The stand arrived, and it's all I hoped for. I used it to hold the bike while I checked and adjusted my rear brakes.
I also decided that I like the 4s 10000 mAh batteries so much that I've ordered another set, because the 4s 5000 mAh batteries that I bought two years ago, are starting to weaken. As a rule of thumb, I expect a battery to last about three years.
Those 10000 mAh batteries terminate in an XT90 (every battery I bought up till now terminates in a 4mm plug and socket). So I've made up some adaptors because I've standardised n EC5 connectors for everything.
I like EC5s, because they're fairly easy to plug and unplug, but not so easy that they slide out without some effort. I need the ease of unplugging, because whenever I charge up these batteries, I first have to unplug the harness that combined three 4s batteries together into a 12s (50 volts), then plug in the charger. Also, a couple of times when I've come off the bike, my pannier falls off, and if the battery connector hadn't unplugged, it would have ripped off the wires. But each time that happened, the EC5s have unplugged, and I just need to plug it back in to get going again.
I also bought 10 meters of AWG 12 wire, because Hobbyking are selling it really cheaply right now. Also some more XT90 connectors, and some more EC5 connectors.