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Alternator Wiring to Mystery Box on Beneteau

arf145

.
Nov 4, 2010
431
Beneteau 331 Deale, MD
I'm working on the charging wiring on my Bene 331 and while tracing the output of the Yanmar 3GM30F's alternator, I see that both wires from the alternator go to a little black Bosch cube maybe 1.5inches on a side. Two wires go out of the cube, one to the starter (presumably the ground), and, sorry, I didn't finish tracing where the positive went. Any idea what this box does? It looks like a relay.
 
Mar 11, 2015
357
Hunter 33.5 Tacoma, WA
I'm working on the charging wiring on my Bene 331 and while tracing the output of the Yanmar 3GM30F's alternator, I see that both wires from the alternator go to a little black Bosch cube maybe 1.5inches on a side. Two wires go out of the cube, one to the starter (presumably the ground), and, sorry, I didn't finish tracing where the positive went. Any idea what this box does? It looks like a relay.
My guess is an external voltage regulator.
 

NYSail

.
Jan 6, 2006
2,719
Beneteau 423 Mt. Sinai, NY
an isolator? the other wire may go to a separate bank. Did you look on the "cube" to see if there are any identification numbers. I had a similar set-uo..... one wire went to the battery for my bow-thruster and the other went to the starter and ultimately charged the house bank.
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Perhaps it starts the blower motor or closes the circuit on a battery combiner?
 

arf145

.
Nov 4, 2010
431
Beneteau 331 Deale, MD
I know I should have taken the time to get some numbers off the cube--next time.

Meanwhile, it seems kind of small for a voltage regulator and I haven't seen any combiner anywhere. No blower, weinie, but good guess.

I will trace the positive next time--I'm almost certain it will go to the "on" side of the battery switches.
 

arf145

.
Nov 4, 2010
431
Beneteau 331 Deale, MD
I looked around some Ron--are you refering to the thread about the blower relay? Could be my case, though it didn't occur to me because I have no blower. BTW, the mystery box is indeed a relay, that much I now know from doing a little deciphering of Beneteau's cobra nest of black cables (they apparently saved by using black for everything and relying on a red heat shrink at the ends of the positives, which doesn't help in the middle of the nest :)
 
Mar 11, 2015
357
Hunter 33.5 Tacoma, WA
I looked around some Ron--are you refering to the thread about the blower relay? Could be my case, though it didn't occur to me because I have no blower. BTW, the mystery box is indeed a relay, that much I now know from doing a little deciphering of Beneteau's cobra nest of black cables (they apparently saved by using black for everything and relying on a red heat shrink at the ends of the positives, which doesn't help in the middle of the nest :)
Can you post a photo?