For quite some time I have been doing repairs/rebuilds on the 5 & 10 cell packs (Makita, DeWalt, etc). I was given a Kobalt lawn mower, 40v with a dead battery. I found two dead cells and two very weak cells. I had comparable batteries available...so to work I went. I spent several hours trying to get the end cap off (after removing the screws that hold both ends together). I was at wits-end. After looking at a lot of useless videos (which is usually the case) I came across yours. I fast forwarded till I saw where you removed the single screw that holds the end caps together on each half. WOW... I was so impressed with finding that, I went back and watched your entire video. Good stuff. Please know how much you helped me out. I will agree with your comment that Kobalt makes a well-built battery pack! Thank you again!
Those sanyo cells are junk. They over heat them selves all the time. I wish more manufacturers would stick with Samsung or Panasonics, even the new CJ sells from China are pretty good, better than sanyo's in my opinion
Recently popped one of these open & was like dang they really going to make it this easy to make a 4ah pack. Even if I don’t rebuild it for the Kobalt I’m going to save the holders for other projects, way too nice to just toss. All of the cells were roached, I think as 1p setup the tools must have just too high a discharge for the cells to last long, 2p should make for a much more reliable long lasting pack.
Great information!!!! So no need to change the BMS going from 2ah to 4ah. I have a few 2.5ah I want to go up to 5ah so they will last longer in my mower . Do you thing that will work? Thanks .
Bought a bad one at Goodwill to salvage cells from but all were bad. I don’t have any Kobalt tools so rebuilding it won’t do me any good. Would you like this shell/control board? Perhaps your coworker would like you to build him another 4AH pack.
hi, i think you are the best person to answer my question. You explain well and have a lot of experience. I have recently had fun restoring old power tool batteries. what always amazes me is that one or two defective 18650 cells and the battery is not functional. is there a way or modification for the batteries to degrade at the same time? I saw that there are active balance... would it be the solution? Sorry for my english im better in french 😀👍😀
That is the goal for sure. Some packs have BMS boards that help keep cells balanced and basically all packs are assembled with tested and matched sets of cells and the goal is that they would all last about the same. Unfortunately that is the problem, almost always one or more cells lose capacity before the others and it of course makes the whole pack unusable. I really don't know what can be done better until we get away from the lithium and get a better chemistry or possible solid state batteries that hopefully do not have the same issues as lithium. They are so temperamental, but they have great energy density. They are just such a pain to keep going.
Hi, great video. I have an 80v that all the cells test 3.78 - 3.83. charge indicator shows 2 lights, but it won't charge. When put in the blower it runs for 1 second then shuts off, after a brief time, it will do the same thing. I can't figure out what's going on. Any thoughts?
So the fuse is good and the power is getting all the way out to the terminals? If so, does the board have a programming header that could possibly have a test point? If you are unfamiliar with that I did reset a ECHO 58V battery in one of my older repair videos. If it has a reset pad on the board, I would try that. Thanks for your kind comment!
I have only had one fail and I had the other pack with all bad cells so I have not had to source one myself. I only worked on a few of these for friends. I would look into some like these and see if they will work. You may have to cut/modify the tabs a little? Unsure, but maybe this is a good place to start... amzn.to/3P3WKlG Or amzn.to/3L3G6S4
I really enjoy your videos and your thought, trouble shooting process, I allways learn something new and like Scott Bakula says on CSI New Orleans "Let's go learn things".
Thank you for the video, it's helped me take mine apart and somewhat understand what's going in there. However when checking my cells they seem to be okay. I have a 5 amp hour pack and so the way they're wired I can only measure two of them that are together. When I measure each set of two, they're all very consistent at about 7.6v. Before I took it apart it would charge up to 2 bars and then the charger would start flashing red. Any ideas? I guess if I un-solder the cells I can check them individually.
They are together in the 5Ah, but 2P or 2 in parallel so it will still be voltage of one cell for example 2.8 - 4V. You will know if one is bad because it will also affect the other one in parallel with it.
@@ThriftyToolShed thank you! So actually I think my cells are okay then. Any other ideas as to why I'm only seeing too bars before the red blinking starts?
