Back to the original topic of 9300 vs E1505 batteries, I just received my E1505 and attempted a battery swap. The good news is that both batteries fit and work in the opposing system. The bad news is that whilst they work, they are not recognised by the BIOS, and hence don't charge.
BTW, I'm pretty impressed with the E1505. The screen is great and the system performance is quite perky (especially considering all the bloatware installed by Dell). I still prefer my 9300 for the sheer size and gaming grunt vs the E1505 and the E1505 is the perfect decoy for my wife!