EBoard Mosfet Switch

Yep! Will do.

Dual IRFB7530 version with 12V LED push button integration.

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!!!VERY IMPORTANT NOTICE!!!

The gate resistors for the MOSFET('s) can not always be just 10K resistors! I was originally doing this and its wrong! The 2 resistors act as a voltage divider for the gate but you have to make sure the voltage is not over the Vgs max of the MOSFET. For a 12S build you will need a 24-32K Ohm resistor on the positive side and a 10K on the negative side of the voltage divider. For a 10S build 18-25K Ohm on positive side and 10K on negative. For an 8S build 2x 10K’s would be fine but a 12K on the positive side would be better. 6S Build two 10K’s are fine as well. You can also use a mismatch of different resistor values using a Voltage Divider Calculator to calculate the required values, just don’t use any resistors under ~1K Ohms. I put an example below so you can get a better understanding.

USING A 12V ZENER DIODE TO DRIVE THE GATE WOULD BE BEST! Using a 12V Zener would mean the gate always gets 12V no matter what the voltage is, as long as it’s above 12V obviously.

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Dude I am totally interested in one of these. I have a 13s 3p lithium battary pack that I made myself for a single drive motor. What is my cheapest option for one of your switches?

@Chicagojoshua - 13s is going to be tough to find an ESC that will work. Most max at 12s. Not sure if the mosfet switch will also be limited to 12s max?

Hey @sl33py my switch uses the IRFB753PPbF MOSFET which has a max voltage of 60V so you could technically use a 14S battery. Also most components that have a max of 12S can probably handle 13S-14S just because not many parts have a max voltage of above 50.4V(12S full charge) and below 60V so usually there max is 60V, not much in between.

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Ok,

So which switch do you recommend and how much will it cost me for the LED push button version you make?

Well its up to you on which one you want. Either one will work for your single drive setup though the dual MOSFET one that’s $35 instead of $25 will future proof you more because you’ll be able to use it with a dual drive setup if you ever decide to go that route. If you want the LED Pushbutton its an additional $10 so for the single FET switch it will be $35 and the dual would be $45 though like I said my prices are negotiable.

I will purchase two… one a single drive and another for a future dual drive both with the push button LED. Whats the best price you can quote me?

How much for just a blank pcb posted to uk ? Single 6s setup

A blank PCB for one of the switches? No components just the PCB right? I guess I could send one to you, ive never shipped internationally before so I dont know how much it would be though. I custom make all my PCB’s using a laser printer but you could try using the Toner Transfer method to make one yourself and it would be quite a bit cheaper.

I was wondering if someone could double check me on my switch drawing. Should be essentially the same as @JdogAwesome made.

Looks good though you’d be a lot better off using a 12V Zener Diode’s to drive that MOSFET gate as it’s more stable at different voltages, other than that looks great!

Cool, appreciate the tip! Also I believe you may have told me a while back But I’m still confused on the purpose of the diode (1N5404) I believe you (or maybe it was someone else) said it had to do with the regenerative breaking? But how does it help / what exactly does it do?

@dstnceswmer he is using it as a flyback diode

So here is an updated pic with a zener diode being used, and two schottkey diodes added in line with the charger to prevent any possibility of a reverse polarity charger damaging anything. Also made the picture more accurate in that there is a barrel plug for the charger. Everything looking good?

A single 7530 MOSFET is not going to be enough for 60A continuous

In addition, most anti-spark switches have a capacitor and resistor in series, connecting the gate to the drain. It’s my understanding that this is what limits the inrush of current to the ESC’s caps, preventing the spark

? The data sheet I have says that it is rated at 195A Continuous drain current at a 10V Vgs. So why wouldn’t one be enough?

You want to keep the power dissipation to around 1 W per FET. With a single 7530, you would be dissipating 4-5 W at 60A. A single 7530 should really only be used up to 30A continuous, and even that is pushing it a bit. Otherwise you need to incorporate passive or active cooling

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@jmasta @dstnceswmer A single FET is fine for your use. Your board only draws around 20A nominal with peaks UpTo around 80A but that’s for a very short amount of time and it can handle it fine. @jmasta about the capacitor resistor on the gate to limit inrush current thing, no you should not do that. I was talking to some very smart electricians on Stack Exchange and they were saying it isn’t healthy for FET’s. Also inrush current doesn’t matter because it’s a MOSFET so there is no sparking and they can handle extremely brief high inrush current no problem. Also I’ve been using a single 7530 FET as a switch for my board for a while and it works, so yeah.