J’ai trouvé la réponse à mon problème :

« Keep in mind that many marine alternators are case grounded and thus the system ground, which on most boats is the engine block, is the ground path for the alternator. While I much prefer an isolated ground for alternators many boats just do not have alternators with this feature and they use the case as the ground. Due to this, the ships main ground connection should be connected to the -LOAD side of the shunt and NOT ahead of it or on the -BATTERY side. »"

extrait de http://www.pbase.com/mainecruising/...

Merci de vos réponses.

Jean