How I Fixed My Faulty Makita Battery

How I Fixed My Faulty Makita Battery
Products Used Amazon Links
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Makita Fast Charger - amzn.to/2APrzVa
Makita Twin Port Rapid Charger - amzn.to/2APkHr1
Makita 18V 3.0 Ah Li-ion Battery - amzn.to/2zJjbH8
Makita 18V 4.0 Ah Li-ion Battery - amzn.to/2E11822
Makita 18V 5.0 Ah Li-ion Battery - amzn.to/2E1c6of
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[@6GSF]

superb just rebooted my battery by connecting an external power supply at 10V 2A to + and -. Took about 1 min to get enough juice in it to then allow the charger to see it. This is so simple thanks so much. Significantly easier than rescuing a drone battery !

[@fidelguerraestenoz5714]

There's a safety chip inside de battery that breaks when the power goes bellow the limit, you have to dismantle the battery and bypass a safety chip by soldering a wire to fool the charger There's a video in spanish in KZbin that will teach you how to do it You just type in the browser "Como reparar una batería makita" You might need someone to translate But it's pretty simple you should be able to know what he is doing and how to do it even if you dont speaks spanish

[@Damaniac1964]

Definetely going this a try, have 3 "dead" batteries hoping to revive.. Loved your comments in the video, it was a pleasure watching.. Even if it doesn't work for me I had a good time watching ;) Cheers

[@P105Mews]

Any updates?

[@Damaniac0064]

@@P105Mews neh sadly not working on mine..

[@P105Mews]

@@Damaniac0064 bummer. I'll give my one a try and see how I go. It's a 1.3mah pack

[@harryberry474]

I know this is a old video but for those that have this issue, what happens is if the battery voltage gets too low there's a chip inside the battery (think of it as a fuse) that locks the battery and prevents it from being charged ever again. Battery voltage drops in batteries slowly when not in use and if you don't periodically charge these batteries and voltage drops too low the chip locks the battery. I would be curious if in this guys video if he used the battery that wouldn't charge and IF it charged as normal after doing what he did or IF the battery failed to charge again.

[@ScoobyRolla]

Hi Harry the battery was fine after that with no issues. But you are right there is a circuit board within the battery which monitor all the batteries in side. So if the batteries are leaking acid then it won’t let the charger recharge the batteries & the same again if the voltage is to low then it thinks there is problem with the batteries & again won’t charge it. That’s why if you are lucky & your batteries aren’t leaking acid & it’s low on voltage then usually this method will works. Hope this helps & thank you for sharing Harry

[@mbz4652]

Does that mean that it's not possible anymore to charge the dead battery or is there a solution?

[@moosaanwar7919]

Those chips on batteries are for overcharge and over discharge protection. Makita has its own battery circuitry built on BMS on charger, which includes faulty battery detection. And Makita XT battery pack itself has circuitry to prevent over discharge upon which the battery would stop working until recharged. So Makita chargers would deem any battery with lower than rated voltage as faulty. But what happens is sometimes batteries would gradually discharge even when it isn't in use. Over heating the tool due over loading could lead to sudden over discharge, which could cause Makita to detect as defective.

[@eddiebrandrick4374]

When you do this always start with a fully charged battery. If you don't you risk damaging your good battery by dropping the voltage too low.

[@jerrygould8]

good video, help save the waste. most chargers won't start if the voltage is too low, just make sure you keep them in sight when using jumpers as a really failed battery may short and can cause a fire.

[@ScoobyRolla]

Good point Jerry, thank you for sharing & thank you for watching to hope you are having a great day

[@Aussienessful]

Don't measure the batteries while the are connected together as you are only measuring the voltage drop across the wires which is created by the resistance in the wire.

[@ScoobyRolla]

Thanks for that 👍🏼

[@Aussienessful]

:)

[@robertmorin6495]

No. He is measuring battery voltage. There is very little voltage drop across a single jumper wire since the wire has close to zero ohms resistance. He is measuring the voltage between wire 1 and wire 2 which are connected to positive and negative terminals. For example, if he performed a resistance test on each wire when disconnected from the terminals it would show less than 1 ohm or close to zero resistance (unless it was broken), therefore no voltage drop occurs over the wire.

[@Aussienessful]

@@robertmorin6495 If you wanna get really technical, read Kirchhoff's voltage law. He is measuring the voltage of both batteries, the bad battery reads slightly lower due to losses though the connections because they aren't good enough to allow the full flow of current between the batteries. When you jump-start a car with cables sometimes not enough power gets through due to the weak connections to turn over the engine fast enough to start even though the donor car is fully charged and running. If you removed the cells inside the bad battery it would read almost the same as the good battery from the outside terminals while it it is connected to the good one.

