"Fixing" Li-ion Batteries that wont take a charge
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- čas přidán 8. 09. 2024
- Does your li-ion battery fail to charge in the charger? This DIY method shows how to wake dormant Li-ion cells above thier low threshold voltage allowing them to be charged normally. WARNING! Try at your own risk, these batteries can explode!
IT WORKED !!! Thanks. 300 thumbs down can only mean one thing: They blew themselves up when they touched their tongues to the battery.
genius
I feel grateful this reconditioning program czcams.com/users/postUgkxcJ22tnHH9l1vjdIdEIG27iOG55P7LXI8 was started. I had Three dead batteries scheduled for disposing of. Having said that, I tried out reconditioning them and it took me only an hour to do it! It doesn`t matter what type of battery you want, the process works.
@kristina, It really depends on what the max voltage of the batter is supposed to be. If this is supposed to be a 12VDC battery, then this seems fine. If its a 48VDC battery then depending on how many cells it seems bad.
Great video with emphasis on safety, but consider this for more details, especially for more current batt packs.
Sometime all that is required is repeatedly inserting the batt pack into charger until unit senses enough voltage to charge the pack, since the initial test provides a small charge, but this can take MULTIPLE insertions, so best to check pack voltage to see if close to 75% of rated voltage.
For a bit more advanced DIY viability test and resolution there are 2 significant considerations that may require additional advanced steps. Both require opening up the case, which can void any warranty as well as add more safety risk. This usually requires a special "safety" driver bit to remove the screws, one or more of which may be hidden under rubber seal or label.
1) If the source of failure is the circuit board or a non-battery component inside the pack, then NOTHING below will help.
2) But chances are there is one or more under-voltage 18650 Li-ion cells, which can be individually measured with a voltmeter once case is removed. If one or more is significantly measuring a lower voltage than the others (normal around 2-3.6V, below 1.5 V is either dead, deactivated by safety circuit, or hopefully just in "sleep" mode) which may be resolved by a trial of "boosting" the voltage with another 18650 or similar 3.5V power source, + to +,, - to -, for about 15-30 secs, small spark is OK. A confirmation of a potentially viable cell responding to a "wake up" is by showing any sustained voltage increase and eventually allowing it to be charged to 3.6V again. BE CAREFUL, and if voltage remains low or nothing, chances are it is not viable, either chemically or mechanically defective, possibly the safety circuit deactivated it, WHICH SHOULD NEVER BE MESSED WITH.
3) If a "boost" of one or more individual cell appears to be viable, the external "pack-boost" in this video may still not be effective as there may be components in newer commercial battery packs that prevents the inflow of power (transistors, MOFSET, etc ) using just the 2 external leads that may need a trial of being bypassed. To do this, find the part of the circuit board where the Neg and Pos aspects of the connected 18650 cells are making 1st contact. Measure voltage there and if still less than 75% of rated pack voltage, connect the charging source here (Again + to +, - to -) may confirm the bypass may be needed to provide charging of internal pack until smart charger detects an acceptable voltage and can provide complete charging , again a small spark is OK, but watch carefully.
Refer to czcams.com/video/p13iznXQNDg/video.html
If internal voltage is below 12 V, consider use of a low current 12V trickle charger to get to at least that voltage. Test voltage here every 15-20 secs if not using low current charge source, be aware of any thermal increase in both batteries. Success is indicated by sustained voltage increases measured internally, then also at the external connections, eventually to where the commercial charger indicates the pack is viable and completes charging.
If after trying these alternative reviving techniques you will either have a restored Battery Pack for either short or long time, or one to get properly discarded / recycled... or carefully harvest the parts for other uses.
Strongly recommend searching for similar videos, especially of the batt pack brand you use, and BE SAFE!!!!
