It’s time for more tool battery teardowns! This week, I’ve got a Craftsman 19.2V DieHard battery, and a cute little Ridgid 12V battery. They’re both lithium, and I’m going to dig into both of them, because that’s what I do with old batteries I pick up out of junk bins.
I read all your posts, but battery tear-downs are my jam keep em coming!
2018-09-04 by Russell Graves
Very nice! I tend to do battery teardowns as I have packs show up or I find them. They’re fun, but a bit less technically demanding than the stuff I enjoy doing. However, I don’t always have time for the more technical stuff…
2018-09-10 by Unknown
I wouldn’t call that PCB a battery management system, it’s likely just a safety circuit. There are two MOSFETs ganged together because each has a body diode that will conduct in one direction when off. When you put two together you can stop the current in and out. They are big to get the heat out with cheap FETs. An example of a minimal safety IC is https://www.ablic.com/en/doc/datasheet/battery_protection/S8254A_E.pdf.
2018-09-11 by Unknown
both battery was build by same company.
2018-09-17 by Richard
I’m still fully invested in the C3 set. I have 3 of these 19.2v lithium packs, as my 2 NiCD packs wore out. They’re still going fairly strong since I bought most of them between 2012-2013.
2018-11-10 by Unknown
I bought a general (not genuine) 6A/h pack for a M12 Milwaukee tool, and it didn’t contain any circuit. Just a bare pcb with thermistor. It’s normal, because Milwaukee has balancing inside the wall charger. And as for protection… let’s hope it won’t fry ) No fuses inside. And cells were only half of rated capacity, but ok, I bought it cheap.
2018-11-10 by Unknown
Oh, forgot to mention what I wanted to say on subject: over-engineering! )
I’m sure this scheme leaks some current, and you can’t turn it off.
2019-02-26 by avh
Thanks for this teardown of a C3 battery that educates us about the role of a battery management system!
I probably like many C3 tool owners are planning for the future. The C3 tools were made by Ryobi to Sears specifications but are mostly the same as Ryobi. They are fine tools I want to keep. Unfortunately Sears specified a different battery stalk so Ryobi batteries aren’t interchangeable. Craftsman was purchased by Stanley and C3 batteries are not on the new Craftsman site. Sears while it remains open is still selling the batteries. And there are third parties which I hesitate to go with.
Purchase adapter made by LaiPuDuo: google DM18GL (Milwaukee batteries), BPS18GL (Dewalt batteries). These are also on eBay. I don’t know if they have a BMS that’s capable of disconnecting the battery from the tool however. Someone would need to do a teardown.
Hi…first i want to say thank you for your post on the craftsman 19.2v and ridgid 12v teardown. I am lucky to have come across it. And i think its cool you like to dig around in stuff. I have 2 19.2v 4.0Ah 76.8Wh ML:130211004 craftsman batteries that look similar to the one on that post. I used them in some cold weather and they stopped working, though they show a charge. Digging around myself, i came across the thermistor and disconnected it from board (other side of board has a small black cylinder looking thing you see often on chips, it has 2 leads that connect to the board and the other side of board was the thermistor wires, it also has writting on it vz(m) 105°c b0915 PET…thermistor had no writting). The battery charge indicator now lights up after removing the thermistor and i assume the battery will work also. I want to replace them (to be safe), but dont know where to look or what kind to buy. Your post takled about a 10k ohm ntc ?? Are those whats used in the packs ?? I would have replied on the forum but didnt know how. Im not very tech savy…lol…any help is appreciated, and thank you…im not actually sure where this poseted but i hope you see it and you can get back to me here or at firstname.lastname@example.org
A 10kΩ NTC thermistor is easy to find - search eBay, you can get them for a couple cents each (or a bit more, if you only want a few). They’re generic and easy to find. It doesn’t matter what you get - while there are some different curves around, they’re generally close enough that it doesn’t really matter much. They just prevent the pack from charging when too cold, and, perhaps, do something if the pack is getting too hot (though depending on the cause of it heating up, there may not be anything you can do).
Though I’m not sure why the thermistor would fail. They’re pretty reliable.
Thank you very much. Im so glad you saw this and was able to get back to me. And yeah, it must have been the thermistor im assuming because it works with it removed. I was using a 1/2 impact on my car in the cold, fresh batteries werent working, then the indicator charge wasnt working either. Some research showed it could be the therm so i removed and bam, the indicator lights started working again…mist have been from the cold…So all i need is a 10kohm ntc…any other specifications, like temp raiting or something else??..you just saved me like $60…thank you
I don’t think you understand just how standard these things are. If you’re replacing it, just about any of the ones for sale will work fine. Please don’t use your batteries in that full temperature range, but it should work fine.
Lol…i had no idea they even existed until i took those batteries apart (some things i know almost nothing about…esp computer stuff like chips etc etc…lol)…im a little over concerned because i read these thing explode if to hot, and it may be that wire that prevents that…thays why all the questions…im a fix it yourself type of guy (cars, swimming pool pump, garbage disposal, 7series transmission etc etc, anything to get out of buying new) but if not for guys like you who are knowledgeable and experienced, with videos and such, i dont know how much success id have had. So truly, thank you. I hope theres some satisfaction in knowing your helping people.i appreciate you .