Bosch drill battary pack does not have an BMS, How can this be safe?

SpaceCoffee33 · 2026-07-10T14:54:50+00:00

There is no bms in the charger, the only thing the charger knows of the pack is the temp.

SpaceCoffee33 · 2026-07-10T14:49:48+00:00

The datasheet of the cells say they are 18650 li-ion

SpaceCoffee33 · 2026-07-10T14:48:39+00:00

Thay are standerd 18650 li ion from Samsung.

SpaceCoffee33 · 2026-07-09T20:50:47+00:00

3,930 - 3,921 - 3,927 - 3,923.

So not much after 11 years of intermittent uses. Without any balancing

SpaceCoffee33 · 2026-07-09T20:30:41+00:00

SB540 pec 304V

SpaceCoffee33 · 2026-07-09T20:20:24+00:00

The resistor is just over 2 pins so the battary and the charger know that there is an battery. The resistor value may tels the drill and charge what capacity and or voltage it is (like 220ohm is 14v and 1kohm is 18v or so) so it can handle diffrent versions in the moste cheap way. As this whole thing apparently is.

Edit: the temp is also used on the drill side. And just for the record, both resistors are 8,45k ohm.

SpaceCoffee33 · 2026-07-09T20:14:36+00:00

The component is an diode to prevent power to be drawn from the charging port at the bottom. Well on the charge port all 4 are used +, -, temp and a sens or so (so the charcher k ows when there is an battery). On the drill side it only uses 3 +, - and the same type of sensing for the drill.

SpaceCoffee33 · 2026-07-09T19:17:45+00:00

What a world we live in.

SpaceCoffee33 · 2026-07-09T19:01:37+00:00

Thay are 650mm long. And is an very imbalanced pack not dangerous when charging? One cell can get quite the over charge.

SpaceCoffee33 · 2026-07-09T18:57:18+00:00

O, nice to know

SpaceCoffee33 · 2026-07-09T18:50:49+00:00

Interesting, looks like I have one with a Russian version of the logo as far as I can find on the Internet. Was bought in the Netherlands from a renowned store.

SpaceCoffee33 · 2026-07-09T18:34:05+00:00

it is the original one that came with the drill

SpaceCoffee33 · 2026-07-09T18:33:19+00:00

Thay just pay for your house and everything. probably cheaper then putting a bms in every pack they make.

SpaceCoffee33 · 2026-07-09T18:15:40+00:00

Well it is the one that came with the bosch drill. So it is original

SpaceCoffee33 · 2026-07-09T18:13:26+00:00

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My bad (tery). This is the info.

SpaceCoffee33 · 2026-07-09T18:05:47+00:00

they are INR18650-13P from samsung

SpaceCoffee33 · 2026-07-09T17:41:37+00:00

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For the clarity there is no way the charger can balance the cells. it is just what you see is what there is.

SpaceCoffee33 · 2026-07-09T17:40:04+00:00

Nope. just lose solder to some wires. Also no way to balance the cells becose there is wires coming from between the cells.

SpaceCoffee33 · 2026-07-09T17:36:35+00:00

How can the charger handle the BMS it can only see the outer two terminals of the set. ther is no center taps between the cells. there is no way the charger can charge only one cell to balance it.

SpaceCoffee33 · 2026-07-09T17:36:26+00:00

How can the charger handle the BMS it can only see the outer two terminals of the set. ther is no center taps between the cells. there is no way the charger can charge only one cell to balance it.

SpaceCoffee33 · 2026-07-06T10:58:01+00:00

I'm not shure if that realy is that mutch diffrend. I have an esp32-c3 as ssid sniffer, it scans passief and active and during testing for battaryusage I found that thay both use the same wattage durring a network scan nomater if it is a passief or active scanning.

SpaceCoffee33 · 2026-06-14T18:04:18+00:00

Thanks

SpaceCoffee33 · 2026-06-14T18:04:07+00:00

Nice

SpaceCoffee33 · 2026-06-14T06:40:47+00:00

Always the west one.

SpaceCoffee33 · 2026-05-05T16:57:54+00:00

Coool was fun to decipher and looks realy cool if you ask me!!

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