Reddit reviews DROK DC-DC Voltage Buck Converter Volt Regulator 5V-30V to 0.8-29V Step-down Transformer Power Module 5A Constant Adjustable LED Dual Display Amp/Volt Ampere Ammeter Voltmeter Current Volt Tester
We found 2 Reddit comments about DROK DC-DC Voltage Buck Converter Volt Regulator 5V-30V to 0.8-29V Step-down Transformer Power Module 5A Constant Adjustable LED Dual Display Amp/Volt Ampere Ammeter Voltmeter Current Volt Tester. Here are the top ones, ranked by their Reddit score.
Dual display of voltage and current; within 5A constantly adjustable output voltage and output currentIt adopts high-quality LED which is visible and easy to read even under sunshineHigh-quality chip is used to ensure high efficiency(95% Max), small heating generator and stable output performanceBlue LED indicator lights on when the meter is charging while red LED lights on when the meter is full-chargeShort-circuit output terminal, then adjust the current output, you can set the current limit.
Yeah, that will create a lot of heat. Q2 is operated in the linear range to create the necessary voltage drop. If you want to be able to run at 10 V, then at 14.5 V it will be dropping 4.5 V plus the minimum v drop off the transistor. If your LEDs need 2 A that would be over 9 W.
A better approach would be a switching regulator that has a current limiting capability.
http://www.amazon.com/gp/aw/d/B00GZG7X9Y/ref=pd_aw_sims_1?pi=SL500_SS115&simLd=1
So you're handy with a soldering iron, and you slow the fans with resistors? Is there a reason you're not using an adjustable switching power supply to feed them, or a pwm?
http://www.amazon.com/DROK-Converter-Regulator-Constant-Voltmeter/dp/B00GZG7X9Y/ref=sr_1_1?s=electronics&ie=UTF8&qid=1425620423&sr=1-1&keywords=DROK%C2%AE+DC-DC+Converter+Buck+Regulator+5V-30V
http://www.amazon.com/DROK-Controller-Control-Electric-Stepless/dp/B00CGXJSNY/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1425620612&sr=1-1-catcorr&keywords=DROK%C2%AE+PWM+Controller+DC+12V+to+40V