OK .. interesting Electrical issue.
Put my boat on charge last week, usual method of plugging a cigarette ‘plug’ into the DC accessory outlet, I then have a SMART charger, I leave it hooked up to.
Noticed yesterday charger still not showing 100% charged …. Hmmm.
Checked battery voltage – seemed fine, checked trickle current when charging seemed reasonable…. OK maybe charger faulty …. Tried it on another 12V battery, showing 100% charged and into trickle mode after a few minutes .
Puzzling … started making comparison current readings .. and thought I would need to remove battery and do some bench testing …
Then I found the issue …the Nav light was on, but being under the covers did not see it … my mate had put the plug into accessory socket, and the Nav light button is alongside it … he must have pressed rocker to on without realising it.
The small current drawn by the Nav light was enough to stop it reaching 100% charge … switched light off, and charger went to 100% straight-away.
Just shows how you can be looking for complex reasons .. and not always necessary.
Ah well . too windy today and at least this allowed me to mess about with boat for an Hr.