sailorbenji
Active member
The battery is 4 years old, but I suspect it's been abused. I believe it failed, as I wrote in an earlier post, because possibly the boatyard left the engine breaker on for an extended period of time whilst we have been on the hard. With the breaker on, there is an unavoidable small draw on the battery from the engine ECU etc.
This wouldn't have been an issue if rectified in reasonable time (weeks even), but over the winter it's quite possible the battery maintainer kept the battery topped despite the vampire drain...at some point though, the maintainer would have pulled the 24V bank below its cut-off threshold, thus stopped charging the 12V battery and the vampire drain continued for who knows how long....maybe until 2-3V even.
At some point, it's been corrected, shore-power plugged in prior to relaunch, and the 12V maintainer has brought the battery back up to reasonable voltage (albeit very very slowly at 1.5A max, thus not exposing the heat issue).
As said, we have the ability to jump the engine at any point, we have the ability to split the 24V bank (now learned), what I didn't have was knowledge of what would happen running an alternator with no load......mea culpa.
Comparing cars on the road to boats isn't exactly a comparison. Most cars are used daily and as we all know, it's the times a boat is not in use for extended periods that issues tend to happen, especially if shore power is intermittent, or absent.
I would argue plenty of people with weekend cars, summer cars, or multiple toy cars, have issues with their batteries if, for instance, they just leave the car in storage, or the trickle charge set up they have fails for whatever reason.
That's simply what's happened, I believe.
I can't exactly swap our entire boat over to 12V, not that it would be a good idea anyway, in case we have another (once in 20 years) 12V internal battery short. It's been a 24V / 12V system from new and thus practically every piece of equipment on board is 24V.
This wouldn't have been an issue if rectified in reasonable time (weeks even), but over the winter it's quite possible the battery maintainer kept the battery topped despite the vampire drain...at some point though, the maintainer would have pulled the 24V bank below its cut-off threshold, thus stopped charging the 12V battery and the vampire drain continued for who knows how long....maybe until 2-3V even.
At some point, it's been corrected, shore-power plugged in prior to relaunch, and the 12V maintainer has brought the battery back up to reasonable voltage (albeit very very slowly at 1.5A max, thus not exposing the heat issue).
As said, we have the ability to jump the engine at any point, we have the ability to split the 24V bank (now learned), what I didn't have was knowledge of what would happen running an alternator with no load......mea culpa.
Comparing cars on the road to boats isn't exactly a comparison. Most cars are used daily and as we all know, it's the times a boat is not in use for extended periods that issues tend to happen, especially if shore power is intermittent, or absent.
I would argue plenty of people with weekend cars, summer cars, or multiple toy cars, have issues with their batteries if, for instance, they just leave the car in storage, or the trickle charge set up they have fails for whatever reason.
That's simply what's happened, I believe.
I can't exactly swap our entire boat over to 12V, not that it would be a good idea anyway, in case we have another (once in 20 years) 12V internal battery short. It's been a 24V / 12V system from new and thus practically every piece of equipment on board is 24V.
