I recently installed a solar battery maintainer on my XKR, so I was surprised after starting it for the first time in a week and a half that it wouldn't start!

Cranking it the first two times, the car would start and crank for quite a long time and then almost start, but then the car would stall and everything would fall silent. Finally it started, and after a few seconds, everything was running normal.

My first guess would've been low battery voltage, but there were no electrical gremlins to report (usually when I have low battery issues, the touch screen won't come on, shifting can be sorta jerky, etc.). Any other possible causes?

I have an OBD2 scanner so I will try to get a reading on the fuel pressure next time. The car is at the shop right now getting new tires put on so I can't do it now.