I have a Hitachi 18v 1.5AH Tool battery with 0-.35volts measured anywhere with it apart. Is this likely a circuit board failure not allowing the cells to get any charge. There’s no sign of water or acid damage. No wires off. Are there usually any fuses? It has 5 Sanyo UR18650W cells. Thanks
Can confirm that inserting and removing the battery from the charger worked for me. I had to insert the battery over and over about 15 times before it starting charging from a "defective" state.
Be nice if we could actually see what you’re plugging in…
Thank you, thank you, thank you! I have an Hitachi 18v drill, which I hadn't used since getting a couple of Makitas, and one battery would not take charge. I checked the voltage on it and it was zero, whereas the good one was reading just over 20v. I did exactly what you did in the video and after paralleling up the two batteries for just a few seconds the 'dead' battery was reading 3.4 v and after a further 10 seconds it was up to 6.5v. I put it in the charger and it charged! Was reading 20.5v after finished charge. I have subscribed to your channel and look forward to some more useful tips and tricks. 😉
Worked for me. I had 2 Husqvarna BLi20 batteries (36v) that wouldn't charge. Each one reading about 5v. Hit them a few times from a DeWalt 18v until they read about 15v and now they're charging fine. Cheers mate.
Thank you for posting this - I just did this on a Stanley Fatmax 18v 2.0ah Li - ion battery that was refusing to charge - used a small 12volt to boost it from 1.8 v up to 9.2 - put it in the charger and it started to charge as normal - was about to order a replacement.
Really glad that this worked out for you! Thanks for watching.
Thanks for the info! I've got a 19.2 volt battery but nothing that matches, so now I'll try a 12 volt trickle charger and see if that works. 😊
Thank you! Thank you! Thank you! Not a drill battery but still a lithium ion. (In a very small vape actually). I'd accidentally put it in the washing machine 😐 so it wouldn't charge any more. I tested the voltage then gave it some short boosts using another vape battery. Got the voltage up from 3.01 to 3.23, testing the voltage every time I'd done a couple of boosts and it finally started charging when I hit 3.23. The vape cost me £40 and I'd put it in the washer and killed it so I bought another for £40 and did the same again so I was now £80 down. I've got one of them working again now so I'm super happy. I'll probably try this method on the other one as well now I know it works. Thank you again for posting this video! Anyone else reading this comment, be careful lithium Ion batteries can set on fire, I did mine outside just in case.
Thanks! I found a used drill and lithium battery at Goodwill. It was a $9 gamble. The battery was dead. I jump started the cells individually for a few seconds with a toy train transformer at 18.47 volts each and achieved 5+ volts total. The charger then could charge them and it works great. Thanks again!
Thanks to you & others like you that post these videos. You just saved me $230 on a new battery for my motorcycle. This worked like a charm. THANKS!!!!!!!!!!!!!!
Hi Don thanks for this video just done doing this procedure and it worked to my craftsman which been in storage for quite a time and now this a “success”!! again many thanks
Glad to hear it Ben.
can't it find a forum to post this, but seems everyone who has Husqvarna BLi20 batteries are experiencing charge problems. Here's a fix. if you can't charge the bli20 battery: unplug the POWER cord from the CHARGER. Also unplug the battery from the charger. This seems to reset the charge station when you plug everything back in so it works again. Must be a glitch in the charger's overload protections. Wish Husqvarna would help folks asking about this. This fix worked on both of my charge stations. all 4 of my batteries are charging again. WHOO HOO. Please Like this if it was helpful.
I didn't feel like getting my huge car battery charger out of storage to do the "trickle charge" option. I saw this video and I have to say that is a pretty slick way to do it. i did it the exact same way I used my charged lithium ion battery and it woke up my dead batteries. put them on the charger and they are good to go!! Thanks a lot for posting this version it works!!
Chris Merritt , glad it worked for you! Thanks for watching
I tried it but couldn't get the ion battery above 4.7 volts..I shocked it with a car battery,a trickle charger and tried hooking it up to a charged 19.2 v battery but nothing helped
Thanks so much, worked a treat on a SmartBro (LTE) battery ... able to fully charge now,
Thank you. I was getting tired of buying new Li-Ion power tool batteries every year, was beginning to think Li-Ion was just a scam and switch back to corded.
