| Author |
Message |
christopher (12.91.3.219)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 04, 2002 - 7:52 pm: | |
my coach has a 12v alternator to charge the house batteries. its a delco one wire. does this feed need to be fused before i introduce it into the system? and does it matter where its introduced?
what should the wire size be?
thanx
christpoher |
Tom Caffrey (Pvcces) (12.146.33.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 05, 2002 - 12:25 am: | |
Christopher, you didn't mention what you need to know to figure out the wire size. You need to know the amps of the alternator.
Our coach has over 200 amps output, so we run 00 guage. A single wire alternator has its voltage regulator inside of it, and I've never seen a fuse in those circuits.
I hope this helps.
Tom Caffrey PD4106-2576 |
Earl-8-Ky (209.42.180.214)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 05, 2002 - 10:37 am: | |
I have a 65 amp 12 volt alt. on my bus for the house batts. I used a # 8 wire to the batts. Have had no problems. I feel that a fuse or breaker on each end is just good Insurence. |
FAST FRED (63.215.238.89)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 05, 2002 - 2:39 pm: | |
If you have a fuse or circuit breaker in the Alt output line , and for any reason it opens the circuit , while the alt is charging.
YOU LOOSE THE ALTERNATOR!!!
IF an alternator output needs switching , for some reason ONLY the good quality Marine rotary switches should be used.
They have a break , before break feature , where the field is opened , the heavy conections made , and the field restored.
Disconecting any alternator from its load , under load , is DEATH to the unit.
FAST FRED |
christopher (12.91.0.76)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 05, 2002 - 5:26 pm: | |
thank you all
christopher |
Tom Caffrey (Pvcces) (12.146.33.76)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 05, 2002 - 11:34 pm: | |
Fast Fred, while I agree that what you say used to be true, I have in more recent years run across some awfully tolerant alternators.
I've seen 12 volt alternators used to put out 120 DC without derating their output current, and the single wire units run without being hooked to any loads because of an intermittent connection without them showing any bad effects.
Even though I know this, I would take every precaution to prevent it, because you never know when there's going to be a bad regulator and then you might lose the diodes.
I'm also sure that the cases I'm talking about did not have a permanent magnet built in to start them, like some of the marine alternators do. I wouldn't be surprized if one of those would fry on an open connection. And those alternators are expensive.
For what its worth.
Tom Caffrey PD4106-2576 |
Mike Kennedy (64.12.105.34)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 06, 2002 - 8:33 pm: | |
Any of the Delco 10si or 12si marine style single wire alt. needs no fuse However some O.E. marine builders do install a fueable link inline.
Taffyman |
Earl-8-Ky (209.42.180.46)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 06, 2002 - 9:31 pm: | |
I would much rather lose a 65$ alt. than have a fire in my bus. That is the reason I say fuse both ends. |
Tom Caffrey (Pvcces) (12.146.33.95)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 06, 2002 - 10:51 pm: | |
If you just want to protect against fire, a fuse on the battery end will do it. This is because a dead shorted alternator self-regulates and will not put out much more than its rated current.
This means that even with a lead shorted straight to ground, you will not burn up your wire with the output from your alternator.
And if you don't have a separate regulator, there will be very little or no output if the single lead is shorted to ground. The regulator that is inside the alternator gets its power from the output lead.
Something that gets missed on these car type alternators is that they might be rated 65 amps and only have an 8 guage(40 amp) wire on them.
They can get away with that in car service because the car battery will not take the full output of the alternator for very long, so the wire doesn't have time to get very hot.
However, in bus or boat service, that wire should be at least a 6 guage, because the recharge may stay at full output for an hour or more.
Tom Caffrey pd4106-2576 |