Someone sent me a PM asking about the bag but I thought it would make sense to put my comments on the public forum.
I've had the bag for a few weeks now and it's been great. I am happy with the way it fits in the triangle yet doesn't get in the way. My 48v15ah ping just fits... barely. The velcro straps that keep it in place seem to be very durable and should last a long time. There are a total of 9 straps to hold it securely. I went straight from a front-hub motor and battery on the rear-rack to a rear-hub motor and traingle mounted battery. The bike seems to handle well. I am noticing that I can lean a little more in turns.
I'm a little concerned about the strain of the straps on my brake/shifting cables, which run along the top of my top tube. The rear deraileur cable also runs down the seat-tube. The weight of the battery in the bag puts pressure on the cables, but I have not noticed any issues in practice, but I may replace the cables a little more often than normal if this causes them to stretch out over time.
My only real complaint is the amount of time it takes to attach and detach the bag from the triangle. I used to have my battery in a different bag and it took about 10 seconds to place it on the rear rack and affix the necessary bungees. Now, it takes over a minute to secure or un-velcro all of the straps. I live in a high-rise and need to remove my battery daily to take it upstairs to charge. I also remove it when I am out and need to leave the bike locked outside for more than a minute. For someone who is able to keep the battery on their bike, this is not an issue.
This extra time to mount and dismount actually makes the battery slightly more theft-resistant, because it would give you more time to catch a theif in the act, if they don't just give up after one or two straps. I would still like to find a way to secure the bag to the bike in cases where I want to leave it locked outside for more than a few minutes. The zipper pulls have holes for a small lock to prevent people from easily opening the bag.
I covered the FalconEV logo with some black duct tape. Crude, yes, but I don't need the attention that the green embriodered logo would attract.
A simple carrying handle would have been a nice addition, but I've been able to get by holding a few of the velcro straps or just holding the whole bag. The mesh side-pockets came in handy last week when I had to have easy access to a map while following the Chicago Marathon. The pockets may also be a convenient place to slide in some protective material instead of putting it in the bag.
Overall, for a little under $50, this is a great bag and I highly recommend it.
2001 Trek 820 / 9c 2806 rear / Infineon 22a / Ping 48v 15ah
Unbranded full-suspension folder / Bafang 24v rear / 24v Li-ion