The "capacity at 5A is only 2720mah" is probably just a mistake in the datasheet. The discharge diagrams on page 4 goes up to 8A which is still close to 3500 mAh.
In this review the 5A discharge test was not as good, but still around 3200 mAh...
Any high power electric device should have a fuse to keep things safe. Lithium batteries can deliver a huge current thanks to their low internal resistance and if they overheat they can catch a volatile fire.
I would add a 30A automotive fuse in series to the red bypass wires just to in case...
If not the right procedure is used there is a high change of bricking the Shimano batteries. I only wanted to do a discharge test by connecting an electric load to the pack directly which resulted in some form of lock out / shutdown / protection mode.
The battery no longer turns on. I tried...