They both have chargers, Dan. I'd never buy such a dangerous battery without its dedicated charger.
Mounting frames for both will somehow have to be kludged onto the bike but the top model has a frame slotted along its entire length for use with bottle cage mounts (which is how my current battery is mounted) whereas the lower battery's frame will need holes or slots drilled and aligned.
In fact I thought both had USB ports which was why I shortlisted them but the vendor assures me only the top one is so blessed. I do have a use for a USB port: extending the range of my heart rate monitor, of which the Polar H7 chest belt/sender is self-powered but the display/controller is my iPhone, the battery of which is wiped in only a few hours on Bluetooth, even the low energy Bluetooth 4, so a USB on the bike battery will be handy in maintasining the usability of a mobile that doubles as an emergency phone. (I was recently looking into smartwatches that take your heartrate by a green lamp flashing against your wrist but there are difficulties with getting that reading into any of my software, or indeed almost any software. I think that in six months or a year, all the peripherals to make smart watches useful may have caught up.)
There's more: Besides the USB, the top battery has an on/off switch and an externally accessible fuse, as well as a very desirable 28A controller (100kph anyone, even if not for long?), none of which the bottom battery offers.
It's starting to look like all the bottom battery has going for it, considering that the price difference is almost zero and the batteries are within 5mm of each other in size, is a more integrated, smoother cosmetic design.