[@antoniomacarena9060]

I TRIED BUT ... IS NOT WORKING

[@Ronaldo-cn2zd]

Scooby Doo!. 20 minutes all wired up worked a treat. Saved on a new battery. Kudos. Thanks and God bess

[@ScoobyRolla]

You are welcome, I’m so glad it worked for you & thank you for watching really appreciate it. Hope you having great weekend

[@meltonrobbo]

A bit long winded, but with fast forward an informative video. Useful.

[@ScoobyRolla]

thank you Paul appreciate it. I know it was a bit long winded but wanted to show everything. Thank you for watching hope you have a great day

[@I_keel_you]

I’m definitely trying this method tomorrow. Hope it works for me

[@filippocara0510]

is that battery still usable?

[@yovolvo9130]

Is not working. I kept the batteries connected for 3 h. Even is not discharging the good battery. Absolutely nothing happen

[@gregoryross.303]

My Makita impact drill battery would not charge, after being left flat for six months, and I tried fitting and removing it rapidly from the charger repeatedly in quick succession to 'reset the chip' but this did not work. So, after watching your video Scooby Rolla I did not have a second battery to use as you have done, so I used an old 16V, 0.5amp charger which I had lying around home from some unknown appliance or radio long gone from my home, and I stripped the two wires coming out of the charger and hooked them to the dead Makita battery for about an hour and then tried the battery in the charger. Bingo, the battery charged right up to full, and now I don't have to do anything further to it. Your video made me try this idea, and it worked. Thanks very much.

[@ScoobyRolla]

So I glad I could help & thank you for sharing your idea too

[@StevenVeldt]

Yes, fixed mine with this method. Thank you.

[@ScoobyRolla]

One of the lucky ones. Glad I could help & thank you for watching I really appreciate it

[@indefence7214]

Awesome! Thanks for sharing mate, just what I needed to know and will save me a few bob too! No I know this bit is going to sound bonkers but I've been meaning to learn how to use a multi meter for ages but never got round to it. Please could you share the make and model of the one that you used? Thanks in advance. All the best, Steve.

[@vsvnrg3263]

big clive did a good video about how to use a multimeter about a month ago.

[@ForzaLiverpool5]

if you want to know about multi meters you have to check out this old tony

[@kevinfoster2308]

Awesome I jumpered my Ryobi 3ah to it for about five minutes and bam 9.6 to 18 something volts. The reason for my voltage drop was years between charges while in storage. Charges now, thank you so much!

[@ScoobyRolla]

Hi Kevin, So glad it worked for you & thanks for watching really appreciate it.

[@mr.kenslifeshop4034]

My charger doesn't have those nice indication sounds

[@ScoobyRolla]

Hi Ken, watch this video it will show how to change your melody on your Makita charger & thank you for watching I really appreciate it. How To Change The Melody On A Makita Battery Charger kzbin.info/www/bejne/qKjEnpyFmNiXfc0

[@mr.kenslifeshop4034]

@@ScoobyRolla okay sounds good I will do that I didn't know that they all made sound my older one makes sound but the newer one I'm not sure it doesn't have the musical notes on it. I will definitely check that video out

[@mr.kenslifeshop4034]

@@ScoobyRolla so I have this Makita battery it's a 1.5 that I got off at eBay and it will not charge on charger but if I run it in tandem with another battery it will draw a charge off of the bigger battery and actually make a usable battery obviously I'm not going to do that to charge it risk my other batteries but I wonder what might be wrong with it?

[@joaobragag]

Friend - Congratulations on the video - My MAKITA DC18RA charger burst components and I don't know the code to buy - They are the IC PWM with 4 pins on one side and 3 pins on the other position IC-1 - And the other one is likely a transistor in position IC -4 which is close to the (smaller) TR2 transformer -------- IT WILL HELP A LOT TO KNOW THE CODES OF THESE TWO COMPONENTS SO THAT I CAN REPAIR THE CHARGER - I appreciate your attention - Thank you

[@allivanaip]

Good tip but too long! 1-3 words spoken is plenty. No need to say, I'm going to do this quickly.....just do it. Thank goodness for fast forward.

[@ScoobyRolla]

Sorry about that, appreciate the feedback back.

[@cwl206]

Thanks for the video but I think I'm gonna just recycle my 2 dead around 18 YO 18v batteries. Liked and subbed but this is one diy I shall pass lol

[@3018john]

Buy yourself a bench power supply,they are not expensive. A 30v-10A will help you out on many projects.

[@ScoobyRolla]

Hi, thank you, Appreciate the advice

[@vsvnrg3263]

i found a way that is easier for me. i run wires from a 20v nimh charger plugged into a timer set for 9 hours. i experimented bit by bit to work out the best way making sure nothing overheated. the nimh charger hasnt got the guts to overcharge and cook the 4ah battery. ive been using this system for 5 years. i always do it in a steel shed with a concrete floor so there is no fire risk. the makita chargers are happy with all my other batteries.

