I am amazed by how well this hack works!
I installed this the cheap and nasty way.
Bought 4 x 12cm Ø cooling fans on bid or buy . co . za for R50 each.
Cable tied them together
Used an old 12v 2000mAh CCTV power supply and connected the 4 fans together.
I'm seeing approximately 15 degrees lower temperatures!
My inverter is installed inside a cupboard so I plan to use another 2 fans to push hot air vertically through the top of the cupboard. There is a ±30mm gap on the bottom of the cupboard so it should pull cool air in from the bottom and hot "exhaust" air to go out the top. Thus cooling it even further.