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19-12-2017, 11:56
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#16
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16 N 82° 25.82 W
Boat: Pearson 422
Posts: 16,306
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Re: Overloaded 12v circuit with 24v
Just one more bit of information to make things clear.
If you connect batteries in series that is in a row one after the other, the voltage adds. So two 12V batteries in series will make 24V. Three 12V batteries in a series will make 36V.
If you connect batteries in parallel the voltage stays the same but you add amp hour capacity. Essentially that means it works like one, larger battery. So if you connect two 12V, 155 amp hour batteries in parallel it works like one large 12V 310 amp hour battery. Three in parallel works like one large 465 amp hour, 12V battery.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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19-12-2017, 12:14
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#17
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Registered User
Join Date: Dec 2014
Posts: 200
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Re: Overloaded 12v circuit with 24v
Ok thanks. The batteries are I parallel not series.
I burned the wire when I turned the isolating switch to introduce the battery to the circuit.
I connected the battery backwards by putting the terminal connectors on the wrong battery terminals.
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19-12-2017, 12:26
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#18
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,136
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Re: Overloaded 12v circuit with 24v
If the wire between the alternator and starter melted, it is possible that was a "fubisne link wire" which was once the industry norm, but is considered an unacceptable fire hazard today. In which case, it should be replaced with a properly fused wire.
If you're lucky the "alternator diodes" answer is the right one, and that will cost you a new diode assembly and internal regulator, perhaps. (I think I'd replace it regardless.) You might also want the starter opened and examined to make sure nothing in the coil windings got burned.
Eyeball EVERYTHING, and if anything else looks like it got melty? Consider replacing it.
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19-12-2017, 12:39
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#19
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Registered User
Join Date: Sep 2017
Location: nowra nsw australia
Boat: 32 contessa
Posts: 207
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Re: Overloaded 12v circuit with 24v
Personaly i would disconect all the batteries then conect just ONE so there is 12vdc then check everything works ,, with one battery conected you can start the donk and check the charging system , check the nav lights and radios ,
Good luck i hope you just cooked the fusable link , (a short wire that runs from the alternator ) ,,
Anyhow please keep us up to date ,
And dont be to hard on your self ,, i have been in the auto elect business for 35 years and i have done this ,,,,
Merry christmas , im sure santa will be kind and all is well
Rob .
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19-12-2017, 15:10
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#20
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Registered User
Join Date: Apr 2017
Location: Kansas
Boat: FP Salina 48, Hobie 33
Posts: 407
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Re: Overloaded 12v circuit with 24v
I think I've got a pretty clear picture of what happened. In order for there to be no fire and brimstone when he was connecting the batteries, he would have to connect the batteries in parallel to each other correctly. Then, he would have to make the last connection to the boat incorrectly. Reversing a parallel connection anywhere else would have resulted in an immediate meltdown of the battery cables and batteries, and may have included a phone call to the fire department.
With the polarity reversed to the boat, as soon as he turned on the main switch the alternator diodes acted as a short, and melted the wire and/or fuse link between the alternator and starter.
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19-12-2017, 15:22
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#21
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Overloaded 12v circuit with 24v
Whoa!.
" They are 3 x 12v 155Amphr batteries in series."
Stop right there - disconnect everythiing and get someone who knows a little bit about elecrickery to sort it out and explain the basics for you.
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19-12-2017, 15:43
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#22
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Registered User
Join Date: Sep 2017
Location: nowra nsw australia
Boat: 32 contessa
Posts: 207
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Re: Overloaded 12v circuit with 24v
I think i have what he has done ,, there are 3 batteries ,, 2 already in parallel the third is still in parralel but has the +- on the wrong way ,, then when he flicks the switch he then joins them together so the 3rd battery shorts as its the wrong way around ,,, so i belive that the cable to the switch and the switch would have burnned ,, i believe the drama will be isolated to the battery banks not futher up topthe motor as the 2 original batteries are still conected propper <<
CONFUSION ~
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19-12-2017, 16:06
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#23
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Marine Service Provider
Join Date: Nov 2008
Location: Port Credit, Ontario or Bahamas
Boat: Benford 38 Fantail Cruiser
Posts: 7,047
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Re: Overloaded 12v circuit with 24v
I've stopped giving electrical advice on threads such as this because .....