Thanks to your video it saves my 2 new but misplaced 2 years old M18 MILWAUKEE batteries been sitting in storage too long with only 3.4 & 3.2 volts back to normal.
I have tried by letting them charge over night each with failure, until I saw your video.
Tested and proven it's true.
Just want to say thanks. I recovered one that was dead... appreciate your video. Ps. Just elaborate on how you link wires in next vids..
Its a new invention of 21 century, now power problem solved and settelites will charge their batteries each other, its a memorable think in the world. Thanks.
I fixed two batteries with a computer power supply using the dc 5v output. Thank you!!!
Thank You for sharing your knowledge and carefully explaining your method. I used your advice to successfully revive one of my Kobalt 40v 4.0 Ah batteries.
Norelco Li shaver works the same way. Pull off the triple head. Starting at the tail end, pop the cases in half, slightly tricky to pop the four little retainers on each side with a precision screw driver, and charge the Li AA size directly with a small AA batt charger and jumpers. Reassemble the Norelco shaver and it should finish the charge in the 16 VDC stand with display indicating charge.
Man you just save me $130!! Had a battery that barely was used and found out it was dead when I went hunting (Ozonics 200). Found out it would't charge on the charger. Hooked it up to my car battery trickler and gave it two hits. Now it charges on the battery pack charger. U Da Man!
Glad that worked for you bud!
Great intro, great analysis, great theory explanation, great electrical technician skills...and you skipped right over the "pinouts" on the battery terminals! If you had pointed the camera DOWN toward the work, it might be easier. Patting the rounded side of the battery tower was not a really definitive way to indicate where the positive post is located. Is negative opposite? Take the 5 seconds to point to them, in camera frame.
Hey @gcflower99, You are completely correct. This was the first "DIY" video I shot. I used my cell phone clamped to a bench vise so production quality certainly suffered. I am currently building a new house so once the new shop is up and running I hope to have a better setup for nicer videos. Thanks for taking the time to watch and provide feedback!
I wish I'd seen this vid 2 weeks ago. My one and only big Li-Ion C3 battery (exact same battery as you show) was dead (the charge indicator light on the battery wouldn't even come on). So... I got 2 new ones off eBay (which work fine). I hated to just pitch the old one... then I saw your video. I "sparked" the old battery from one of the new ones and got it up to over 9V, then put it on the charger. It says it's charging AND the charge indicator now lights up when I push the button. I *THINK* it's going to work again. Will post an update with the end result. Thanks for the info.
UPDATE: NO JOY - After about 10-15 min on the charger - the charger lights looked like there was no battery at all. I think my battery is really, truly dead. But it was worth a shot. And I have 2 brand new batteries, so I'm back in business anyway.
Yep, sometimes they do die forever. Sorry this did not work out for you.
interesting points ,if anyone else trying to find out diy battery reconditioning try Cypouris Renewal Guide Coach ( search on google ) ? Ive heard some awesome things about it and my work buddy got great results with it.
Your way, sometimes it works, sometimes it doesn't.
When batteries really go that low, you don't know at what voltage they are inside the pack, or if you have a dead cell or even more than 1 inside the pack. I had packs with 3 dead cells inside. If you have a dead cell, you will overcharge the good cells.
To be on the safe side and not to damage any more cells, open the pack, check each cell for voltage, any dead cells replace them if you are able to, (obviously only if you know what you are doing) if they are at different voltages, you need to balance the lower voltage cells to the same voltage of the highest cell in the pack. Let it rest for a few minutes and then place it on the charger so the charger can do the work. Or simply fully charge every single cell separately.
I absolutely agree. As I prefaced the video with, I recommend exercising extreme caution. Thanks for your input and thanks for watching!
