Alternator, need to get to the bottom of this.

Interior and Electrical

  1. Bruceynz

    Bruceynz Well-Known Member

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    Hi Guys,

    Ok a while ago I had some issues with the fusible link to the Alternator burned up, so as a quick fixed I joined it back up again and it has worked for a while, took car to work today and the alternator light was flicking on and off, got to work to find the fusible link had popped again. So after work in the carpark I put a piece of wire in there and before you say OH NO YOU CAN'T DO THAT from all my research a fusible link is nothing more than a piece of wire smaller than the wire used in your car with a special rubber coating that doesn't burn, so selected a piece of wire of lesser gauge than the main wiring. Note the battery has a hydrometer built in and its black/green/clear, the battery was showing black which means its in need of charging. Put my meter across battery and its 12.68v, start car up and check wire is not hot and it was ok, put meter across it and rev car up and comes up to 13.2v, that's not enough to charge, I remember my father years ago saying Chrysler charging systems are weird and he could never work them out, so I get home pop the hood and the blue wire is melted, put my meter on and its now charging at 13.9v when you rev it up, so that's more like it! maybe 14.2v would be perfect. Now the charging system is either clever than I think or Chrysler has a weird system, anyway I am thinking this, the alternator is not the one that came off the car, I noted the other day you can get a couple Alternator options on current for your car, could be wrong here but I think it was like 60,80 and 100, I have no idea what the Alternator I put on is can't find specs on it. I am suspecting Chrysler set up the fusible links to what Current Alternator is fitted in the car, so my battery was getting a full charge into it and the current was more than the link could handle, that's my thoughts, everything in the car is working as normal.

    Old Alternator has a round yellow/bronze colored tag on it.

    This is the Alternator on my car now - Premium Quality Remanufactured Alternator mopar part # 3438713 5305 ~ 3035

    I have spliced in a 100amp fuse, I hope that is not to small. If 60 amp alternator that's all that can come from that line, if more current is required it will come from battery and the battery will go flat. Head lights 10amps, Ignition 7amps, radio, heater blower and rear demister, that rear demister could draw some amps, maybe 10/15amps

    IMG_20160822_220238.jpg

    Thanks
    Bruce
     
    Last edited: Aug 22, 2016
  2. High Speed Pursuit

    High Speed Pursuit Well-Known Member

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    Your current alternator is a 60 amp...if I remember correctly, our cars came with a 37 amp alternator with factory fusible links. Prior to 1980 there were no fusible links on the MOPAR charging systems...could be 5% wrong on that, but overall. I'm no electrician or anything, but I'm pretty sure that 100 amp fuse you installed will keep from blowing/melting, but its also gonna let your 35 year old wires that were made for a 37 amp (+120%) system get very hot and probably melt everywhere and anywhere except your 100a fuse. Me, I would back the fusible link down, install a solid piece of 4 or 6 ga wire from your fusible link from your alt to your battery...not patched in. In your photo it appears the fusible link has a heavier gauge wire pieced in...fusible link wire gauge should be 2 wire numbers smaller than what u are protecting, for example, a 10 ga system would use a 14ga wire...get more advice, but i can tell u that wiring harnesses for our cars are nearly impossible to find.
     
  3. Bruceynz

    Bruceynz Well-Known Member

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    Hi,

    In the 1983 Cordoba Sales Brochure it says Standard equipment is 60amp alternator. The 100amp fuse is in the alternator line, before the fusible links for the rest of the car are still the same, this as far as I know will protect the alternator from a direct short but will also let the alternator charge at max current. I could put a 60amp fuse in the line, this means if we were drawing 60amps for some time it could blow, but that probably would only happen if the battery was dead flat, heater on, lights on full and rear demister on.