@@BruceChastain I have not seen this exact issue with these packs as I have only worked on a couple of them now. I imagine you have verified the fuse is good. I would check that all balance leads measure correctly all the way to the board and if all else fails you can see if it's a microcontroller on the board to do a reset on possibly. I have shown that on a couple of other brand packs over the years. Some Ryobi, Ridgid and 58V ECHO packs have a header plainly marked and I jumped rst to gnd if you happen to see that. That is all else I would know to check from here...
Great video thanks and I did order one of those little spot welders and polymer battery, that beats the hick out of my soldering jobs thanks for the info
Awesome. If you don't already have some XT-60 connectors or leads you may want to get some to make the connection to the board easier. If I remember correctly it comes with ring terminal leads so I made up some cheap XT-60 leads for it. Thanks for your kind comment!
These were cells I had in a scooter battery not being used so basically new cells. Not any that I bought for this video. I mention in several videos and show using cells I get from 18650batterystore.com. I look at the Deals tab and usually see if they have a really good deal on some very similar cells and sometimes you can get them for half price. This is an example of some similar cells I would use if purchasing some for this example of a pack. If you would rather have the name brand cells, they have some of those on sale also. www.18650batterystore.com/products/eve-20p
I was looking for information on Kobalt 40V batteries and came across your channel, this has to be one of the best videos on TH-cam about lithium batteries, thank you very much for sharing such great material. Have you ever come across a Kobalt battery pack that flashes red on the charger but all cells look ok and have about the same voltage? I have one fairly new 40V 4Ah pack where all cells are presently showing around 3.98V but the gauge on top only shows two leds, and now the charger only flashes red when I plug it in. Is there any other test I can try without fully dismantling the battery pack? Or could it be the BMS itself that failed?
Thanks for your kind comment. I have only worked on a couple of these packs and have not seen that myself. I would think it is a problem with the BMS. If the overall voltage is good at the terminals, I would say that most likely points to the BMS board. The last thing to try might be to see if a reset is on the board. The board might be potted and make that nearly impossible on some. Some BMS boards have a spot like programming header, and jumping reset to ground can sometimes reset the microcontroller and can work sometimes. It's a long shot, but I have a couple older videos that it did help. I shared this on an ECHO 58V pack repair and a Ridgid pack repair video. It is the only thing left to try that I can think of. Best of luck to ya!
@@ThriftyToolShed Yeah mine is indeed potted, I also have a good working battery which is also potted so at some point I caught myself looking at still frames in your videos trying to identify such test points in the BMS PCB 😅 But I don't want to disassemble the good one and risk finishing with neither working afterwards. Guess I'll end up purchasing another battery pack and I'll later upcycle these cells on other projects. Thank you again for the excellent content!
The orange cells you are using as replacement from hover craft battery are not suiteable for kobalt battery as they use high discharge li ion sanyo rx 18650 with 20A continues discharge rate while one you are using dont have high discharge concequently battery will die again once you put load on this kobalt lawn mover using this battery from orange chinese cells.
It's actually working perfectly still today as it's only for a string trimmer and I tested it fully. I am aware of the cells. It also kept a battery from being useless to working better than the 1P pack from the factory for 2 years now. Other than that you are correct. Thanks for your comment!
These are 2 close to the ones I use on AliExpress. www.aliexpress.us/item/3256807162493370.html?spm=a2g0n.productlist.0.0.1fdb6c06S5ZQV5&browser_id=c53d1709d1084d4d9a9316b354719e5c&aff_platform=msite&m_page_id=caakhnpiwcawxyuu190d8017b5ce0eeae5314f361e&gclid=&pdp_npi=4%40dis%21USD%2133.83%2116.91%21%21%21245.00%21122.50%21%40210324f117216112544314907eecaa%2112000040365948985%21sea%21US%210%21AB&algo_pvid=681289c5-13e0-470d-a2db-4b2f1c825959&search_p4p_id=202407211820545451004439392500003500696_3 And www.aliexpress.us/item/3256807092772157.html?spm=a2g0n.productlist.0.0.1fdb6c06I0cjjw&browser_id=c53d1709d1084d4d9a9316b354719e5c&aff_platform=msite&m_page_id=caakhnpiwcawxyuu190d8017b5ce0eeae5314f361e&gclid=&pdp_npi=4%40dis%21USD%2132.86%2124.64%21%21%2132.86%2124.64%21%402103011617216112234858127ed04e%2112000040045495998%21sea%21US%210%21AB&algo_pvid=154a966b-ae94-495d-8738-251bf60e49a3&search_p4p_id=202407211820232773531632103450003333381_1
What does the ohm symbol connection do? I'm trying to run a kobalt mower off of a different 40v pack and it's not working. Does it need a resister to neg terminal. I tried to watch this video and take a closer look at the board but it's hard to tell. Thanks
It is marked as "COM" on the board and it is the white wire that goes from the connector board to the battery monitoring board. I briefly showed the white wire on the very basic drawing I shared of the wiring. I did not share much about it since I did not need to for this repair. I have not had the potting off the monitoring board to know for sure what the 2 center connections do. I would think the COM is more of communication between the pack and tool and possibly pack and charger, but not 100% sure. Some packs need a NTC or resistor to give a feedback for temperature to work, but I think this is much more. These Kobalt power tools and packs are made by Chervon that makes EGO, Flex and SKIL. I have spent time trying to figure out the D-Terminal on the EGO packs that are similar and uses communication between the microcontrollers so it gets complicated when you have no schematics or any information on these except what we figure out on our own. Hope it helps some. Best of luck to ya!
