Another battery question , ahem

Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
That's a new one on me. Combiners are simple relays, and unless the wiring is horribly undersized, or someone did it backwards by running the AO to the reserve bank and uses the combiner to recharge a depleted house bank, there should be no voltage drop. Or am I missing something? Wouldn't be the first time....:)
Stu, I was talking about the older style diode controlled combiners rather than the relay base combiners. With a diode combiner, the diode has a 0.6v drop across the diode so if you have internal regulation, the 14.2v that the alternator is cut to 13.6v at the battery. If you have a sense wire at the battery, it wants to see 14.2v at the battery so the alternator will not start clipping voltage until it hits 14.2+6 = 14.8v at the alternator. The new relay combiners are a better solution and I have one on my work bench. Now if I can just find that round-tuit!
 
Jun 24, 2014
80
Westsail 28 72 Long Beach , California
dlochner , you named it . I believe those cables were made from arc welding cable . Please trust me they are in good shape , haha all this talk about charred stuff makes me want to fire up the Q . Down to the boat to day and I'm happy to report all is good batts. floating at 13.5 , but now I'm nervous about those bilge pump tubes . Plus I pulled a AC receptacle face plate and found stranded wire and no wire nuts . I kind of laughed to myself because I'm sure that face plate hadn't been touched in 40 yrs .
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
Good that things are in better shape than they look. The 2 issues with welding cable are, the wire is not tinned and the insulation is not as oil resistant as marine grade wire. The problem with the firs issue is corrosion potential and with the second is degradation of the insulation due to oil, diesel, and dirt.

Back in the 60s and 70s nobody expected fiberglass boats to last forever. So, builders didn't take as much care in some of the systems. And for electrical systems, about all they were used for was lighting and starting the engine. Things have changed.