Heatsinking the Vedders Anti-spark switch

Hi guys!
I am currently building Vedders anti-spark switch and came to an question:
As far as i'm concerned the only reason to do two-sided board is this connection:



Which is obviosly doable with jumper cable or even with trace on one-sided PCB, the kind of PCB that i can make easily (i can make even two-sided with a bit more hassle, but i can't metallize the holes)

But then I thought - maybe second reason is critical heatsinking of the MOSFET's through the PCB copper?
So the question is - Is there really a necessity for a two-sided board because heat dissipation of 5 square centimeters of copper, or can i get away with single-sided board?

your better off just making one of these to suit your needs its a lot cheaper. https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142#p586436.
i printed out a box and to put it in with no heat sink and never had a problem.

xadmx said:

your better off just making one of these to suit your needs its a lot cheaper. https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142#p586436.
i printed out a box and to put it in with no heat sink and never had a problem.

Click to expand...

Thankyou for your answer.
That switch looks cool!
Unfortunately i have already ordered IRFS7530TRL7PP MOSFET's, most expensive part, but while i am waiting parts, i will make your switch, as the parts are far more cheaper and readily accessible.
And this scheme looks more parts-efficient than Vedder's anti spark switch. Always thought that using TWO 240 amps mosfet for 50 amp continious VESC (or two of them) is a bit of an overkill

xadmx said:

your better off just making one of these to suit your needs its a lot cheaper. https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142#p586436.
i printed out a box and to put it in with no heat sink and never had a problem.

Click to expand...

Hey xadmx - Could you share more specifics of what this is? Maybe a pic inside the box? The link goes into a discussion w/ several options and just unclear which you are using.

Looks like a great option though!

xadmx said:

your better off just making one of these to suit your needs its a lot cheaper. https://endless-sphere.com/forums/viewtopic.php?f=3&t=40142#p586436.
i printed out a box and to put it in with no heat sink and never had a problem.

Click to expand...

That circuit has a track record of blowing FETs. If your controller caps are small and the voltage isn't too high, it might survive. I think it would actually do better without the capacitor. Seeing how the riba spot welder handles turn on surges of thousands of amps, a fast turn-on can work. I'd also add a 12v-15v zener across the gate to source as a transient protection.

As far as heat dissipation goes, do the math. If you know your maximum and average current and the Rds of the FETs, we can calculate how many watts you need to dissipate. This will tell us if you need a heat sink. A single TO-220 package in free air can dissipate about 1.5W. Potting the whole circuit in silicone or epoxy will help dissipation as well as making it waterproof.