USB C PD to Step up converter for charging… basically no voltage output?

I’ve got this usb pd decoy. When plugged in, it works perfectly, handshakes and outputs 20V when set to that voltage.

I have a 10s battery, so I need a step up converter to get that 20V to 42V, so I bought this.

As soon as the converter is wired into the decoy, beds get shat :frowning: if the decoy is set to anything other than 5V, no voltage is output from the decoy at all. If I set the decoy to 5V, about 4.8V are outputted from the decoy and then the converter does its thing (seems to be set at 14ishV). It’s not meant to take less than 10V and it gets hella hot so it’s all a bit strange…

Anyone know what the heck is going on? Why’s the buck fucking up the decoy? Gonna plug the buck into a car battery tomorrow and see what it does from that, but figured I’d get a headstart on some hopeful responses here tonight :slight_smile: