DC Boost Converter, XH-M411 DC 3-35V to 5-45V Output Voltage, Adjustable Step Up Voltage Regulator Module for Solar Panels

Very reliable

I bought it to use it as a manual charger for defective Ryobi 40v batteries. Some of them refuse to be charged by Ryobi charger due to control board error or because of being discharged below a certain voltage. This DC to DC converter just pumps out required voltage from the output end without running any checks or asking any questions. This simplicity is a beauty! I had to use my old laptop's 19V 5A charger to provide an input that was successfully boosted by this converter to 42V to make it compatible with Ryobi batteries. It worked like a charm!

Works well, voltage range matches specification data. Did not do full performance testing (no load, ripple, nor transient load testing). Voltmeter works (push button toggles between input and output reading). Voltmeter is 0.7% off nominal, there is NO calibration adjustment. Build quality is very good.

I had a Ryobi 40v 2.6a battery that was not charging. After watching a video on youtube, I said to get this converter to "revive" the battery. I followed the steps and this worked like a charm. the only thing that took getting used to was the boost, and twisting the voltage up. There was a slight delay and do not know if that is common but worked perfectly! It was easy to use and easy to setup!

Not packed very well just in envelope which isn't good for PCB with parts sticking up as it arrived with heat sink broken off . Tried to use it could not get more then 28V output and both in and put screw terminals move when tightening screws so have to re solder connections. Will try it again but price was low I guess that is what you get

Using this to revive supposedly "dead" battery packs that have sat too long without using for my DeWalt tools. Open case, connect to battery bypassing the BMS, charge cells, short the reset pins, battery works again.

This seems well made but mine arrived in very minimal packing and the heat sink had gotten knocked off. If you have some heatsink paste/glue that's not a big deal (unfortunately I don't). More importantly, in testing it out I find it has a very dangerous behavior: if the input voltage falls to the range of 3.0 - 3.5 volts, the output jumps way up to 30 or even 50 volts! A moderate load (100 mA) seems to prevent this. I know it's not designed for that input voltage range but one hopes that if the input is too low it stops working in a benign way. I can imagine lots of situations with a light load and a battery running low where this behavior would be unexpected and disastrous. I read many reviews of another similar device with the same kind of behavior so I don't think this is my mistake or a faulty device. I think this is a design error.

These are great

It came on time works grate powers my device ok