DC 24V/12V to 9V 3A 27W Step Down Converter Voltage Regulator Waterproof Car Power Buck Module

I live off grid and use solar power. I have a battery powered fan and d cell batteries were getting expensive. I hooked up this to my solar setup and used my fan 24 hours per day nonstop all summer!

This compact step-down converter has been working nicely for what I wanted it for. I have it attached to an 18-volt power tool battery to supply power to an old radio I take on jobs. It works much better and longer than the batteries I had been using. I tested the power on my multimeter before hooking it up to my radio and it showed to be reducing voltage from my 18-volt battery to 6.22-volts.

I was looking for a compact stepdown convertor to use in one of my 3D printers to power a raspberry pi. I've been running the pi off of a 5v rail from the printers controller board but the pi occasionally gives me grief about low voltage. Guess it's time to suck it up and do it more right. On my other printers with more space best practice here is to use a dedicated 5v switching power supply but this little printer quite literally barely has room for this step down. That's saying something too because this little step down is much smaller than I thought it would be, which is a good thing in my case. In typical fashion I tested new electronics first out of the intended device being used. Using a bench power supply it put out a pretty steady 5v output even as I oscillated the input voltage up and down. So much so I took it all the way down to find the point when the internal switching regulator effectively gives up. The floor seems to be with mine around 5.45 input volts before the output becomes affected. For many applications using a lower input voltage with a buck convertor doesn't pose a huge problem other than efficiency drops. The bigger risk here is depending on the switching regulator used here the duty cycle could run to 100%. If it is a serious concern for the operation of the circuit the designer would likely have some form of under voltage lockout where the convertor just won't turn on below a threshold. I don't know what that is or if it exists in this device as I did not drop the input much below 4.8v and it still stayed out albeit with a little over 4v on the outputs.I'm hoping this has a long life ahead of it and plan on installing it shortly. If there are any issues down the road with stability or life I'll try and come back here for an update.

Works well i get 6 volts

It comes as a very handsome and easy to use package. You would have to try to hook it up wrong. On my bench, I could get 5Vdc out of it all the way down to 8V input. But it would not output the rated current below 12Vdc input. This an excellent device for automotive use.But whether under a resistive load or not, I measured up to 10% ripple voltage, depending on the input voltage. It starts at 5mV at 12V input, and grows in both peak voltage and frequency as the voltage increases - up to 10mV @ 16V (where it no longer increases in voltage). However, it responded very well to a 220uF capacitor.So however you plan to use this, be prepared to add a smoothing capacitor to the output.