Congratulations! Repurposing lithium tool batteries have been on my plate for the last few months. The circuitry is a BMS. Pretty much every manufacturer has gone to a dumb tool, smart battery type setup. The BMS serves several functions: 1. Low voltage cutoff: When the battery is discharged, the BMS disconnects the - terminal on top via a MOSFET that's typically bolted onto the side of the pack on a heatsink. 2. Cell monitoring/balancing. The BMS monitors each cell and will perform a cutoff if one is out of balance. It will also perform cell balancing while charging. 3. Temperature monitoring. One of the other terminals is a temp sensor that informs the charger when the battery is hot. Charging is limited or suspended when the battery is overheated either from use, or from charging. The bottom line is that the BMS is a ultraconservative safety system. Pretty much if anything is the slightest bit out of whack, the BMS's typical response is to turtle the battery, rendering it unusable. Also it's for the most part proprietary tech. You're not going to find schematics, or charging profiles, voltage/temp/current limit specifications, or pretty much anything else about the BMS and/or the stock charger for any of these systems. If that BMS remains in the system, then your best bet is to treat it all as a black box, get a stock charger, and use it unmolested. For the adventuresome though, the solution is pretty easy: crack open the battery and bypass the BMS. It can be as simple as adding a wire to the negative terminal of the battery. This video describes the process for the Ryobi 40V system: https://www.youtube.com/watch?v=3DQAFPnXDZqZ8 But after looking at a few different types, they are pretty much all the same: the BMS is connected to each cell of the battery via a wire or a tab. Solder your own wire(s) at the attachment points, then use your own wires for charging/discharging. As pointed out in the video, often those attachment points are labeled CL<+/-> representing Cell, The number of the cell in the string, and the positive/negative terminal of that cell. So the CL10+ on the ryobi for example is the positive lead of the battery because it's the posive terminal of the 10th cell in a 10 cell pack. CL1- is the battery negative. My interest is recorganizing smaller packs into larger for useful ones. In particular I'm interested in the Kobalt 24VMax series sold by Lowes. Their 1.5Ah battery is sold new for $10 each. As described above, there is a BMS attached by tabs/wires. So the cells can be paralleled using the intercell wires, and put in series also. My goal is to replace the lead acid 48V Ryobi self propelled lawnmower pack with a 48V 7.5AH battery made up of 10 of these $10 packs in a parallel/series configuration. Hope this helps, BAJ On Thu, May 17, 2018 at 04:21:07AM -0600, 99guspuppet wrote: > I am now the proud owner of 3 battery packs from Goodwill Industries. > Model 29068 20V 6AH Lithium Ion battery pack > Inside each I find 10 battery cells and lots of circuitry. > Outside is a status push button that says the ???goodness??? of the packs= is: > #1 4 green LEDs of 4 > #2 3 green LEDs of 4 > #3 3 green LEDs of 4 >=20 > The packs have 4 terminals: > - > C > ohm symbol > + >=20 > I have been trying to find a schematic or a method of charging these pack= s. > Also a correct method of using their power. waahhhhh ha ha ha >=20 > Best > Gus in Denver ???. moved to Arvada > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 Byron A. Jeff Associate Professor: Department of Computer Science and Information Technol= ogy College of Information and Mathematical Sciences Clayton State University http://faculty.clayton.edu/bjeff --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .