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I found a cordless vacuum cleaner in my neighbors trash. It didn't work, which is probably why it was thrown away. However the batter pack seems to be perfectly fine. I opened it up and tested each battery on the multi-meter and they all measure exactly 4.1v, which I assume means they are good. The pack outputs 24v. I don't know much about these lithium battery packs so I have a few questions.

1) Is this a "battery management system"? Do I just feed it 24v to charge the cells and the circuit board manages everything for me? Or do I still have to monitor it for overcharging?

2) I wanted to power a cordless drill which I also found in the trash but that doesn't have its own battery. The cordless drill is rated for 18v. Would using 24v be okay? Will the battery pack tolerate being used for a drill instead of a vacuum cleaner?

3) How can I expand the capacity of the battery pack? Can I just solder on more 18650s?

4) I also have an old UPS with a dead lead acid battery. Can I use the 24v lithium pack as a replacement for a 12v lead acid battery?
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>>2207447
Oh also, question

5) On the output I can see P+ and P- which gives 24v. But what does "SC" and "DA" do?
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>>2207447
If cleaning your keyboard is too much of a task for you, the answer to all of your questions is no. And if you were capable anyway you'd know the answers already. Also search engines are your friend, these are the kind of stupid question that don't deserve their own thread.
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>>2207447
1) Yes, that’s the BMS board. The charger probably feeds it more than 24V though, you would need to look at the OE charger to see. Putting in 24V would likely give you like 70%-80% charge because 4.2V/ cell or 25.2V total is 100%.

2) Maybe, sometimes there’s electronics too that need to communicate, like a temp sensor, and the + and - aren’t the only two connections

3) sure, make sure all the new cells are matching though, and make sure you solder them well so it doesn’t burn up

4) probably not

5) one is probably a temp sensor to shut down charging or use if it gets too hot, the other, who knows
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>>2207447
clean your keyboard
>1
yes it's a BMS, that's why it's connected to the batteries and has "BMS" written on it
>2
depending on the model, it could be okay, it could run for a while and then fail, or it could immediately fizzle. older models without complex electronics will likely do better, but no guarantees
>3
you cannot (well if you could buy a full new set of well-matched 18650s you could double it by putting extras in parallel with each battery). you'd have to discard the old cells.
>4
no, unless you have a 12v regulator that isn't resistive and can handle high power (you don't)

>>2207448
>5
probably an I2C bus, SC is a clock and DA is data
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>>2207447
>that keyboard
>picks things out of the trash
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>>2207447
1.Yes
2.No
3.Don't waste your time.
4.No
>>2207448
5.The battery was both charged and discharged in a dock. The fins that were removed from those points were on that end. It's like that because there is a built in amp controller for output, because a portable vacuum cleaner is not a computer.
>>
>>2207447
Alright what is your keyboard. I can't see a windows key, so I imagine it's old, but the way you don't look after it suggests it's just trash.
>>
>>2207513
looks like an ISO layout IBM Model M keyboard. pretty good one with nice switches. the ANSI ones are decently sought after, not sure about this layout.
>>
Based thrashcollector Anon.
>>
>>2207513
>>2207524
I found it in the trash, it's some old keyboard with a round pin collector. I bought an adapter off ebay to use it via USB
>>
>>2207524
it's not a model M. it's just an old rubber dome keyboard
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>>2207465
He found the keyboard in the neighbors trash too.
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>>2207447
A. throw that disgusting keyboard out.
1. yes
2. feed the board at least 25.4vdc. an 18 volt drill uses 21 volts max. it might be able to handle 25.2v but I would use a buck converter to get it down to 12 for a 12v tool. you don't have money so I guess you won't be doing that.

4. short answer no. long answer nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo!
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>>2207447
I think getting the cells out of there and using them with a new bms is gonna be a better idea.

You can get a small usb bms with basic protection for like 2 dollars.

https://m.aliexpress.com/item/33061983626.html?spm=a2g0n.productlist.0.0.517e74adyKmHel&browser_id=5e699abd0bda4ba7a76f2cfa5da839e0&aff_trace_key=cec019ba7fe14bd09fabc252a59fa5ec-1631724143128-09509-UneMJZVf&aff_platform=msite&m_page_id=17bea5752b51d3d849581ebf658e324f0630d319b4&gclid=&_imgsrc_=ae01.alicdn.com%2Fkf%2FHf639b291abe54e98a0c95e4932925615G.jpg_640x640Q90.jpg_.webp
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>>2207597
Kek'd.



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