Simon_and_Tanja
Well-Known Member
Maybe not a classic problem but I review this forum each day and it's on a classic boat ...
I could not start the Yanmar 10HP lump yesterday evening. Battery charge appeared OK (12.6V) but not a click from the starter. All that happened on pressing the start button was the ignition buzzer was silenced for about 10 seconds. Prepared for this scenario I set about with the brand new spare battery (yet to be installed) and some jump leads. Jumping the new battery in parallel with the installed unit made not one jot of a difference and solicited the same response. However when the loose battery was jumped to the regulator +ve output and an earthy point on the engine - bingo - fired up first time.
The current set-up is a simple single battery (shared domestic and starter responsibilities) routed through a master switch which seems to control everything but the bilge pump. Once started (and I disconnected the jump leads) the regulator output was up at 14.3v but there was only 13.8v across the (originally installed) battery. Poses quite a few questions...
Why would it not start on the installed battery?
Why would it not start with the two batteries paralled directly?
Why would it start when the new battery was jumped to the engine but not when it was jumped to the original battery?
Where am I losing 0.5v between regulator and battery (there shouldn't be any diodes in a single battery set-up).
With the master switch closed, surely there should be no difference between jumping the spare battery to the engine or jumping the spare battery to the installed unit? My first thought is that there must be some poor connection between the original installed battery and the engine but I am interested if anybody has alternative scenarios or some advice on how to better diagnose the issue.
I shall rewire over the winter and install separate starter and domestic batteries but for the moment, unless I can resolve this issue, I am forced to carry a loose emergency battery and jump leads. I also lie awake at night worrying that the currently installed battery is knackered and given my Stella "weaps" in places, without the bilge pump things might get very wet indeed.
Appreciate the help.
Simon
I could not start the Yanmar 10HP lump yesterday evening. Battery charge appeared OK (12.6V) but not a click from the starter. All that happened on pressing the start button was the ignition buzzer was silenced for about 10 seconds. Prepared for this scenario I set about with the brand new spare battery (yet to be installed) and some jump leads. Jumping the new battery in parallel with the installed unit made not one jot of a difference and solicited the same response. However when the loose battery was jumped to the regulator +ve output and an earthy point on the engine - bingo - fired up first time.
The current set-up is a simple single battery (shared domestic and starter responsibilities) routed through a master switch which seems to control everything but the bilge pump. Once started (and I disconnected the jump leads) the regulator output was up at 14.3v but there was only 13.8v across the (originally installed) battery. Poses quite a few questions...
Why would it not start on the installed battery?
Why would it not start with the two batteries paralled directly?
Why would it start when the new battery was jumped to the engine but not when it was jumped to the original battery?
Where am I losing 0.5v between regulator and battery (there shouldn't be any diodes in a single battery set-up).
With the master switch closed, surely there should be no difference between jumping the spare battery to the engine or jumping the spare battery to the installed unit? My first thought is that there must be some poor connection between the original installed battery and the engine but I am interested if anybody has alternative scenarios or some advice on how to better diagnose the issue.
I shall rewire over the winter and install separate starter and domestic batteries but for the moment, unless I can resolve this issue, I am forced to carry a loose emergency battery and jump leads. I also lie awake at night worrying that the currently installed battery is knackered and given my Stella "weaps" in places, without the bilge pump things might get very wet indeed.
Appreciate the help.
Simon
