Review on HiLetgo Adjustable Step Up Constant Converter by Jimmy Breaux

After watching some videos on Youtube I got this to try to revive a Ryobi 40v battery pack that was no longer charging. There are no instructions, so you have to figure everything out yourself. There are also no meters for the output, so you'll need a multimeter so you can see the actual output while you make adjustments. I had to connect to an old laptop power supply (19V, 4.5A), had to try several times until the output was actually set to 40V. There is a faint click when charging, which is useful to know that it is working. It took almost an hour to charge the battery from 16V to 31V and it came back to life. The Ryobi Charger can now charge it normally again. The product description says that it increases heat dissipation when the output power is > 4A. In my case the output is about 2A at 40V. I put the module on a small metal box to better dissipate the heat, but after an hour the whole device felt hot (not just warm). Therefore, pay attention to heat build-up during prolonged use.