Prostar battery APU shuts down too fast

[Nilao]

I had a nite system in a freightliner many moons ago. It'd last around 8 hours if the night was in the 70's. Less than 6 if it was 80+. Those systems tend to take them to the bottom as far as charge goes. Like 80% discharged. Lead acid deep cycles can go around 800 cycles at that discharge rate. Of course there is diminishing returns ...meaning as you cycle it it can no longer get back to 100% of its Amp hour rating. It looses a percentage of its rated capacity every cycle. If I had one today I would use 4 lifepo4 batteries in its place with a separate battery charger that charged them off the main bank.