Review on 🔌 SMAKN 30W/5A DC Volt Converter Auto Boost Buck Solar Charger 5-30V to 6-50V 12V Battery Regulator with Enhanced SEO by Timothy Richmond

I am trying to charge a 12V lead-acid battery from a wind turbine with this regulator. Apparently I was too late with the return, but maybe the defective device can still be exchanged. I set the output to 13.8V with a lab power supply connected to the input. Linear regulation is good enough for input voltages below 13.8V, but very poor for higher voltages. This is not to be expected with a buck/boost converter. When connecting an ohmic load, the output voltage drops by approx. 40 mV with a 30 Ω load and to 7 V with a 20 Ω load. It should be a 4 ampere regulator. I hope it's broken because with such behavior it's useless!