    Thanks
    Bruce
     
  4. High Speed Pursuit

    High Speed Pursuit Well-Known Member

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    Sorry about that Bruce...I thought your car was an 80 also...my car is A/C delete but with a vent dash like it has A/C, and because of that I only got the 37amp alternator...yours will be a 55a or 60a depending on the info source. I have used this link as a reference from time to time...maybe it will help you with some part of your issue. Interpreting the Test Results For the Chrysler Charging System, 1970 - 1989
     
  5. Bruceynz

    Bruceynz Well-Known Member

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    Ok I will get to the bottom of it, is an issue between the alt and the battery not the bat and the rest of the car, that red wire I spliced in has a 100amp maxi fuse in it, I am going to look more harder at the alternator tonight.
     
  6. kkritsilas

    kkritsilas Well-Known Member

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    Twp things to keep in mind:

    1. The charging system, and by extension, the fusible link, are sized according to demand. That is to say, the fusible link is sized according to expected load, not according to the Alternator. No matter how big the alternator is (assuming it is at least big enough to provide enough power), a fusible link will not blow until the current demand exceeds the rating of the fusible link.

    2. Understanding that, whether Bruceynz has a 37, 60, 80, or 100A alternator is somwhat irrelevant. What is blowing the link is a load that is exceeding the current rating of the fusible link. More than likely, Bruceynz needs a new battery. I personally suspect that he has an intermittent short in the battery circuit, and the most likely culprit is the battery. Something like a cracked plate moving around under vibration and shorting,, or metallic sediment at the bottom of the battery shifting around while he drives the car and shorting.

    How old is the battery in the car?
     
    Last edited: Aug 22, 2016
  7. Bruceynz

    Bruceynz Well-Known Member

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    I have not been able to find out what current(amps) the Alternator fusible link is rated at yet. I fuse is a protection device and is designed to protect if there is a short circuit. An Alternator can only charge at full current if the battery is very flat, most of the time the alternator gives it a we top up and then runs the lights, heater etc

    I had another post about link fuse wire and did find this

    Fusible Links

    Circuit Hypalon Link Type MAXI Fuse Rating Circuit Wire
    Alternator Feed (R6) 12 gauge (black) 160 amp (2x80 in parallel) 8 gauge (BK)
    Radiator Fan (C26) 20 gauge (orange) 40 amp 14 gauge (GY)
    Ignition Feed (J10) 18 gauge (grey) 50 amp 12 gauge (PK/BK*)
    Ignition Feed (J1) 20 gauge (orange) 40 amp 12 gauge (RD)
    ECU/ASD Feed (J1) 22 gauge (white) 30 amp 12 gauge (PK)
    Direct Battery Feed (L1) 18 gauge (grey) 50 amp 12 gauge (RD/WT*)
    Heated Rear Window (C13) 18 gauge (grey) 40 amp 12 gauge (BK/RD*)
    Hazard Flasher (A3) 20 gauge (orange) 20 amp 14 gauge (PK)
     
  8. kkritsilas

    kkritsilas Well-Known Member

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    All true. But your fusible link and work around have both melted. Something on the load end of the fusible link is shorting, or at the very least, presenting a current demand higher than the fusible link is rated for. It is most likely a bad battery.

    Put it another way: I go out and get one of those Car stereo monster alternators (250A maximum output). My Miranda is a factory 100A alternator. I replace the 100A alternator with a 250A alternator. If I do not have any shorts, none of the fusible links will blow, neither will the fuses.Voltage will increase a bit, depending on how well the regulation is set up on the car, and that is all.
     
    Last edited: Aug 22, 2016
  9. Bruceynz

    Bruceynz Well-Known Member

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    Took alternator off tonight, diodes measure ok, didn't think it was going to be a diode issues, dead diode means less output. Can't see anything around the alternator, no swarf or metal around there that could cause any issues, hooked multi meter onto to alt power wire and one to earth and wiggled it around and it didn't short out anywhere. I do run a battery isolator and my neighbor who is Canadian and goes backwards and forwards all the time said that he had one of those isolators and caused some restive coating between the bat terminal and the post and caused him to have issues with his alt as well.
     
