Yes, and also.... Please make a good faith attempt to understand allowable continuous discharge rates for the batteries. (Spoiler: Most battery packs are going to be well within a safe range and may also limit output current.)
For example: If a drill has a maximum current draw of 2 amps and the pack is only capable of discharge rate of 1 amp, you are risking a thermal runaway condition. (Lithium batteries get esplody in those conditions.)
Battery packs generally use a series-parallel wiring arrangement to decrease per-cell discharge and any protection circuits should limit total current draw. Knockoff battery packs may lack protection circuits, but for this specific problem the way the batteries are wired should prevent or limit any issues.
(I get a bit preachy when it comes to battery safety. Sorry. Many people simply do not realize how energy-dense our device batteries are these days.)
I made Franken - Bluetooth speakers. Works better than I thought. One 3rd party ryobi battery is enough for a festival week. The second Bosh lawnmower battery adaptor works fine too.
A couple years ago I got an electric lawnmower super cheap. I only discovered earlier this summer the lawnmower and accompanying weed whacker were being discontinued, and if they break in ways I canāt fix, Iāll have a 60v, 5 amp battery to recycle play with.
It hasnāt occurred to me to reuse the battery for some other fun project. There will be shenanigans.
Oh my, you're who I want to talk to. I have been thinking about making a speaker probably for the opposite reason you did. I want it to be quiet. Quiet as a little mouse. Do you mind guiding me towards your method? Because I am just at the beginnings, but I was wondering if the hardware does the work, or if you get the fixings and then load the hardware up with something open-source. So if you've got the time, please let me know!
On higher end ones maybe, but this works fine so idk - it's conceivable they both use the same internals just with a different battery mounting geometry
Mostly only the charger cares. A tool often only has power contacts. Something "smarter" like a camera with battery life gauges in the menu etc will most likely want to talk to the battery.
But if the company thinks the extra cost in manufacture is worth it, they'll probably choose evil.
I did this with a gi-fucking-normous Ridgid "X2" my dad got me when I was in college. It was originally niCAD, though it is actually compatible with their current batteries. However, I had cobbled together a collection of electrically compatible low-end stuff from Stanley-B&D that just needed a couple of kisses from a dremel to fit each other. Everything but that one drill is either B&D, Porter Cable, or Bostitch (not the nailguns that use dewalt batteries, rather some drill/drivers from when they were the brand SBD tried to pawn off on Walmart as better Black and Decker but won't cannibalize PC sales).
The old Ridgid is too heavy to have as my main drill, but it works fine. I keep a countersink bit in it and it's nice to have around. These B&D batteries have some basic overcharge and over-discharge circuits in them and shouldn't mind which device they're plugged into. The DeWalts are the ones that rely on more sophisticated circuitry in the tools to manage batteries, so they're the ones you generally want to avoid playing with.
I'm curious if the Craftsman V20 series they've been selling at Lowe's for the past few years is compatible with 20V Porter Cable stuff? I can confirm that the orange Black & Decker branded 20V stuff is the same overall design but has a different pinout and different overall dimensions so it isn't "grind off the little nub and it'll fit."
I also believe they're different than the DeWalt series, though my understanding is some Mac power tools (or Matco or Snap-Off, one of the debt truck brands) are rebadged DeWalts and their batteries are compatible.
The pinout on the orange B&D is exactly the same as PC 20v, and there's only like two little nubbins of plastic on the battery case, and two tabs on the PC tools that make them physically incompatible. I use them interchangeably after some dremel engineering (that gets nowhere near the electricals). Same as those now-retired Bostitch 18v, and I understand non-US "fat max" batteries and a certain limited line of 20v craftsman stuff from a decade ago is also the "same."
The newer Craftsman that S-B&D makes looks to have been designed along similar lines, but they flipped + and - and added enough plastic-work that I think it'd be non-trivial to hack them up. I haven't investigated to see whether, electrically speaking, they are more B&D or more DeWalt.
Be careful... IIRC, DeWalt batteries actually rely on circuitry in the tools, and it's possible for an old tool to over-discharge them and reduce their capacity pretty drastically. Specifically, it seems the "low voltage cutoff" lives in the tool for DeWalt (and Makita and Milwaukee I think), while Ridgid, Ryobi, and B&D have it in the battery. The two former are for backwards compatibility, and I think the latter because god knows what stupid garbage tools they'll throw at the line next (though my B&D sander is... fine).
@wjrii Thanks for the good information. I knew that PC NiCad tools had no communication to the battery, not sure about their newer LI ones. Regardless I find that the DW batt last so long on the PC tools that I always end up charging them when I think I should rather than when they actually need it. Rarely do they get down to 1 light, let alone full discharge As the PC tools die (which is taking a very long time, only 1 of 9 so far) going with DW brushless which have even better batt life.
FWIW, my Makita drill (18v) definitely has the BMS in the battery pack. I have two packs that came with my drill and I have re-celled both of them with fresh 18650's, so I was in there to take a look. I've had the drill itself apart, too -- there are no smarts whatsoever in there. I don't have any other tools in the line, though, just their basic drill.
What's astounding to me is that there is no provision whatsoever for balance charging or individual cell monitoring. The packs are a 5S configuration and treat the entire series lump of cells as a single whole. If one of your cells shorts the BMS will never know and your pack will just go off bang. Maybe it'll trigger the low voltage cutoff first if you're lucky...