Sanity check on Worx 20V battery pinout before I solder anything

[Thomas Martinez]

Just did some digging into the dead Worx 20v pack to see what the deal is with each pin. I think I've got it all figured out but I want to make sure no one else is about to fry there charger on me when they try to use this.
So the most obvious. Is negative and + is positive. Then BH is the battery enable pin, BS is the battery sense / identification pin. Vcc is the logic voltage from the charger. L is the thermistor for the tool to sense temperature, should be NTC thermistor. Finally C1-C4 is the junctions between each battery pack group, for balancing during charge.
I'm somewhat confused about the exact use of BH and BS, but Vcc appears to be required to enable the battery to turn on entirely.
If anyone have done a rebuild on a Worx 20v tool let me know what you've found on this topic. Also just wanted to check if the C1-C4 pins are in order from bottom to top of the battery pack like you'd think, or if Worx did something different.

 

[Fut]

BH on these isnt just a dumb pull to enable the battery. The tool and BMS has to perform a handshake. If the tool doesnt get the response from the BMS in a given time period the BMS will shut the FETs and no longer allow the battery to be used.

 

[Stormy Stag]

why do they even bother with a handshake on a 20v pack? feels like overkill for what is basic 5 cells in series

 

[Sparkling Snake]

c1-c4 are bottom to top in every worx pack I've cracked open, no funny business there. Just double check with a meter from B- before you trust it though, you definately dont want to swap two by accident

 

[Breakable Baboon]

dont solder anything until you confirm vcc with an oscilloscope. Multimeter wont pick up the pulse train the BMS sends back when BH is pulled.

 

[Fut]

why do they even bother with a handshake on a 20v pack? feels like overkill for what is basic 5 cells in series

It's so they can sell you their proprietary battery packs and brick any third party brand that tries to replicate their tools function.

 

[Save Yourself]

Genuine question for whoever knows the answer to this, since BH on the battery is supposed to recieve a response from the BMS, does that essentially mean you cant use the cells without the BMS in place? Or can you use a small MCU to provide that response?

 

[Bewildered Bat]

You're overthinking this. Just use the original BMS, replace the cells. Why are you trying to reinvent the wheel.