HCX-d131 without on and off switch

[eAdrian]

Hi

I have been reading few posts about people trying to install on/off switch on the DCX-d131.
But I did not manage to find information what happens if this BMS is run without switch.

Do I really need to have a switch? What happens if this BMS is on 24/7 ?
What happens if BMS switches off due to temp/over discharge. How is the BMS turned on again?

The BMS is having 20μA power consumption, that would mean it will drain battery over time?

The controller have on/off switch. Will that allow me safely connect the battery to the controller without getting the sparks? (using XT60/XT90 connectors without spark protection).

 

[Peter.bp]

Hi

I have been reading few posts about people trying to install on/off switch on the DCX-d131.
But I did not manage to find information what happens if this BMS is run without switch.

Do I really need to have a switch? What happens if this BMS is on 24/7 ?
What happens if BMS switches off due to temp/over discharge. How is the BMS turned on again?
The BMS is having 20μA power consumption, that would mean it will drain battery over time?

The battery is drained around 200mAh per year, so, don't worry...
The BMS has separate connection for charger, which allows charging the battery when P- is disconnected from B- due overdischarge.

The controller have on/off switch. Will that allow me safely connect the battery to the controller without getting the sparks? (using XT60/XT90 connectors without spark protection).

Probably not, suppose that the on/off switch only disconnects control circuit from power supply, not output stage.
You'd install spark protection module (if you want often to disconnect controller from battery) or at least charge capacitors of the controller output stage just before connection through serial resistor.

It seems that people are installing on/off switch using protection circuitry on the BMS in order to cut the power output to controller when not used. It is much cheaper solution as you need only small switch and serial resistor (around one MOhm) to activate protection (or use just the switch for shortening the thermistor used for temperature protection...
Such switch protects the connectors from sparks when connecting or disconnecting battery from controller (as the BMS protection is then used).

 

[eAdrian]

I might keep the battery in place until I change to spark safe connectors.

How to charge the controllers capacitors?

 

[Peter.bp]

Easiest way is to get spare connector pair for this and two resistors 47Ohm/1W.
Connect connect pair one to other using resistors.
Plug this between battery and controller (while the power switch on the controller is set to off) for couple seconds.
Disconnect resistors and connect battery to controller.

On my bike I installed the key switch between plus pole of battery and controller.
I put in parallel with that switch one push button in series with 100Ohms/2W resistor.
Before closing key switch I push the button for couple seconds and then close the switch.