[@ScoobyRolla]

Thank you for sharing & I will give it a go next time. Thank you for watching I really appreciate it

[@大池夏彦]

ハイ!! スク―ビー、ご苦労様。　マキタBLは過放電になれば破損状態となり、その時期到来です。この方法が成功すれば世界的なマキタの技術は通用しない事を意味します。 単純に自動車バッテリーと同じと考えると間違いです。　経験済み、実証済みでした。 😆😆😆😆😆😆😆😆😆😆

[@valentinpopa765]

You shouldn't do that. The good battery will charge the bad one with tens of amps and will severely ruin the health of the discharged cells. You should open that battery and charge each group of cells with ~ 10mA and a progressive voltage until it reaches 2.7-3v. Then the charger shoud recognize it and charge

[@secondlife1970]

Yeah, that's the best way, I have made a video of that, restoring from 0.6V/ cell is possible. kzbin.info/www/bejne/mJTZl5KDjriAr8U

[@izzzzzz6]

Thats a good hack if the charge controller or fuse hasn't gone. But you shouldn't charge the battery that fast as it could damage it. You should use a power supply where the current can not get too large to damage the battery or a power supply that has variable current control to limit the current. This is especially important when the battery is dead. If the cells total less than 2.5V per cell you probably don't want to bother reviving (if li-ion) You can sometimes find completely dead cells in the pack and you need to swap these dead ones out to fix the battery.

[@ScoobyRolla]

Thanks for sharing izzzzz

[@knaptonmawson]

I tried this today the same as you. 14.4 v. I charged it slowly and got back up to 14.4 . Put it on the charger , did not work, tried it in the drill, did not work. My best guess is ,,,,,, The chip board , somehow the low voltage is recorded on the chipboard and it will register it dead even if you measure a good voltage. It's how they keep selling batteries . In another video I saw they changed the chipboard to get over the problem which I am now ordering from China at 4.50€.

[@ScoobyRolla]

Hi, If the circuit board is blown it will stops the battery charging up but if you’ve charged the battery & it’s not working in the drill it could be damaged batteries cells. Tell us know how you get on & good luck.

[@knaptonmawson]

@@ScoobyRolla yep, 4 cells where down, either 0 reading or less than 1 volt .

[@stephenmaas8775]

Do you have a link for the chipboard please x

[@montydaniels1054]

@Scooby Rolla. Hi, my battery only charges for about 1 minute then it stops charging... Have you heard that before? Great video btw....

[@davehawks8718]

Where can I find that wire you used to connect the batteries up?

[@gr2262]

You can make it yourself with any 12-15 gauge wire and male electrical connector ends. Very easy and surely found at harbor freight or walmart

[@WaveArsenal]

dont put the good battery on the bad one for a long time.. put in on for a minute and then recharge the good battery. That way you arent overheating the good battery or lowering its voltage too much. Also be very careful you dont hook positive to negative, as that would create a direct short and possibly a fire or explosion. Lithium ion batteries are nothing to trifle with!

[@ScoobyRolla]

Thank you sharing

[@WaveArsenal]

@@ScoobyRolla no problem. Just want people to be safe

[@Joseph-ib7hr]

Just send me again half point and I'm still having trouble. Can you please give me a hand pretty please pretty please to try to get this tool to work from. I don't know if to go out by Makita batteries or use the two batteries that I have try to do something with. I just don't know no more😊

[@keesverhagen9227]

Please next time. Leave the good battery on the charger until it is full. And then use it to charge the other one.

[@ScoobyRolla]

Thank you for the advice 👍🏼

[@linlyons1962]

This is DANGEROUS. You don't want to heat up a battery that much. You need a resistance in the circuit to limit the current. What's the cheapest, easiest resistance? An incandescent light bulb. Not an LED bulb. You want to put the light bulb (a resistor) in the circuit to limit the amount of electricity between the batteries. If you use a 25w incandescent bulb, that's rated about 40 ohms COLD, then you'd limit the current to 1/2 amp. That'd be good. I would use a 15w bulb, because I'm not absolutely sure about the cold resistance. (Lower wattage = higher resistance.) Keep in mind, the cold resistance is much less than that hot running resistance, so you cannot just do a calculation based on the listed wattage of the bulb that you use.

[@ScoobyRolla]

Thank you for sharing

[@linlyons1962]

I did some calculation, and a 100w bulb will allow maybe 1-3/4 amps, far lower than the battery put out when under load. that's what I actually used.

