For those of you asking how 1 XSPower battery would perform in a diesel application:
I recently replaced my 2 stock flooded style batteries with 1 used D2700 battery (stock size, group 27) The truck is a '95 Dodge 2500 with the 12v Cummins engine.
Voltage drop on start up with 2 stock batteries:
After replacing them with 1 D2700:
Notice that the (2) stock batteries performed worse than (1) D2700. The single D2700 did .6-.8 volts better on cranking!
Showing it is a direct replacement, even works with the stock hold down:
Stay tuned, I will update this thread as time goes on. It will be a long term, daily driver test, including sub-freezing starts...