THX for the video. very helpful and concise
Thank you, just fixed my cordless circular saw 20v, due to this vid. Really grateful.
I tried it and it worked. Thanks... You are the man!!!
Thank you. Worked perfectly with video camera lithium ion batteries.👍🏾
Thank you Donnie. Just fixed a hard to find 4 amp battery.
Really glad to hear it!
I'm kind of dense - can you specify which tabs on the battery pack you're applying the voltage to? There are four. Thanks
There are 2 of then labeled + or -
OMG THANK YOU MAN!!!!! I'm trying to fix my laptop battery, it dose not even see it when charging. Thanks!!!
my goodness, thanks for this info, I have thrown away several batteries as I was not able to charge them anymore...thanks a million..
Just hooked up an old makita 20V lithium ion to my truck battery for about 30 seconds. Ended up with 7 volts and its actually charging now. We shall see 😁
What was the outcome? Did it last?
Lithium battery have a much less flat discharge curve than a NiCd or NiMH. Lithium batteries start at 4.2v and are discharged at around 2.8v and it is fairly linear. A 50% discharged cell puts out 3.6v.
With NiCD and NIMH, they start around 1.4v and very quickly drop to 1.2 and stay there until they are dead and drop off to below a volt. The wide voltage range of Lithium batteries are one of the major challenges they pose, not a strength.
I have a cell phone gimbal with a Li-ion battery and it was dead(3.7 volts), cut some old USB cable and and hit it with 5v, just 3 less than a second touch and voila!!! the battery is charging like brand new !!! SO IT WORKS!!! just be careful not extend the time or the voltage too much
thanks man this help me from sending back the whole kit I ordered from amazon with one bad pack that didn't wanna charge. Just use the other pack to jump start it and it worked in the charger with no problem!! thanks for the video!!
Thanks mate. Saved me the best Part of £250!
+Garry Davies Very glad to hear it!
Thanks for the info, seems to have worked. Except as stated, I needed to disassemble the housing and go directly to the batteries. Other than that, it worked perfect.
Great view of the grey wall of your workshop! Not so much of the charger.... have you tried this with larger LiFePO4 cells? (e.g. 40-60Ah) Use an Imax or Turnigy charger, they will safely charge most cells
Thanks! I think it's working on my Nextec Li ion that wouldn't do anything in its charger. I took a 12 volt battery and clipped to my voltmeter probes then probed the battery, the little 12 volt battery dropped to 9 volts (showing current flow, I then quickly stuck the dead li ion in its charger. The green light started blinking showing it to be charging. I also wore a face shield doing this. Update, 5 minutes later the charger was clicking then stopped. Tried to jump the battery again, same results. I also noted the battery was getting very warm. So I'm giving up on this one.
Thanks a lot for the tip I know I watched this video months ago but I forgot about it and it just worked on a dead lithium ion battery it's now charging after no luck for hours with the charger now it's working.
Thanks a lot, man, I just got two working, JumpStarted them as you do to a car battery, used car battery charger old school one 12V.
I\'m not sure but ,if anyone else wants to uncover how to recondition old batteries at home try t.co/uUSuy6Yk5g ? Ive heard some decent things about it and my mate got excellent results with it.
So the process is to zap the negative (of live) to negative (Dead) , while both positives (of live and dead) are connected?
or vice versa, Negatives are both connected, (live & dead) then zap the Positive of the dead battery?
It would help if you could keep your hands a little bit out of the way we could actually see what terminals you are putting jumper on.
Sorry about that. There are only 2 terminals on these particular cells. You can verify polarity by simply placing your multimeter on DC VOLTS and measuring voltages. If you have the correct polarity it will read a positive voltage, if you have them reversed it will display a negative voltage. Hope that helps!
Thank you used it to get a kobalt 80 volt battery for weed eater working
good vid will try on two Li-ion Makita batterys that are doing the exact same thing.