[@davidl.howser9707]

I used a solar panel and 14/2 gauge Romex Home wireing harness +/- to re-charge a previously bricked Makita 18 Volt Battery. Then the Makita Charger's micro processor agreed to charge the previously Bricked18 Volt Makita Battery to fully recharge thar Bricked 18 Volt Makita Battery. Then I used the previously Bricked 18 Volt Battery and was able to recharge the Makita 18 Volt Battery again :). Thank you !

[@dolmarf411]

it needs 12.5 v to charge. 2.5vx5 cells.

[@benjaminlussier]

No

[@Aussienessful]

Once a cell goes below around 2.0 volts the electrodes become plated with lithium and begin to break down. That battery has 2 parallel sets of 5 cells in series which means damage starts at 10 volts, so don't expect the bad one to perform as good as it did before. Plus that heat is from too much current flowing between the batteries.

[@ScoobyRolla]

Thank you for sharing that good to know.

[@TranTek]

The issue are both batteries are knock off / fake batteries

[@adamwuksta3255]

Good job scooby, i also have at least four of these makita batt packs that wont charge, some I haven’t even used in a tool before. I’m going to give this method a go. Thanks for taking the time to share your experience, i appreciate it.

[@ScoobyRolla]

Hi Adam, got my fingers crossed for you but I think it should work for you as your batteries are below the level to charge & doesn’t sound like damaged battery cells. thank you for the positive feedback & thank you for watching really appreciate it. Hope you are having a great day & it works for you

[@adamwuksta3255]

Scooby Rolla I managed to transfer a charge into the flat battery packs, even up to 18v but the charger still rejects them as I believe there is a built in circuit board that bricks them once they have been rejected by the charger a number of times. All the ones that are no good are 1.0 ah packs, both of the 3.0 ah packs I have haven’t given any problems. It has been an interesting experiment anyway, have a great day my friend.

[@vitalka555]

Worked for me. Revived 6amp battery with the 5 amp. Cheers mate. This video saved me 90 quid.

[@ScoobyRolla]

So glad I could help & thank you for the feedback. I think we are one of the lucky ones who didn’t have battery leaking acid or circuit board damage in the battery. Thank you for watching I really appreciate it. Hope you’re having a great day

[@shanesutton1996]

You have just saved me from buying 5 more batteries Thank you

[@ScoobyRolla]

Hi shane, Glad I could Help, 5 batteries that’s amazing mate 5 out of 5 you are definitely one of the luck ones. Thank you for watching really appreciate it. Hope you have a great day mate 👍🏼

[@daniel2064]

if you move faster the voltage on the bad battery will not have time to drop....Alternatively you can charge the bad battery by connecting the good battery in parallel and to the charger at the same time. Could have charged the bad battery in the time this video ran....

[@ScoobyRolla]

Good point Daniel. Thanks for sharing

[@Brad-0212]

You did well resetting it the thing you did wrong is keep putting it on and off you really needed another battery that had double the voltage in that battery to give it a good charge but glad it charged it enough to work 👍

[@jamesblack1011]

Sorry just seeing this video now. I have 2 batteries that take charge but it doesn't hold for long. Can they be revived? Thanks great upload.

[@ScoobyRolla]

Hi, James if they are charging but not holding charge for long time that means that battery cells leaking inside the battery casing or cells within battery are dying. Hope this helps

[@ScoobyRolla]

Best to sell them for cheap on eBay & replace them with new one because eventually they will not hold charge at all. Hope this helps

[@jamesblack1011]

@@ScoobyRolla yeah thanks for getting back to me I'll buy the adapter and a couple of lithium's I think haha. 👍🏻

[@hunterhryciuk8207]

so why the battery wont take a charge is because battery mangment system board thinks the battery gonna blow up but it wont all u need open it reset the board let stay on charger for few hours with 12 volts than reset board again throw it back on the charger and u will be fine after

[@williamblake8650]

How you reset board?

[@kalingsaroh3115]

I hav try a lot doing this it work for some time but problem do exist again try a lot and lot but situation is same not charging SO I UNPLUCKED IT FROM AC CONNECTION AND TRY CHARCHING WITH PURE SINE WAVE INVERTER 300WATT WAOH..! it goes smoothly charging no problem at all, i don't know the exact cause with AC line, may b due to low voltage or somthing else, U GUY TRY MY TECNIQUE MAY B IT COULD SOLVE YOUR PROBLEM.. do comment N like me if u find it satisfy.

[@wjwwkw]

it worked for me but after 3 mins it didnt work help

[@JamesSchubert-ei1km]

Good advice never gets old. I followed your video and revived two batteries from the grave. Thanks for making the video and for sharing.

[@ronlitz9055]

This video worked perfectly and was the most non invasive for me. Thanks for taking the time.

