We received the first prototype bike seat backrest today from our factory in China and overall we're very pleased. The backrest installed easily, was very sturdy and comfortable, and panniers were easy to hang onto the side rails of the backrest frame. There are some elements of the prototype to clean up, but overall it met all of our requirements and is very close to being ready to start manufacturing!
The factory did a great job packaging the prototype, almost too good in fact. It was triple-wrapped in bubble-wrap, then completely taped up. It took me almost twenty minutes to cut away all of the bubble-wrap!
We did some home-grown load testing to make sure that the backrest could support reasonable weight against it and it held up without a problem. We also filled a pannier with over 25 pounds of water and hung it on the side rail and there were no issues at all. It's very sturdy, and we have just a couple aesthetic elements to clean up to be ready for production.
As soon as the Chinese New Year holiday is finished the factory will start making a second prototype, accounting for all of our change-requests based on this prototype. Hopefully manufacturing won't be too far around the corner from there!
Remember, ALWAYS wear a HELMET!