Thank you for the information. My mower has three wires only and I tried the resister to simulate a temp but wasn't sure exactly what it needed. It's the connector closest to the neg. The other connector I think is the comm one isn't used but I may not be looking at it right as I don't have a kobalt battery.
You do such clean work, and you're great at explaining your process! Please keep the videos coming
Thank you so much for your kind comment!
For quite some time I have been doing repairs/rebuilds on the 5 & 10 cell packs (Makita, DeWalt, etc). I was given a Kobalt lawn mower, 40v with a dead battery. I found two dead cells and two very weak cells. I had comparable batteries available...so to work I went. I spent several hours trying to get the end cap off (after removing the screws that hold both ends together). I was at wits-end. After looking at a lot of useless videos (which is usually the case) I came across yours. I fast forwarded till I saw where you removed the single screw that holds the end caps together on each half. WOW...
I was so impressed with finding that, I went back and watched your entire video. Good stuff. Please know how much you helped me out. I will agree with your comment that Kobalt makes a well-built battery pack! Thank you again!
Awesome! So glad it helped. Thanks for your kind comment and also watching the whole video!
Awesome clear explanation and useful pointers! His videos also double as ASMR! I greatly appreciate the fact that you are a gentle soul! ✌👍
Thanks so much for your kind comment!
Great video! Thanks for being so detailed and very cool to help out a neighbor!
Good sounds great view battery box. 👍
Great job 🙏👍🙏👍
Those sanyo cells are junk. They over heat them selves all the time. I wish more manufacturers would stick with Samsung or Panasonics, even the new CJ sells from China are pretty good, better than sanyo's in my opinion
Thank you great video
Recently popped one of these open & was like dang they really going to make it this easy to make a 4ah pack. Even if I don’t rebuild it for the Kobalt I’m going to save the holders for other projects, way too nice to just toss. All of the cells were roached, I think as 1p setup the tools must have just too high a discharge for the cells to last long, 2p should make for a much more reliable long lasting pack.
Great information!!!! So no need to change the BMS going from 2ah to 4ah. I have a few 2.5ah I want to go up to 5ah so they will last longer in my mower . Do you thing that will work? Thanks .
I don't know if the 2.5Ah and 5Ah are set up the same, but I would think so. Thanks for your kind comment!
@@ThriftyToolShed They look the same I will give one a try and see what happens. Thanks
Bought a bad one at Goodwill to salvage cells from but all were bad. I don’t have any Kobalt tools so rebuilding it won’t do me any good. Would you like this shell/control board? Perhaps your coworker would like you to build him another 4AH pack.
Sure if you have no use for it that would be great.
thriftytoolshed@gmail.com
hi, i think you are the best person to answer my question. You explain well and have a lot of experience. I have recently had fun restoring old power tool batteries. what always amazes me is that one or two defective 18650 cells and the battery is not functional. is there a way or modification for the batteries to degrade at the same time? I saw that there are active balance... would it be the solution?