[@dellalderman8011]

I got mad at my 18 volt 6amp hour because it wouldn't take a charge. I slammed it twice on the concrete floor of my shop. Did not throw it down but wacked it really hard with it still in my hand, bottom of battery pack to the floor . Wack wack! Works just fine now. Been using it for at least 10 months now. Don't know what I did but it worked.

[@ScoobyRolla]

They do say if something doesn’t work give a wack a couple of times it might do the job 😂

[@chriss4365]

your method got my battery to 18volts but it still wont charge

[@ScoobyRolla]

Hi Chriss, if it’s back up to 18v and it won’t charge then it might be one or the other, the cells are leaking acid within the case or circuit board within case is blown which won’t allow the battery charger to charge. Sounds like the circuit board within is blown. I know some people have got a old laptop charger to use to charge the battery as it provides 18v to 20v but haven’t needed to it myself. But if your cells are leaking you can check it by leaving them for a bit and then checking the voltage if it losses all the charge then the are damaged within. Hope this helps

[@ScoobyRolla]

Another thing if you do use a laptop power lead Be very careful please. Make sure you connect wires first then plug it in. Playing on head. Hope this helps

[@donaldsaunders4736]

Unplug your charger and plug it back in 5 times fast👍

[@chriss4365]

@@donaldsaunders4736 the chip tells charger battery is bad. I ended up replacing a dead cell in the pack its good now but won't work on charger because of the chip.

[@19Daantje98]

Sadly, it won't always work this way. I have gotten 3 dead Makita batteries from a friend - after I told him I fixed one by replacing the dead cells - none of them will charge on the Makita fast charger DC18RC. 1 has a problem with it's temp sensor. The other 2 have a fault in their control board. As of writing this I have 2 Makita batteries connected + to + and - to -, the same as you :P

[@Joseph-ib7hr]

I have two batteries Makita batteries it. This is for a blower and it's called the funny name to it. I'll spell it. It's azivnia. They say a Makita battery will fit inside this blower and work fine. I'm not for sure because I haven't found a Makita battery yet. That works. Can you please help me out and find out what I'm doing wrong. I'm doing what you're saying but I just don't understand it. There's people like me just don't understand it. Please let me know when I can get back to you please. Sometime tomorrow I hope😊

[@chriss4365]

I just replaced the bad cell in my battery and it has over 20 volts again but the stupid charger wont accept it just like before because of that stupid chip

[@ScoobyRolla]

Well done replacing the bad cell. Yes thats the problems with the circuit board. You can replace the board

[@ryankislingbury9178]

Great video, thanks. Thought I'd lost myself 2 of the 4 5amp batteries I had 👌👌👌👌💯💯💯💯

[@eriksvendsen9858]

It's beter to use a power supply. 😎😎

[@brianwheway1933]

if you leave it on the charger, there is a fan which blows cool air around the battery if you leave it to charge it will cool it down. a lot of these batteries over heat and that fucks them up. inside the charger it has some fancy electronics in side wich monitors each cell, when they go faulty its possibly one of the cells that not up to scratch, it stops the charging due to a voltage/current imballance.

[@ScoobyRolla]

Thanks for sharing Brian 👍🏼

[@Ali-uv3dz]

you can fix it but to much ampere from good battery to bad battery in this case both battery early end of the life.

[@ScoobyRolla]

Thanks for sharing

[@peterrolex2349]

Why not buy a cheapo 18V 1.0 A transformer and use that rather than wreck your good battery. Maybe fine if its just that they battery is so low in charge the charger won’t recognise it. But!! One of our techies had this issue on a Sony laptop and slamed current at it. And it blew up! Very big bang! So be careful!

[@myname604]

This is happening to two of my batteries with all good cells. Even at 18.5v they refuse to be accepted by the charger. My 3 amp battery has no problem even when I drain dead.

[@illmatic33]

What if I use a battery (used to jump start car) and connect it to copper that makes contact with positive and negative, will it technically be doing the same thing?

[@samluna3778]

Should work. I shoved a couple of pennies in the tool connection slots in the battery, and hooked it to an automotive battery charger's clamps (12V). Doesn't have the safeties of a real lithium ion charger though, so don't leave home with it plugged in, and set it in relatively fire safe area. And don't mix up the polarity!

[@Joseph-ib7hr]

I don't have the money to go out and buy two batteries. It'll run for about 2 minutes if that and shut right off. I got a six-speed blower but they say Makita will work in that you're going to interchangeable but I haven't seen one yet. If any questions give me a call. I love Makita😮

[@krisd1000]

I jump charged mine and it went up to 16.8v untill one section was really hot so i actually had 2 bad cells. Mine is a Bl1830

[@ScoobyRolla]

Just be careful if they get to hot they can blow up.

[@Gkuljian]

Yay! I'm trying this right now.

