TIHOOD Aluminum Heat Sink SSR Dissipation for Single Phase Solid State Relay 10A-40A

Testing these using a 25A solid state relay to control space heaters.And with a type-K thermocouple on the first fin below the relay plate of the heat sink...when drawing 6.8A it heated to 104.5F - not a problemwhen drawing 13.5A it heated to 150.4F - marginalThe relay has 1.1v across it when passing 13.5A. That translates to 14.85Watts. The relay definitely needs a heat sink at this power level.Having a tapered center pillar in the heat sink would not make much difference because the straight pillar is already a little thicker than the plate the relay bolts to.Although the heat sink is aluminum, copper is a better heat conductor. Even at that copper wouldn't make much difference because this aluminum heat sink's thermal conductivity saturates the entire heat sink. If you are going to draw more than 13A and dissipate more than 14Watts a fan would be advised unless you buy a larger heat sink.If you are going to draw more than 4A through a solid state relay, you will need this heat sink.

as advertised

I was using an Inkbird temp controller with solid state relay and a 1500 Watt heating element. After a few hours, the relay would not turn completely off, and was VERY hot. I cooled the relay off and it would work again. After adding the heat sink to the solid state relay, the controller and relay work exactly as expected.

As others have noted, the image shown for the black version does not accurately represent what is shipped. It shows a much thicker central spine & SSR platform. (The photo shown for the "silver" [aluminum] finish shows a more accurate representation of what is shipped. Unfortunately, like others, I based my purchase decision on the photo.) This is not a 'cosmetic' difference, but basic thermodynamics... a thicker platform and central spine are able to conduct more heat to the fins, keeping the SSR cooler. The image they're using shows a higher performance heatsink design...Based on reviewer Mark Volkomener's data this heatsink appears to be about 2.8 C/W (or higher) with thermal convection. At 13.5A, Mark's SSR measured 1.1V drop, creating 14.85W of heat. For a constant-on application, this means this heatsink would create a 42C temp rise above ambient (67C or 152F @ 25C ambient). This also means 18A would push the SSR to 80C (a typical max temp for an SSR). One caveat: A 1.1 volt drop sounds low for a typical SSR output and is probably not worst case. (My SSR specs 1.6V max). Based on this, I would not push this heatsink more than 15A steady-state without forced air cooling. You can do the math if you have a less than 100% duty cycle.

Added these to my SS relays, just in case.

I bought these as an add-on to our 40-Amp Sold State Relays using in our on-board electrical system. They fit the "Fotek" relays perfectly, and do the job they are designed to do.

I attach 50W COB LEDs to these to make vegetable grow lights and they work perfectly for that purpose (great for use with lettuce). The 50W COBs do produce enough heat where you will need to attach a fan to them, but as a general rule you will always want to use fans with heat sinks.Great product, good price for US based shipping.

I installed these on some 20A solid state relays and they seem to be keeping them nice and cool. I'm running around 15A per relay.