Help understanding JK BMS and on/off switch

[buckeyestargazer]

I'm adding a JK BMS to a 4S 230AH LiFePO4 battery and I'm wondering about the included on/off switch. This is the first BMS I have that came with a separate switch. The Daly I was using before was just "on" when connected to the battery. But it appears that the JK switch needs to be "on" in order for current to flow.

The switch is convenient I guess, but this battery will be in an RV in a location where it is not the easiest to access, so I'd rather not have to turn this switch on in order for the BMS and battery to work. What am I missing?

 

[MrThisIsME]

Never seen a JK with a switch either. Not to state the obvious, but would this not be a set it and forget it switch?
Can you still cycle flow through the app like the others? If so why worry?

 

[buckeyestargazer]

Never seen a JK with a switch either. Not to state the obvious, but would this not be a set it and forget it switch?
Can you still cycle flow through the app like the others? If so why worry?

Here's the one I bought: https://srikobatteries.com/product/...-8s-200a-2a-balance-current-with-uart-rs-485/

I don't know about a "set it and forget it" switch, but when the switch is off I cannot connect to it via bluetooth/app, and there is no voltage/current on the P- side. When the switch is on I can connect and there is power.

 

[Ep1phany]

I'm adding a JK BMS to a 4S 230AH LiFePO4 battery and I'm wondering about the included on/off switch. This is the first BMS I have that came with a separate switch. The Daly I was using before was just "on" when connected to the battery. But it appears that the JK switch needs to be "on" in order for current to flow.

The switch is convenient I guess, but this battery will be in an RV in a location where it is not the easiest to access, so I'd rather not have to turn this switch on in order for the BMS and battery to work. What am I missing?

That's the power switch that comes with most of the JK's and is nothing new. You don't need to keep turning it on and off. Install your BMS, turn it on and you can leave it on. I only turn my JK BMS off with that switch when I'm disconnecting it for maintenance.

 

[buckeyestargazer]

That's the power switch that comes with most of the JK's and is nothing new. You don't need to keep turning it on and off. Install your BMS, turn it on and you can leave it on. I only turn my JK BMS off with that switch when I'm disconnecting it for maintenance.

What I don't like is that the switch LED never turns off. It certainly doesn't draw much, but I don't like the idea of any draw on the battery while I'm not actually using it.

 

[kommando]

Mine has been on for 7 days, I may turn it off in a few months or maybe not.

 

[wsaharem]

It’s a push once for on and hold for 3 seconds for off (or at least it works that way for my inverter version). It’s handy when starting out and working through all the settings.

 

[Bleedingblue]

What I don't like is that the switch LED never turns off. It certainly doesn't draw much, but I don't like the idea of any draw on the battery while I'm not actually using it.

Unplug it then

 

[buckeyestargazer]

Unplug it then

Good point LOL. I mistakenly thought that unplugging the switch while "on" would turn the BMS "off" but it doesn't.

 

[740GLE]

Top tip you don’t even need the switch to turn on the BMS, just use a DMM in diode test, connect to B+ P- terminals of the BMS and you’ll hear a beep and see the LED on the BMS turn on.

Btw that BMS led is always on too.