    Last edited: Aug 23, 2016
  10. Bruceynz

    Bruceynz Well-Known Member

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    Well I have put my old alternator back on the car, when i had it on my work bench I noticed it was unbalanced when you spun it by hand, not sure how this would manifest itself when its spinning at 5000 rpm, my old alternator was out of balance as well but no where near as much, has anyone else spun a Chrysler alt by hand and noticed this?

    Will get the car cranked up over the weekend and see how we go with the 100amp fuse and the old Alternator, I just wonder if some how the new alt with RPM on it could of shorted out because its unbalanced. My alt was one I bought on ebay that was rebuilt.
     
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  11. Justwondering

    Justwondering Well-Known Member

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    thank you for swarf! I've never heard that term before and it is totally accurate. I've used a drill press and all those metal filings i could have been calling swarf. Love it.
    thanks again. You guys totally rock
     
  12. Bruceynz

    Bruceynz Well-Known Member

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    Swarf I dunno, is it an English term only and you guys in the USA call it something different, lots of stuff like that goes on, NZ is in the Commonwealth like Canada, but we have had a lot of USA influence over many years, lots of people love USA cars including me!! 60 and 70 muscle are popular! Vettes and Stangs!

    Dunno if you know but the USA sent a lot of soldiers here to get better during world warII and the USA soldiers helped a lot in NZ to build roads and things here in those years. Also believe the NZ girls loved the accents and a lot of romance blossomed with the USA soldiers.

    For example -
    USA NZ
    Hood - Bonnet
    Trunk - Boot
    Windshield - Windscreen

    and OMG your spelling, tire - Tyre, Check - Cheque, Color - Colour, I just make sure when I post on here I use all the USA spellings so there is no confusion. Oh and for good measure there is 2 gallons USA and IMP and for great stuff to really mix things up USA car makers now use metric and imperial bolts on engines. Played with a we Chevy V6 Vortec in my boat and it has mixed threads. Metric bolts have an M stamped on them from memory! Fantastic! Just what we need :)

    See You
    Bruce
     
    Last edited: Aug 26, 2016
  13. Bruceynz

    Bruceynz Well-Known Member

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    Took my battery to what you would call the local Napa, it load tested all OK but what I did notice when I took the battery isolator off looks like it may have been causing problems.

    IMG_20160827_151019.jpg
     
  14. Bruceynz

    Bruceynz Well-Known Member

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    Fuse Size - Ok I have my fuses now, my choices are 60amp, 70amp, 80amp, 100amp or 120amp. Anyone wanna have a guess what size to fit in there, Alternator is 60amp so guess we don't want to be at that, I am thinking the 80amp one at this stage.
     
  15. BudW

    BudW Moderator Staff Member

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    For which exact circuit, will the fuse be for?

    I’m not sure how much current the power wire off of the alternator can carry safely.

    I do know putting a 100 amp alternator in place of a 60 amp one, can melt the harness down in no time, if you didn’t replace the wiring harness with bigger alternator wire, at same time.

    You want the fuse to blow before any damage can occur to wiring or anything else.
     
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  16. bremereric

    bremereric FMJ Body Moderator

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    You could also fry your amp meter. It is not made to handle 100 amps. Go to Spider Marine and get you a brand new 60 amp one. My lights were flickering at idle and I got a brand new one from them and it fixed the problem.
     
    Last edited: Sep 12, 2016
  17. Bruceynz

    Bruceynz Well-Known Member

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    So far so good, we are at 14.4v when the car is idling and when switched off the volts drop down to 12.6v, so thats good! No melted wires and no blown fuses. I have also upgraded the battery negative to the block earth wire as well, the factory one looked a bit on the anemic side. Fuse is 80amp. I have also got an earth strap on the other head to the fire wall, so should have good earthing.

    IMG-20160910-WA0004.jpeg

    IMG_20160911_154311.jpg
     
    Last edited: Sep 11, 2016