+Raul Romo Sounds good, let me know how it goes
Donnie... just bought a knock off 6ah cell, for my 19.2 Craftsman system... fully charged, new... runs strong... but seems to be dying early. Is there a basic test to see if it is REALLY a 6ah... and not a 3ah in a fake wrapper? Thanks!
Sorry what do you do ?
Positive to positive and negative to negative ?
Replacement battery pack for my bike which was sitting in the garage for couple years is a bit more than 500.00 US Dollars!
What I don't understand is that another video shows two identical batteries jumped together for 15mn to wake up the dead one. No spark, no hitting 3 times.
Does this mean that when using a higher voltage, you need to hit it only, while using the same external voltage you can leave it for 15mn ?
Thanks
Philippe; Thanks for your question. I am not sure to which video you are referring but here is my generic response to "battery-to-battery" CHARGING. These batteries are not designed to charge. They are designed to operate the device you have plugged them into unlike the mobile charging batteries that you can plug your phone, etc into for a quick convenient source of power.
If someone is using a drill battery to CHARGE another drill battery they risk an explosion or critical failure of one or both of the batteries. Unlike a wall charger or portable power bank (battery) your drill batteries do not have an internal circuit designed to regulate the flow of current as needed in a charge cycle.
The reason we are "touching three times" is so that we only flow a tiny amount of current back into the dead cell in order to raise the low cell(s) threshold voltage above the minimum required for the wall charger to recognize it as good and then take over the normal charging routine when plugged back in.
My battery was a Li-ion battery whose individual cell voltage was lower than what my charger would recognize as "good". Once I bumped this with a different battery the charger cell checks passed and charged the battery normally.
I hope this answers your question. Thanks for watching!
-DrCox
I actually tried that it goes to the whole sequence and then in like 30 seconds the green light comes on as to say it's charged but this still a red light on the battery when you pull it off the charger
Could someone tell me what of the 4 pins and in what configuration to connect the trickle charger? I apologize. i am very new to this. Thanks!
Yeah, the explanation wasn't clear at all. Positive to positive I think...
@@bobbyclemente21 Might be a temperature sensor for safety?
There seems to be a discovery that when the battery voltage falls below a limit the charger won’t recognize it, thereby making the battery useless. Can I use a 12V auto charger to bring the voltage up to where it can be recognized? Which terminal is positive and which is negative on the Hoover battery so that I can attach the positive clip to the correct side?
You have some nice tools.
I have a 18v dewalt lithium did exactly as you show on video put battery on charger and it shows that is fully charged but when i put it on drill nothing happens did i do something wrong do i need to leave battery on charger a longer time or is my battery just dead and need to replace it any info is welcome
So how did this work out long term?
By battery hasn't been used in a couple years and the voltage rating was less than 1 volt maybe even a half volt but once I jump started it it went up to 5 and then 10 after just a few seconds and now it's slowly charging
I am really appropriated,,,,,, really helpful
This gave me a idea with a pc power supply and a single cell battery and it work. It was reading 0.0v on the charger and after the first spark i plug it back to the charger and it read 1.0v and starting charging
Hello there. I have a couple of craftsman 19.2 volt lithium ion batteries and one of them is fine, however the other one measures at 4.7 volts so it can only make the led light on the drill come on when I press the trigger but when I put it on the charger the green light comes on and stays lit as if it was fully charged. I tried the method on your video, but to no avail. Any ideas? Thanks!
Hey Donniw Cox, i have a drone battery that has discharged, but there are 2 ports that lead to the battery. 1 2-pin port that powers the drone and a 4-pin port used for charging. which port do i plug into?
It worked. Thanks.
Glad to hear it! Thanks for watching.
it would be nice if you made it clear which prongs you are connecting to. otherwise, great video
I used another dewalt battery and jumped pos and neg small spark and now it charges
My 18v Porter Cable battery was defective ...When i plugged in into the charger it just flashed red indicating a bad battery. I tried this method of recovery, after doing so, the charger will no longer recognize the battery at all, so it completely shot now. I am sure this will work for some units but it didnt work for mine.
