We just bought a widebeam narrow boat which had a new Quattro fitted a few weeks ago. We understood that we would need to run the engine an hour or so twice a day to top up the Trojan T105 80ah 12v 4x battery bank which is our main source of power. We were briefly shown the bulk - absorption - float process and I’m sure we we’re told that we should turn the engine off when the float light comes on as it means the batteries are full and we could damage them by continuing to charge in float. When we turn the engine off, we have about 12.2-12.4v reading. However, over a period of several hours, running 12v fridge and freezer, watching Tv or charging devices, that goes down to about 11.4/6. Overnight, this causes an issue as our webasto heating system won’t start, presumably to avoid a flat battery.
Are we turning the engine off too early - Should we leave the engine running while in float for longer? And do we need to check that the Quattro was set up specifically for our battery bank - if so, how?