Sorry for my english im better in french 😀👍😀
That is the goal for sure. Some packs have BMS boards that help keep cells balanced and basically all packs are assembled with tested and matched sets of cells and the goal is that they would all last about the same. Unfortunately that is the problem, almost always one or more cells lose capacity before the others and it of course makes the whole pack unusable. I really don't know what can be done better until we get away from the lithium and get a better chemistry or possible solid state batteries that hopefully do not have the same issues as lithium. They are so temperamental, but they have great energy density. They are just such a pain to keep going.
Hi, great video. I have an 80v that all the cells test 3.78 - 3.83. charge indicator shows 2 lights, but it won't charge. When put in the blower it runs for 1 second then shuts off, after a brief time, it will do the same thing. I can't figure out what's going on. Any thoughts?
So the fuse is good and the power is getting all the way out to the terminals? If so, does the board have a programming header that could possibly have a test point? If you are unfamiliar with that I did reset a ECHO 58V battery in one of my older repair videos. If it has a reset pad on the board, I would try that. Thanks for your kind comment!
What is your source for the 60 amp fuse for the Kobalt packs?
I have only had one fail and I had the other pack with all bad cells so I have not had to source one myself. I only worked on a few of these for friends.
I would look into some like these and see if they will work. You may have to cut/modify the tabs a little? Unsure, but maybe this is a good place to start...
amzn.to/3P3WKlG
Or
amzn.to/3L3G6S4
thanks@@ThriftyToolShed
Thank you for sharing this video
bummer it takes 6 weeks before spot welder ships.
Wow, even as an Amazon seller? Mine did not take that long that is crazy to me.
@@ThriftyToolShed finally got it prime, works great
cool I like the welder.
I really enjoy your videos and your thought, trouble shooting process, I allways learn something new and like Scott Bakula says on CSI New Orleans "Let's go learn things".
I am so glad. Thanks for your kind comment!
Nice job, I learn allot for ya.
Thank you for the video it Helps
well done. I will rebuild my batteries.
Thank you for the video, it's helped me take mine apart and somewhat understand what's going in there. However when checking my cells they seem to be okay. I have a 5 amp hour pack and so the way they're wired I can only measure two of them that are together. When I measure each set of two, they're all very consistent at about 7.6v. Before I took it apart it would charge up to 2 bars and then the charger would start flashing red. Any ideas? I guess if I un-solder the cells I can check them individually.
They are together in the 5Ah, but 2P or 2 in parallel so it will still be voltage of one cell for example 2.8 - 4V. You will know if one is bad because it will also affect the other one in parallel with it.
@@ThriftyToolShed thank you! So actually I think my cells are okay then. Any other ideas as to why I'm only seeing too bars before the red blinking starts?
@@BruceChastain
I have not seen this exact issue with these packs as I have only worked on a couple of them now. I imagine you have verified the fuse is good. I would check that all balance leads measure correctly all the way to the board and if all else fails you can see if it's a microcontroller on the board to do a reset on possibly. I have shown that on a couple of other brand packs over the years. Some Ryobi, Ridgid and 58V ECHO packs have a header plainly marked and I jumped rst to gnd if you happen to see that. That is all else I would know to check from here...
Great video thanks and I did order one of those little spot welders and polymer battery,
that beats the hick out of my soldering jobs
thanks for the info
Awesome. If you don't already have some XT-60 connectors or leads you may want to get some to make the connection to the board easier. If I remember correctly it comes with ring terminal leads so I made up some cheap XT-60 leads for it. Thanks for your kind comment!
what kind of cells did u put in there my moms battery is going out was going to try a repair
These were cells I had in a scooter battery not being used so basically new cells. Not any that I bought for this video. I mention in several videos and show using cells I get from 18650batterystore.com. I look at the Deals tab and usually see if they have a really good deal on some very similar cells and sometimes you can get them for half price.
This is an example of some similar cells I would use if purchasing some for this example of a pack. If you would rather have the name brand cells, they have some of those on sale also.
www.18650batterystore.com/products/eve-20p
I was looking for information on Kobalt 40V batteries and came across your channel, this has to be one of the best videos on TH-cam about lithium batteries, thank you very much for sharing such great material.
Have you ever come across a Kobalt battery pack that flashes red on the charger but all cells look ok and have about the same voltage? I have one fairly new 40V 4Ah pack where all cells are presently showing around 3.98V but the gauge on top only shows two leds, and now the charger only flashes red when I plug it in. Is there any other test I can try without fully dismantling the battery pack? Or could it be the BMS itself that failed?
