Battery Upgrade on our 2015 25' FB Flying Cloud
I recently upgraded our batteries by adding 5" to the bottom of the battery box and replacing the standard batteries with two Trojan J305H-AC batteries - going from 160AH to 360AH!
I have to say the batteries JUST fit with almost no room to spare!
I went with the Trojans instead of AGMs as they are about 1/2 the price.
Total cost was $700 ($200 to get the welding done, $500 for batteries).