By the time we got to 2017, the batteries were getting better - a lot better! After several years of secrecy, the first patent was filed for the adapter system and the idea was released in February 2018. Even then, you still could not just order a thousand battery cells off the internet and start building a battery! And the costs meant only a few people could afford to build a long range bike anyhow.
But the batteries were still getting better, faster...
So we built a few models of our better ideas and worked out improved engineering for the right solution, but waited to commit to a battery format.