Hybrid E-Bike

I am very new to e-bikes and just recently purcased a 600 watt wilderness brushless hub motor kit for my bike. It runs on 3 12v 12 ah batteries. I know very little about electric. I want to increase the range and longevity of my bike/batteries, but do not wish to spend or have the cash for a 600.00 set of lifepo4 batteries. I do however have a bicycle trailer and was wondering about the feasibility of taking a very small generator and mounting it on my bicycle trailer and using that to keep the batteries charged. It sounds like it would work, but I am pretty electrically ignorant. I would like to know if anyone has tried this and if so, what components would I need to make this work. My trailer has a cargo capacity of around 150lbs., so I think this would easily acoomodate the weight of a very small generator and inverter.