I did this with several power adapters at 12 volts then I did like you did with the 19 volt battery and I have no change in my voltage. What does it mean when you leave two batteries connected in parallel and the battery of lower voltage doesn't even change a tenth of a volt in 1 minute? I have the exact same batteries that you are showing in this video mine is at 7.28 volts - higher than your battery level and it registers nothing on the charger. Does my battery Behavior indicate that it is truly done and can't be resurrected from the dead?
It worked for me too, Thanks man!
this worked for me. thank you.
Any idea how to fix an sl161 batter booster that no longer holds charge
This totally worked!!
I did this, it worked but 2 days later, in a warm house both batteries are dead again. Thoughts?
I’m good following this video to test all the voltages but when he said hit it , once hit it twice and you can’t see where he’s touching on the battery, if he’s touching both negative and positive Or both on the same positive of the dead battery or what? Thanks for any info.
Hi and thanks for watching. I am momentarily bumping negative to negative, positive to positive.
That was my dog. Oh I thought it was a goat🤪
Ya didn't show or explain which terminals are positive and negative on the battery.
Just fix mine thank you man
elgoofy4 glad it worked for ya bud. Thanks for watching!
Worked for me!
Glad to hear it bud
any idea how to use this method on a 3s mini quad copter lipo?
K thanks
Here's how you can start a battery business at home and make a lot of money: JoxCharge. com
My battery is showing that it's dead but when I put it to charge it's saying that it's fully charge. What do I do to fix that? Will this method work?
What about these type of cells that will NOT hold a charge?
I bought a 48V lithium battery and only charge 30%, is there a way to make it charge up to 100%?
Did you manage to fix it?
DELAYED FIRE HAZARD for Lithium Ion (LIon) batteries!
Did anyone stop to ask - WHY did the battery pack shut down?
The battery pack was shut down as a safety precaution because LIon batteries used to catch fire. Then someone figured out why, and manufacturers started adding safety circuits to keep that from happening. What you are doing fools the safety circuit, and can lead to the battery pack catching fire:
- Once an individual (3V) cell gets below (IIRC) around 1.4V, the copper electrodes start to dissolve.
- If the pack is then recharged, the copper will form nucleation sites where metal whiskers will begin to grow (by electroplating), inside the cell.
- After some charge / discharge cycles, the metal whiskers will begin to short out the battery cells.
- Shorts in the battery cells can get hot enough to ignite the battery.
- Oops, left it on the carpet near the baby's crib!
LIon batteries hold a LOT of energy. They can catch fire and even explode, which will at least ruin any power tool they are in, and might start a house fire.
Better to get a new battery, or replace the old cells.
MrTechnophile
Well, this scares me off trying to get these two 40v going. They want $200 each for new ones and the whole lawnmower wasn't that much. Puh.
Did you end up trying it or not? $200 is a lot of money for a battery damm
Thanks for this
my problem is . the 2nd slot is always late when charging on my battery. ia there any problem with that?
Thanks Donnie, on it!
Great, let me know how it goes!
Put same battery on 2 amp 12v charger over night and didn't take any charge. I have a few of these. The craftsman charger says it's also a maintainer so left batteries on charger for weeks. Now they won't charge yet the batteries are like new
This method only fixes batteries that suffer from low TGV faults, sometimes caused by batteries stored for too long. Yours may be defective beyond what this method will fix. Sorry it didn't work for you, Nathaniel.
Donnie Cox after bypassing the board my lion red packs are working normally. I used harbor freight cheap float charger 12v 500 ma for 15 minutes brought pack voltage from 3v to 7v then normal craftsman charger worked. Thank you for your video!
Interesting. SO it charged, but doe sit last as long as a comparable battery that was good? Or does it die very quickly and need recharging again?
it's not "charging" the battery. it's raising the threshold voltage of the cells enough so your charger can recognize the battery and charge normally. don't leave the 2 batteries connected. risk of damage to the cells.
The Cells last just as long. My Li batteries are going on 7 years old now and are still pretty much as good as day 1 (the Nicad ones not so much). Remember, my battery was fine but had been sitting for a while in storage. This caused the ICV (Individual Cell Voltage) to drop below the limit where my charger would see it as a "bad" cell. The purpose of this video was to show that if you raise the ICV above the lower threshold limit, the charger will no longer see it as a bad battery and charge as normal. Obviously batteries will eventually die but in my case it was due to long term storage.
Donnie Cox how long in storage are you talking about? i have a bissel bolt vaccul with lithium ion battery and it wont charge, was gonna order news cells, theres 5 of them
hey, i repaired a few of these ryobi packs (5-cell and 10-cell) the voltage is is 20.7 at the cells before the circuit board and only 19.4-19.3 when check from the outside of the case, a few other battery packs will show 20.7 from outside .... any idea why its doing that ? Thanks
Lion cells have that circuit board that serves many purposes, My guess would be in your case you are reading ~20.7 before the voltage regulator and then outside the case is reading after the voltage regulator.
Mine shows its charging on charger but wont actually take the charge, just stays dead but charger shows it charging
You mentioned in your video "using a trickle charger" by that do you mean you can connect the charger to the output of the batteries and do what? Can you extrapolate?
Another video I watched used a battery "trickle charger" which uses low voltage/ amperage over a long period of time to slowly charge the batteries. You can get a 12vdc trickle charger at most automotive stores if you wanna go that route. I have not tried it myself.
@@donniecox9339 Does the connection of the battery output connect directly to the trickle charger leaving out the battery management board? Also, the 120 to 48VDC brick should also be disconnected?
@@MaxGoddur the battery that I was bumping only had a single positive and a single negative that I connected directly to. Did not bypass anything internal. Not sure how you're 48v battery is connected.
Side note.... I have a shunt implanted in my brain. They work great, until they don't 🚑
will this method work if I'm using regular nicad batteries to boost a dead lithium ion battery?
I was using a nicad battery as the booster as well. use caution.
I will let you know what happens when I'm done doing mine!
I've got an issue on a 40 volt Kobalt electric mower battery I'm trying to figure out why it won't take a charge
I followed the instructions and afterwards the pack had 20v and each cell was 4v, but the charger stays on red flashing, and the battery won't power any device. Problem is I never tested the cells before doing the refurb as per the video so maybe they weren't down below 1v. Anyone any ideas what might be wrong? The battery was powering a lamp for a long time and then it just went off so the battery should be exhausted.
Awesome! You da MAN!
Glad that it worked for you!
i dont have all your equipment- how can I do this ??
wiz b at a minimum get yourself a cheap volt meter and a voltage source at or near your dead battery voltage ( not above). you can get a sub 10 dollar meter at Wal-Mart or Amazon for like 10 bucks.
You dont want the cells to drop bellow 2.5v.. Thats the absolute lowest u want to go
If u go lower you will destroy the cells recharge cycle capabilities.. Also could start a fire.. Each cell should be 4.2v fully charged. Lith-ion chemistry like constant current and constant voltage to charge.. 4.2x5=21v fully charged
Wouldn't it be safer, and easier on both batteries, if you connected a power supply, or an ,40VDC wall wart, to partially charge the battery and then put in the charger?
Make that a 40V or less wall wart
What would I use to wake up my 40v lawnmower battery? They want $200 for a new one. I have two 'dead' ones. Help? They are 5 Ah btw
I tried a battery charger to get a spark to kinda jump start it so charger would charge but didn't work ?
Sorry to hear that. Sometimes the cells are just too far gone...
And, some smart battery chargers see the low voltage and fail. That's why the dumb battery or welder or power supply works it majic