Recommendation for a high-current DC relay

Other Hardware General Electronics
1

Hi all,

I have an old Arduino Uno (about 7 years -- used it to control laser shutters) which I would like to use for a basic on/off temperature controller to maintain a 300x300x3mm Aluminum plate temperature at 37C (ambient is -25...+25C). The power supply is 12V DC (which I can double to 24VDC if needed), peak power output is ~200W (just below 20A), and sustained current is 10A. I initially considered using a "20A" 12V thermostat from Amazon (plenty of them are available), but reviews say that their "20A" rating is not real, i.e. they burn down.

Could anyone recommend an Arduino-switchable on-off relay with a proper 20A rating? I can also consider building a PID controller, but I want to start from something basic. There are heavy-duty 12-24DC PID controllers on digikey, but they seem to be rated only at 5 Amp.

I can get a newer Arduino if needed (please let me know).

Many thanks in advance!

2

I would look for a car relay. Those are made by millions and therefore cheap.

1 Like
3

I would look for a MOSFET that can handle your 20 Amps.

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I assumed that car relays were controlled by 12V

5

True, a transistor circuit is needed to control most all relay's.
The relay modules that are readymade for arduino use have that already. but I haven't seen any that can handle that much current.

While adding a transistor circuit is relatively easy. As mentioned in post #3 I suggest looking into using a MOSFET(a type of transistor) instead.

1 Like
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Alright, thanks, I will continue reading on this!

How much current at 5V does Arduino provide as a switch? Are there any other parameters to look out for?

It appears that adafruit has a MOSFET rated at high current (60A and 30V), I may need a heat sink (IRLB8721PbF)

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