1. We never get all the info we need to provide an informed response.
2. The OP is unlikely to understand an informed response.
3. Many responses are made by people who know little more than the OP and how is the OP to know the difference.
4. This is serious stuff and can be extremely dangerous, expensive or both.
Bite the bullet, hire an ABYC Certified Marine Electrician and hang over his shoulder.
__________________
If you're not laughing, you're not doin' it right.
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19-12-2017, 16:25
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#24
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Registered User
Join Date: Apr 2017
Location: Kansas
Boat: FP Salina 48, Hobie 33
Posts: 407
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by boatpoker
I've stopped giving electrical advice on threads such as this because .....
1. We never get all the info we need to provide an informed response.
2. The OP is unlikely to understand an informed response.
3. Many responses are made by people who know little more than the OP and how is the OP to know the difference.
4. This is serious stuff and can be extremely dangerous, expensive or both.
Bite the bullet, hire an ABYC Certified Marine Electrician and hang over his shoulder.
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Good advice.
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19-12-2017, 16:45
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#25
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16 N 82° 25.82 W
Boat: Pearson 422
Posts: 16,306
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by StuM
Whoa!.
" They are 3 x 12v 155Amphr batteries in series."
Stop right there - disconnect everythiing and get someone who knows a little bit about elecrickery to sort it out and explain the basics for you.
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After seeing the OP doesn't know serial from parallel I think hiring a pro is the best thing to do at this point.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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19-12-2017, 16:56
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#26
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Registered User
Join Date: Sep 2008
Location: Surrey, B.C. Canada
Boat: Passage 24/30 Cutter
Posts: 683
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by Tornadosailing
Good advice.
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DITTO!
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19-12-2017, 17:58
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#27
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,135
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by skipmac
After seeing the OP doesn't know serial from parallel I think hiring a pro is the best thing to do at this point.
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Umm... do YOU know the difference between serial and series??? Or did you mean cereal, as in wheaties?
(Just kidding, really... the OP does seem to be pretty naive on things electrical)
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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19-12-2017, 19:20
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#28
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16 N 82° 25.82 W
Boat: Pearson 422
Posts: 16,306
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by Jim Cate
Umm... do YOU know the difference between serial and series??? Or did you mean cereal, as in wheaties?
(Just kidding, really... the OP does seem to be pretty naive on things electrical)
Jim
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I think my fumbers got fingled.
Don't care about no serial batteries anyhow. All my batteries are wired in parallax.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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19-12-2017, 20:18
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#29
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Senior Cruiser
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,888
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Re: Overloaded 12v circuit with 24v
Quote:
Originally Posted by Jim Cate
Umm... do YOU know the difference between serial and series??? Or did you mean cereal, as in wheaties?
(Just kidding, really... the OP does seem to be pretty naive on things electrical)
Jim
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In context: the only difference is that correctly speaking, ones an adjective,ones a noun.
(And the adjectival form could well be the correct on in the previous post - "serial or parallel connection" v "connection in series or in parallel".
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19-12-2017, 20:51
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#30
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16 N 82° 25.82 W
Boat: Pearson 422
Posts: 16,306
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Re: Overloaded 12v circuit with 24v
My turn.
Serial could be a noun (a story published in installments in a periodical for example) or an adjective so both could be nouns.
And you forgot the apostrophe in ones [sic] where it's used as a contraction.
Quote:
Originally Posted by StuM
In context: the only difference is that correctly speaking, ones an adjective,ones a noun.
(And the adjectival form could well be the correct on in the previous post - "serial or parallel connection" v "connection in series or in parallel".
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__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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