Dewalt A123 Hospice Hookup Query

[HYBike01]

For over a decade I have used the complete set of Dewalt 36v tools and a year ago I picked up 100 A123 cells, with 85% remaining for $100 USD. I grab spare Dewalt 36v stuff whenever it pops up for a bargain, including old battery packs (the A123 not the Samsung) and wish to power other items with the packs. To utilize the same packs to power a 12v transmitter and a 12v receiver, first the 36v must be stepped down to 12v. (DC converter pictured).
To connect the packs, to a non-dewalt device without modifying the packs, requires an interface. I am not 3-d printer savvy and opted to cannibalize a broken dewalt 36v drill and dewalt 36v light. Opening the drill I encountered more wires than expected and prompted this first post (Although I have been a lurking member for a while) The drill is pictured below:

My first thought is the purple and brown clips are pos and neg and the rest isn't needed. But, I have read about over discharging and BMS problems and decided to ask the Endless sphere brain trust.
I am fond of the Dewalt 36v, they are heavy and bulky, but have done well by me. And with my latest A123 battery score, I feel like I am making money using them. If, when the packs stop lasting on the tools, I can use them for low volt (12v or less) applications, that would be aces.

 

[amberwolf]

Where do the wires actually go in the drill? If you draw up a diagram of that it will help you (or help us help you) find the point where the battery voltage is directly available (which is what you want).

It might be easier to trace out the light, since the drill is probably variable speed and may have electronics in it to control the current to the motor, while the light is probably just on/off and would likely have only the main power wires in it.


BTW, the dewalt packs were used in several "tool pack" ebike builds here over the years, so it is likely that at least one of those has a wiring diagram or equivalent that may help. I haven't gone back and read any of them yet, but this is a list of at least some of them (not all of them will be relevant, though)

ES 1.0 Graveyard - Search

 

[HYBike01]

Thank you for the reply, I had read much of the information collected on the Dewalt batteries, over the years, but it was nice to have it arranged nicely in a link. My post was a final check before engaging. Most of the information surrounds increasing battery power, I seek to step down batteries. I decided the internal circuit boards are, more likely than not, for battery protection and should be retained. The advice provided was sound, the light proved easier to understand and lead to the discovery that not all the necessary pieces had been harvested from the drill. The internals of the light are pictured below:

Not sure why it posts sideways? I attached spade connectors to what looked like spade connectors on the end of the brown wires (the original connectors were non-standard). It took more time than it should have, because custom solutions have custom problems.

Voltage at the exposed spades read 35.5v (It is a 36v battery, purchased over a decade past) I know that is not the best indication of remaining battery life, but it brought a smile. I am going to use one battery to power a wireless receiver and a fan; one battery to power a wireless transmitter and a fan. 36v will be stepped down to 12V, 5amp. Fans are 12v computer fans, I am considering running two per battery, as voltage converters, transmitters and receivers all run hot. My concern is battery life with an additional fan load.
I realize this is not directly electric bicycle related, but I have kicked around a hybrid bike for as long as I have owned the batteries and I have learned much about these batteries and batteries in general at endless sphere.
As for my paper hybrid bike (which for health must now be a hybrid trike) A four-stoke, .49cc (modified) engine powering a generator to charge one bank of batteries while another is in use. Since the engine wouldn't be connected to the drive train and sizing the electric middrive to 750, pedal assist, I believe it would meet the letter of the law for an electric bicycle. Food for thought