Safety:
First off, a hydrogen generator can be very dangerous if you are not taking the proper safety considerations.The tube producing hydrogen must be kept away from flames. I always keep a five-gallon bucket with water to place the tube in (as an added safety precaution). If safety precautions are not taken properly there is a potential risk of blowing up and sending PVC shrapnel everywhere. So safety glasses are required. Hydrogen is a useful tool but is very dangerous. You have been warned.

Disclaimer:
If you make a hydrogen generator from what I provided, I take no responsibility if you hurt yourself, others, or destroy property. Make at your own risk.

I plan to use this for an experiment to either run my generator off of hydrogen or create a hybrid system to see if my generator runs longer.

YouTube: https://youtu.be/7NqaH3yWsJw

I designed a hydrogen generator that I can run on my solar panels or on my solar generator. I used stainless steel washers and each 2 in washer alternated from positive to negative. I 3D printed a bolt to hold all the washers together. The hydrogen chamber is 4 inch PVC and the safety chamber is 2 in PVC They are held together with 2 3D printed pipe holders and there is a 3D printed stand. I use potassium carbonate as my catalyst.