[@srchecho2222]

Mine worked too... the dead one was at 13.5v and I've only left it for 5' until it got to 14.5v and the charger took it from there! Cheers

[@ScoobyRolla]

I’m so glad it for for you, one if the lucky ones. Thank you for watching I really appreciate it.

[@jerrymata1604]

i have a dewalt gharger and batt. plug it in and nothing my charger has a light on to let you no but thats not working either?

[@ScoobyRolla]

Hi Jerry try another battery on the charger to make sure it is working if it is then it could be that cells in battery are damaged & leaking on the battery what won’t charge. Hope this helps sorry about the delay in responding

[@chrisedwards7371]

it dont work I think a few volts went into bad battery but on the charger it started giving off a burning smell and started flashing red and green.the new battery when put on charger no burn smell but i do think a few volts went in because the test lights on old battery lit up brighter and after put on charger went off .go figure.

[@noanyobiseniss7462]

Needs charge so doesn't charge, sounds legit. FU MAKITA.

[@ScoobyRolla]

Now it’s crazy

[@BigWiLL_973]

I plugged my batteries straight to to wall outlet with two wires charged really quick

[@10000276249]

You should do that never with a full battery, the charging currents are way to high, try not to exceed 5A, so try more like 4-5V difference between both batteries or use a resistor like 0.47Ohms. after inserting the bad one 3 times into charger the PCB gets locked into faulty state, so if you try this you have to do it after first or 2. time the charger shows it faulty.

[@ScoobyRolla]

Thanks for sharing Stefan

[@stephenmaas8775]

My MAKITA BL1850 18V LXT 5.0AH battery wasnt charging, flashing red/green. I kept trying... I took it off and tried the the battery tester button and the battery started flashing 2dots red on the left half then 2dots red on the right half and back n fourth? do you think this method would work for me? My battery was on 2 bar before I tried charging it.

[@andriy-777]

Works perfect. Just connected the dead battery for 3 min and started to change again

[@ScoobyRolla]

i'm so glad it work for you andriy you are one of the lucky ones. thank you watching really appreciate it.

[@andriy-777]

@@ScoobyRolla Thank you again

[@zidi1982]

when you drained a good battery you should charge it up and then give the bad one a charge from the fully charged good one

[@ScoobyRolla]

Thanks for sharing

[@Johnny-bx7tb]

Does not work. Brought up the charge in the dead battery to 19.4 volts. It actually stopped charging from a new battery and it was not getting worm. Did this about 8 times for 10 minutes a time and would not charge. Power tool worked from battery to battery charging but the charger would not charge the dead battery. Sorry. Didn’t work for me. Good luck to all.

[@ScoobyRolla]

Could be two thing the batteries are leaking acid within or the circuit board has burn out the chip which monitors the battery cells & monitors when the batteries charge get to low & refuses to charge up. Thank you for sharing your experience & thank you for watching I really appreciate it.

[@chrismitchell6350]

Thanks for the video I’m up and running as a result of your time and efforts thanks so much Chris

[@jeremiasalexzander9838]

Instablaster

[@ragnarmarnikulasson3626]

how long did it last ?

[@ScoobyRolla]

Hi, Still working

[@ooltimu]

When you do this (battery to battery), you should also use a resistor. A large voltage difference like you have here will generate high currents. Best way to revive a dead battery is to recharge it at low current until it reaches the minimum voltage.

[@malcolmy11]

Resistor on both wires? How many ohms should we use?

[@ooltimu]

You can calculate the resistor by dividing the voltage difference by the desired charging current. So for example if you have a battery charged at 19V and one discharged at 11V and you want a charging current of 0.5 Amp, then you have (19V - 11V) / 0.5 A = 8V/0.5A = 16 ohms Be sure to use a proper power rated resistor. In this case P = U * I = 4 W One resistor on the positive wire will suffice.

[@lexluger9]

The wire being used to connect the two batteries provides a resistance

[@ooltimu]

@@lexluger9 I'll let you find out the resistance and the resulting current ;)

[@tvmasterprobutts4246]

Go back 2 the JATC training center....the V diff is not that great, current not that high, good to be cautious, but kinda a waste of time soldering a resistor in line.....just my .02$ worth of ohms law.....solid calcs though....

[@PatrickEArchuleta-fs8bv]

You have to leave the batteries longer Evan though you hear the buzzing it will adjust after 15 minutes.

[@combrogi]

Got my Makita battery up to 19v but it still makes the same noise on the charger and even though it's fully charged when I put it on a drill it only makes the light come on. Any ideas? 🤔

[@ScoobyRolla]

The worse thing is about the makita battery are that they have a circuit board inside the battery (1). Some times if the battery goes below a certain charge the board refuses to charge the battery. (2). & some times the battery cells leak acid on to them & damaged them so they refuse to charge up. I’m really sorry but it sounds like the board in the battery is damaged. I’m sorry I could help. Thanks for watching I really appreciate it.

[@ScoobyRolla]

It might be worth opening it up to see what’s happened to it or you could sell it on eBay as some people buy them & open them up & repair & sell them on. Hope this helps, might be better off selling it & putting some money on top & buying another.

[@combrogi]

Scooby Rolla Thanks for the reply. I see on other sites they say that if you put the battery on the charger and it fails to except it three times a chip or fuse on the circuit board blows or blocks it from charging again even if the batteries inside are ok. I have no fun to change the circuit board so will sell it on as the individual batteries inside must be ok. I only paid 10€ including postage so haven't lost anything.

[@frankieboyo1969]

After a few attempts at charging an undervoltaged battery the PCB will lock out the bad battery permanently.

[@kevinfetner7983]

I believe this is exactly what's happening to mine...it refuses charge from the charged battery. In another vid there is a link to buy the PCB for about $5. I'm not sure if I wanna go down that rabbit hole......maybe.

[@eliascruz9757]

Cruz ✝️. Buy a other 10 battery 🔋 like me.. lol 😂

[@ScoobyRolla]

😂 Better off but then battery are expensive

[@MrTangaroa]

Shot bro worked for me.. Lol. Took me 10mim to get my one going.. Haha. Left mine on until it got to 18v then put it on the charger didn't work 1st time I put it on but did second time.. Churr

[@ScoobyRolla]

Hi Richard, I’m so glad it worked for you. One of the lucky ones. Thanks for watching really appreciate it. Hope you are having a great day

[@y5mvbc]

Sounds good. I'm gonna try it out. I hooked it up already. I'm starting with a fully charged 5.0ah good battery and I'm trying to revive a bricked 3.0ah. If it works, I have 3 bad batteries to try out. I'm just going to wait 10 minutes at a time and recharge the 5.0 every 10 minutes as well. Wish me luck.

[@ScoobyRolla]

Good luck patrick

[@carpediemarts705]

Do tell?

[@osocarpinterocarpinteria]

Did work?

[@jaybird3225]

Only takes a few seconds just un connect them no point in checking voltage when the batteries are connected as they are now one

[@mikeoneill3212]

5 minutes topd 😂

[@raduan_alui]

Many thanks bro You helped me! Thanks

[@ScoobyRolla]

Glad I could help & thank you for watching

[@hulimarflores7589]

There are a few tips for fixing a car battery Don't try to do this until you know what you are doing - the acid can burn you check the voltage first - there may be a dead cell which would waste your time. Check the battery fluid. attempt to fully charge the battery. (I read about these and more on Jons mender guide site )

[@P105Mews]

Hey scooby great video. I've got a 1.3ah battery and have tried to bring it back to life as shown on your video. Voltage came up to 17.6V however it still can't charge. Is there anything else I can do or am I missing something? Side note : the battery hasn't been used nor charged in a few years

[@Brad-0212]

Hi you may need a battery that’s like a dewalt battery a 32v battery to give it a really good charge so the charger recognises it a 18v to 18v would take a while to give the power to it but if you double it using another battery with higher voltage the chances of it working are around 80% as it will give it more charge quicker hope this helps 👍

[@bogdandanut2605]

Can i use a good Ni Cd battery to revive a dead Lithium one? They both have the same voltage

[@richardgrocutt522]

Thanks for posting this video theses batteries are so expensive I brought a brand new drill with battery and battery wouldn’t charge I think it must have been sitting in a warehouse for ages thanks

[@blackboot28]

Both my batteries crapped out at the same time ? Got to be the charger.doesn't make sense.

[@ScoobyRolla]

Sad to hear that, nothing worse then both going at the same time. The batteries actually have a small circuit board inside them that some time causes the problem as the burnout.

[@hammershigh]

basically....

[@ScoobyRolla]

😂

[@vmontijo]

Thank you - I'm going to try this on mine!

[@ScoobyRolla]

Good luck 👍🏼& thank you for watching

[@utahprepper8925]

I have the opposite issue with my Makita battery. It's an 18 volt battery but the charger put 20 volts in it and now it won't run the tools. I'm trying to discharge it now to see if it will eventually work.

[@qldkev]

A full 18 volt battery is up to 21v. 5 batteries x 3.6 nominal = 18v, 5 batteries at 4.2v peak = 21v. So 20v is ok.

[@colinevans7134]

Your so right, I open up the battery and test every cell and see if there is a weak one and jump start the cell with another battery and I use a multimeter doing this, like the man said you can jump the battery by using another 18volt battery to give it more volts and then charge this and it works, PS buy a cheap multimeter and you can always check the battery for the volts. Good video and this video gives good explanation on how to do this thou 👍👏

[@ErnieSesameStreet]

How many year/month did the recover faulty battery work well again?

[@nunya7027]

Why wouldn't you charge up the "Good battery" all the way before trying to transfer the voltage to the other one? You were risking killing your good battery by not allowing it to fully charge every time you tried to transfer the voltage. You could have gotten to where you wanted to be in 1/8 the time.

[@ScoobyRolla]

The good battery was fully charged before I started as I said on the video but the faulty battery was taking a lot more power to charge back up so I worried. I didn’t want to damage the good battery by letting the power deplete completely on it so I was keeping an eye on it. Hope this helps explains

[@SuLorito]

I find it interesting that your charger sounds like it has a fan running but mine is silent. Yours also played a little tune at one point. I've never seen one that does that.

[@MrMarky2000]

Yours will play a tune too.. what you have to do is slide the battery in and out again twice quickly. It will then play a tune when full charged 👌

[@ScoobyRolla]

Hi, yes it has a built in fan to cool the battery down if it hot from using it while you are charging it & yes if you take battery in & out of the charger it will different music. I’ve done a video on this. Hope this helps & thank you for watching I really appreciate it.

[@ScoobyRolla]

Thank you for sharing & thank you for watching

[@Aussienessful]

Makita fast chargers have fans.

[@ScoobyRolla]

That’s right thank you for sharing

[@petes4927]

Should use a current limiting device like a 12v 25watt light bulb before one or both batteries burn

[@Warpedsmac]

Informative Thanks for uploading. Cheers from smoky Australia.

[@ScoobyRolla]

Thank you smoky & thank you for watching really appreciate it 👍🏼

[@nickfanthorpe8500]

This does work as I did it last week however I have to go through the same rigmarole every time I want to charge it so not much help in the scheme of things.

[@grahamrcurtis]

Worked like a charm after 10 minutes. Thanks for making the video.

[@ScoobyRolla]

Thanks curtis so glad I could help & really happy it worked for you. Thank you so much for the positive feedback & thank you for watching. Hope you are having a great day

[@illmatic33]

What did you use to bridge both batteries? I tried using a battery used to jump start car and that didn't work (used copper to connect positive and negative to respective terminals)

[@KennethCAdams-zc7zk]

Too long dude . Try hotwiring bad batt with an old Makita NIMH charger . I did last night . Went from flashing red/green will not charge 14volts to 19 volts in 30 minutes . Did not heat up at all. Will check again later today . keep you posted .

[@ScoobyRolla]

Nice one dude. Let us know cheers

[@KennethCAdams-zc7zk]

Put it back on the Nimh charger again for about 70 minutes . I did not mean to leave it that long but took the dogs for a walk . When i came back lion was not even getting warm , reached 19.5 volts on multi meter . Spun my drill the same as a brand new and fully charged 5.0 ah . I should mention that i have a defective Makita Nimh charger dc1804 . It does not trip off . just keeps charging. So that is my mule for charging the previously dead 3.0 Li-0n

[@ScoobyRolla]

Good news Kenneth, glad you have got it going dude. lucky to have a defective charger. Nice one for letting us know. Just a warning ⚠️ keep an eye 👁 on that charger as you know lithium ion Battery’s can be very dangerous as they can explode or catch fire 🔥. Good luck with any future projects.

[@KennethCAdams-zc7zk]

I should have hooked up a timer . Forgot it was charging , left it for 7 hours . No explosion or fire , cool as a cucumber but now only 15 volts max . Got it at the landfill for free but still sad .

[@ScoobyRolla]

Hi, Kenneth sounds like there’s a damaged cell in side leaking maybe. Sorry to hear that at least you got it for free dude

[@MsMad555]

In this way you will damage the good batery cells to much curent discharge withaut safty elektronik cose over hiting cells and separator will shot cell one four alltime and never resurekt in the future use old laptop charger if the mesure voltage aut for charger have more less 19-20v!!!!

[@ScoobyRolla]

+Krzysztof Pieróg Will Do Thank you

[@lordRW]

how did i not think of this... well i made my computer PSU charge the battery at 17v and 170ressistance (ca. 0.1amp) for about 2-3hours to bring it to a deacent charge, i still dont know if it will recharge as its only 14v still, and the battery is still not accepted, mit be a broken cell so the charger no longer accepts it.

[@ScoobyRolla]

+Lord RW Hi, Sorry about the delay in responding Sometimes you can blow the little circuit board with in the battery case and that’s why the battery charger does charge it or your battery’s could be leaking battery acid. Have a look at this video it might help. Recover makita battery. Hope this helps

[@Home_made_ch]

@@ScoobyRolla there no asid

[@CACIQUEHGC]

So useful, Thank you!

[@ScoobyRolla]

Thank you so glad I could help & thank you for watching really appreciate it, hope you’re having a great day stay safe