Sorry for my late entry, I just came across this thread in a Google search for something related...
We have been experimenting with packs from the same manufacturer since spring.
We previously were working with PHET packs, but found them to be a bit too pricey for what they offered.
We got our packs after the manufacturer had designed a new BMS for better balancing (from Justin's feedback to them). There have been a few other issues, such as one pack whose BMS was programmed with too low of a charge voltage, and also, the packs switching off due to large capacitor inrush (for those controllers with big capacitors). But aside from those issues, I've used these packs (one 37V and the other 48V nominal) every day for the last 3 months on my 35A BMC/CurrieUSPD setup with an Xtracycle, and I've had a very good experience. We've also had a few customers testing them.
Like someone else said, they are nearly indestructible - I dropped a 48V pack out of the back of my Xtracycle panniers when going over a curb, and it was unscathed. I've taken them apart, and they are pretty well built on the inside. Anyway, my 36V sample pack (which was a warranty replacement for the one with incorrectly programmed BMS), has carried me at least 800 miles and 5-8 kwh of use.
In terms of capacity, we've found the packs to have slightly less capacity than rated. For example, the 10AH packs we got are really about 9.5Ah at low current. The catch is that when discharging at high current rates as you draw close to the limit, you risk prematurely shutting down the BMS. It will shut down not only when overall pack voltage gets low, but if an individual cell goes below about 2.3V. So if you are drawing a lot of current and one of the cells hits that voltage, it is game over. In my case, I've just learned that for the last Ah or so, to take it easy a bit, in order to not get the sudden cut-off.
Since we've found the packs to be well constructed and the manufacturer very serious about fixing any issues, we will be carrying them in the future. We're now set up for programming the BMS (cutoff voltages and etc), and also with replacement cells. Also, the manufacturer is almost done with a new BMS board that addresses the capacitor inrush issue (they've already addressed the cell balancing issue).
One thing we are going to do with ours that are different than the ebikes packs is put a locking loop on them, so you could run a cable lock through it (for a battery that is over $500 a pop, theft could be an issue). Also, an inline switch. If there are any other suggestions for improvements, now would be the time, we'd be happy to incorporate them if at all possible.
Morgan
cycle9.com
