What is this connector for "FETSW"

[sshibly]

I took apart a JBD non-smart BMS too take a peek at the guts.

Any clue what the FETSW connector is for?

 

[Pappion]

Could be for disable switches for Charge FETs and for Discharge FETs.
Could also be a test port allowing FETs to be tested independently of controller.

 

[sshibly]

Could be for disable switches for Charge FETs and for Discharge FETs.
Could also be a test port allowing FETs to be tested independently of controller.

it is a common port BMS
so does still have charge FETs? the entire BMS below:

 

[Pappion]

My Overkill solar BMS phone app has a On/Off switch for charge and another for discharge.

2.4.6 External Switch
An optional external switch can be wired to the BMS via the included 2-pin pigtail (JST-XH, red/black wires).
If the configuration option is enabled within the BMS, discharging will be disabled when the switch contact is
open. When the switch is closed (or a jumper is in the place of the 2-pin connector), the BMS will operate
normally.
● External switch: Set this to True if you have an external switch wired to the 2-pin connector, as
detailed in section 2.2.6.

 

[Pappion]

it is a common port BMS
so does still have charge FETs? the entire BMS below:

I'm not sure why I remember or think there are two banks of FETs. No big deal, I could figure out with an ohm meter, diode check.
Just too cheap and easy to replace a bad BMS.

One the other hand, FETs like that have an inherent diode (Source to Drain), which could conduct in one direction when off.
So two (banks) FETs are connected in series with the diodes back to back so that off is really off.
I have done this in the lab on mobile phone charging circuits, replacing the shottkey blocking diode.
Either it was prior art in 2000 or big M owes me a patent award and the engineering staff stole it.