRO !...THX !
Thanks
It doesn't matter whether it's a razor blade or a very sharp pointed blade.The idea is to make the contact in which you can fool the computer to activate in charge mode .
Get 2 10inch pieces of 10gauge wire and 4 flat spade wire ends and use that to jump your batteries, throw those razor blades in the garbage or put them back on the coke mirror for later use.
Would this same process be followed for a 60 volt battery?
Awesome thank you!!
that works 10% of the time, it just happens again next time you try to charge it, a dead cell needs to be replaced not bandaged
Hmm I seen dewalt videos with the same trick bit they only connected the two for like 10 seconds. And when I did it the battery got worse lol. It would only charge one bar before and now won't charge at all.
Good ideas, ThanX.
The problem is most early Milwaukee lithium batteries had bad Samsung cells in them. They failed to charge evenly. You can open the pack and balance each parallel group. Put it back together and you're good. Most homeowners will never harm the BMS. It's just an unbalanced pack.
I would try contact cleaner rather than sandpaper to avoid future corrosion on the contacts
At 4:12 , this is how new batteries are made. LOL...
Also, clean with steel wool.
1:40 *Info starts here.*
Using razor blades... seems really easy to get cut bad.
Maybe it's better to use dulled razor blades... less likely to get slashed?😮
I have a m12 battery that won’t charge and has red and green lights flash on the charger and it sucks that it won’t change up anymore
I wonder if there’s a time charging circuit in these batteries meaning after so many cycles it just says yeah no we’re done and then force you to go buy a new one
I know cheap cell phone batteries are like that. The BMS has a cycle counter, one cycle being below 10-20% and then over 90%. Once it reaches 25 cycles (or whatever) it reduces it's available total capacity by 5 or 10% (or whatever). I've taken old (old old) cell phone batteries, used a 18650 type charger (that had its own BMS protections, over volt, etc) and used those cell phone batteries on a bike headlight. Those batteries would charge up over 5 volts charging, then settle back to about 4.3 or 4.4. didn't have temp protection and and after the first time BOOM, I learned to put em under a cast iron pan, outside on the concrete. Only happened a couple times. Usually the "battery" itself was fine, the BMS had counted to many.
i have 1 that the bms took a dump im using my rc car battery charger to charge it works good for me
that charger charges everything
What's the charger brand & model?
@n0buddy0 imax b6
Does this work with NiCad batteries?
This is the very reason why I just buy a minimum of 6 batteries. If one stops working then I can simply send it in for replacement. I’m not worried about being down and out.
Very cool
Planned Obsolescence at work
Remove the loose sandpaper grit from the contacts after cleaning them.
Can I mix battery brands?
The burning question, is will it go on to function normally after that, or is it on its last legs?
I have not had luck with this using the high output or forge batteries. It over heats wire or turns razor blades glowing red and melts the plastic casing around terminals….
Not only does it not fix a dead battery it makes your good battery bad at the same time what's not to love
open, check cells, recharge
Awesome!!!
That “junk” on the sandpaper is likely plastic shavings from the housing around the contacts.
I tried the battery jump on one of my Dewalt batteries several times and it didn't work. I had the battery in my Dewalt radio and it just quit, I checked the battery and it showed one light lit. So I put it on the charger and no charge. I have 2 other batteries and they're the same age with no problems. So there's definitely a different problem with that one battery.
What to do when 1 cell goes flat & the circuit puts it to sleep?
Mine doesn’t do anything when you press the button and blinks when on the charger. 😢
I have my charger setting in a metal cookie sheet, just incase 😢
One thing that I have experienced with my Milwaukee batteries from time to time I can put them on the charger and they will charge normally. Then again sometimes I can put one of them on the charger but for a second or two it’ll stay red like it’s charging and I go to walk away and it’ll start flashing red and green, like what does that mean?
Bad cell.
This works…….sometimes. I’ve had that work and I’ve had it not work. I had one battery that you could do that for long enough that it would show two bars just from being hooked to another battery. It would run a tool. But if you put it on a charger it would not charge. Red and green light would blink back and forth.
Hook a twelve volt bulb up to it and run it until the bulb goes completely out,than do this process again.
Great Hack!!!
You never use abrasive on terminal contact points, that ruins them.
Sure how long did it last
Good , muy Bien
This doesn't always work. I tried this method and it failed. I opened up the battery and noticed that one of the cells had leaked.
I wonder if you can do that with Ryobi batteries?
Absolutely
The Milwaukee 9ah batteries were problematic.
Interesting
You say it works for any brand, but can you use 1 brand battery to revive another brand battery?
If i only had two !
I find when this starts happening the battery loses charge a lot faster than when it was new
Same hacks as most YT videos, never work in our batteries, cell voltage were too low for it BMS to recognize the transfer