Thanks for your kind comment. I have only worked on a couple of these packs and have not seen that myself. I would think it is a problem with the BMS. If the overall voltage is good at the terminals, I would say that most likely points to the BMS board. The last thing to try might be to see if a reset is on the board. The board might be potted and make that nearly impossible on some. Some BMS boards have a spot like programming header, and jumping reset to ground can sometimes reset the microcontroller and can work sometimes. It's a long shot, but I have a couple older videos that it did help. I shared this on an ECHO 58V pack repair and a Ridgid pack repair video. It is the only thing left to try that I can think of. Best of luck to ya!
@@ThriftyToolShed Yeah mine is indeed potted, I also have a good working battery which is also potted so at some point I caught myself looking at still frames in your videos trying to identify such test points in the BMS PCB 😅 But I don't want to disassemble the good one and risk finishing with neither working afterwards. Guess I'll end up purchasing another battery pack and I'll later upcycle these cells on other projects. Thank you again for the excellent content!
The orange cells you are using as replacement from hover craft battery are not suiteable for kobalt battery as they use high discharge li ion sanyo rx 18650 with 20A continues discharge rate while one you are using dont have high discharge concequently battery will die again once you put load on this kobalt lawn mover using this battery from orange chinese cells.
It's actually working perfectly still today as it's only for a string trimmer and I tested it fully. I am aware of the cells. It also kept a battery from being useless to working better than the 1P pack from the factory for 2 years now. Other than that you are correct. Thanks for your comment!
Good👍👍
Ur welkom, can you give me the link to buy both of these spot welders from ali express, i shall be thankfull to you..
I have the Amazon link. If you need an AliExpress I will see if they sell it...
amzn.to/3TwfYkk
These are 2 close to the ones I use on AliExpress.
www.aliexpress.us/item/3256807162493370.html?spm=a2g0n.productlist.0.0.1fdb6c06S5ZQV5&browser_id=c53d1709d1084d4d9a9316b354719e5c&aff_platform=msite&m_page_id=caakhnpiwcawxyuu190d8017b5ce0eeae5314f361e&gclid=&pdp_npi=4%40dis%21USD%2133.83%2116.91%21%21%21245.00%21122.50%21%40210324f117216112544314907eecaa%2112000040365948985%21sea%21US%210%21AB&algo_pvid=681289c5-13e0-470d-a2db-4b2f1c825959&search_p4p_id=202407211820545451004439392500003500696_3
And
www.aliexpress.us/item/3256807092772157.html?spm=a2g0n.productlist.0.0.1fdb6c06I0cjjw&browser_id=c53d1709d1084d4d9a9316b354719e5c&aff_platform=msite&m_page_id=caakhnpiwcawxyuu190d8017b5ce0eeae5314f361e&gclid=&pdp_npi=4%40dis%21USD%2132.86%2124.64%21%21%2132.86%2124.64%21%402103011617216112234858127ed04e%2112000040045495998%21sea%21US%210%21AB&algo_pvid=154a966b-ae94-495d-8738-251bf60e49a3&search_p4p_id=202407211820232773531632103450003333381_1
What does the ohm symbol connection do? I'm trying to run a kobalt mower off of a different 40v pack and it's not working. Does it need a resister to neg terminal. I tried to watch this video and take a closer look at the board but it's hard to tell. Thanks
It is marked as "COM" on the board and it is the white wire that goes from the connector board to the battery monitoring board. I briefly showed the white wire on the very basic drawing I shared of the wiring. I did not share much about it since I did not need to for this repair. I have not had the potting off the monitoring board to know for sure what the 2 center connections do. I would think the COM is more of communication between the pack and tool and possibly pack and charger, but not 100% sure. Some packs need a NTC or resistor to give a feedback for temperature to work, but I think this is much more. These Kobalt power tools and packs are made by Chervon that makes EGO, Flex and SKIL. I have spent time trying to figure out the D-Terminal on the EGO packs that are similar and uses communication between the microcontrollers so it gets complicated when you have no schematics or any information on these except what we figure out on our own. Hope it helps some. Best of luck to ya!
Thank you for the information. My mower has three wires only and I tried the resister to simulate a temp but wasn't sure exactly what it needed. It's the connector closest to the neg. The other connector I think is the comm one isn't used but I may not be looking at it right as I don't have a kobalt battery.