@wuwica , @dstnceswmer, thanks for the input but It is not that easy, I’ve already looked into this, and dont know how to do it, that’s why i asked in the first place.
@wuwica this kind of dc jack is mostly used for radio that use both plug in dc power and battery but not at the same time. reason this dc jack can not be used for my purpose : when plug in, tip2 would bend out a bit just enough for tip3 lost contact at that black arrow(ur pic above). but we need contact to get the voltage, so this is not gonna work. Unless we use something similar to e-switch, i think.
btw, my knowledge of electronics is very short too. Maybe i missed something.
Yea that picture is labeled right, and I meant to use the transistor gate to take in a connection from the tip shunt.
When a dc jack is plugged into the connector the tip shunt will disconnect and will allow the drain/source to be connected. I was only assuming this would work so I just brought up the possibility. I’d use the transistor as a switch.
@kyo@wuwica@dstnceswmer I feel like your guys are making it to complicated lol. I think what would be easier is just having a push button connected to you battery so you can check your battery whenever you need.
Agreed. I just plan on having my indicator turn on with the board as per my original drawings. not sure why you would care if it’s on when the charger is plugged in?
Exactly, just makes sure the gate drains when you power down the circuit. And the reason its such a high value is so it doesn’t affect the gate voltage as a voltage divider.
@dstnceswmer Also, an update on my order for the 10x IRFB7530 MOSFET’s from Arrow they just arrived today and at first glance they look very nice, but the packaging was a bit overkill lol.
@JdogAwesome If your switch is 12V rated how is it ok to be using in your configurations? the way I see it (even at 10s) the potential across the switch is (Vbatt-12V) = (42-12)=30V > 12V
The switch is rated at 12V because the LED has the proper current limiting resistor for 12V that’s the point of the two 4.7K resistors is to add to that current limiting resistor. Just because a switch says it can handle 12V doesn’t mean it can’t handle higher voltages, to an extent.
So I’ve been running a few simulations in LTspice and from what I can tell, the led in my rocker switch is going to be screwing with my gate voltage on my FETs. Best I can guess is that inside the switch is an led in series with a 500ohm resistor (that would make it 12V tolerant) the cathode end of this is tied to the switch ground while the anode is connected to the center tap. Problem is that this small 500 ohms negates the affects of my zener and acts as a voltage divider with my current limiting 10k, effectively giving me a smaller than desired gate voltage. Below is the schematic I have been simulating. Any thoughts?
Your definetly right that the LED would affect the gate voltage. Though you shouldn’t be running anything off the gate anyway. The way I have it setup is so the LED terminals have there own channel with the two 4.7K resistors. Though with your rocker switch your saying there connected to the terminals right? The switch I use has separate terminals for the LED light, and terminals for the contacts.
Though with your rocker switch your saying there connected to the terminals right?
Yup that’s exactly what I was saying. It’s just an automotive rocker w/led. I can see how having the led on a separate terminal would work. looks like my options are:
See if I can crack open the switch and re-route the led anode
Buy a new switch with broken out separate terminals
Use some sort of 12V step-down regulator as gate/LED power supply instead of zener diode (prob. over complicating things)
so actually quite easily popped off the top of the switch and was able to seperate the led annode from the switch center tap. just as I suspected, was just a 500ohm res/led in series. So that’s a viable option.
I do however like the look of the switch you linked (thanks)
Hey, this is a nice thread!
I dont know if I missed it while reading this but is using one mosfet like in this diagram enough to power off/on a 6s 22.2V circuit on my board? Also if it is do you mind sharing a link where I can download the printout to try and make my own PCB?
Thank you!
