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Question: Can this dc-dc power from a deep cycle 6V battery, and output steaty 5V to power Adsl modem? how about if input reach 7V when fully charged? Thanks!
Document: )Second, they will audibly oscillate when drawing more than about 1A from a higher voltage source. You can hear the high pitched whine if you have sensitive ears. This annoying feature can be mitigated by lowering the input voltage. * Third, and critical if you are operating on battery power: if your voltage source is substantially higher than the output voltage, this may burn a lot of amps even when the load draws little to nothing.
these little step down power units work as described and you can adjust the output to any DC voltage that is lower than your input voltage.
Great price! I was considering taking apart a couple USB lighter adapters to get a 12v->5v power supply and stumbled across these. The converter keeps Voltage very well over wide range of input voltages. I adjusted it for 5.001V with a 10V battery, then switch the input to 19V input and the it only changed by 2mV. I haven't applied too much load( about 100mA)  It drew about 3mA with no load.I ordered it directly from China (Kingkongmall) which took about two weeks.
I ordered this switching voltage regulator after classic 7805 turned out to heat too much due to too big a voltage drop (15V input). I needed higher input voltage to power the LCD. I wanted to use the same power brick for a constant 5V for Raspberry Pi. This product seemed perfect. Multi turn potentiometer allows me to set voltage precisely, down to a single mV. It powers Raspbery Pi and audio amplifier with ease.
Reliable and easy to use. I used this coupled with a Mini-Box picoUPS and a 12V battery to provide an uninterruptable power supply for a critical low voltage device, which was designed to run off a USB power adapter. It was easy to trim the voltage to match the required 5 volt output and now I don't have to worry about power failures - the device keeps on running.Construction quality was good.
I bought these to power a 10w  RGB LED. The voltage regulation was very stable for an inexpensive part. My DMM reported that with inputs at 3.3v, 5v, and up to 12v it was able to maintain a steady 3v output.I would've rated higher if one of the 2 hadn't arrived DOA, shorting out anything I tested it on. I initially tested it on a 9v battery. Within a minute, the battery blew up (top popped off).
I was using one of these to provide 12V to a cable modem from about 20V DC. Once I got everything dialed in, I soldered the wires in place, did one final check for polarity, voltage, and no-load current. Then I plugged the output into the modem. Long story short, the LM2596 failed shorted, and destroyed the modem, and the module. This is very disappointing because the load was only about 5W, or 12V at 420 mA - nowhere near the claimed specifications.
I purchased these for my ROV to provide 5 volt power for the FPV transmitter and 12 volt power for the camera and IR LEDs. I normally just use a LM7805 or LM7812, but with a 24 volt input, these would waste too much power in the form of heat. The Buck converter handles this perfectly and inexpensively. I recommend putting a drop of nail polish or some similar substance on the set screw once you have set it to the desired voltage.
This tiny power supply is ideal for 12 volt DC to 5 volt DC car battery to logic level conversion, which was why I purchased it. The application draws less than half the available power. Units arrived in a timely fashion, and were undamaged. The price for two units was phenomenally low!
While they are incredibly efficient* and handy (I use them to power some 12V computer monitors off of a 24v battery bank) they have a few caveats.First, don't let your voltage get low because rather than cutting off like you might hope they will simply keep trying to supply power at below the voltage level. This could damage some electronics, so use some sort of limiter (like a CJKIT-20462) to protect from low voltage if it matters for your application.
Answer: 6V battery voltage may not be high enough for 5V regulated output. For LM2596 input and output voltage difference should be at least 1.5V for a stable regulation.  If input reach 7V or higher does not harm regulater. It is even beter for 5V output regulation.