Alternator capacity | FerrariChat

Alternator capacity

Discussion in '365 GT4 2+2/400/412' started by SouthJersey400i, Jul 26, 2015.

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  1. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
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    Ken Battle
    #1 SouthJersey400i, Jul 26, 2015
    I took a recent 1000 mile 3-day trip. One the second day I had a 3+ hour drive with heat and rain. So besides fans, and fuel pump I was running with headlights, wipers and both AC fans running. We got to our motel and went to head to our destination and battery was near dead; it would not start the motor. I got a jump start and we drove less than a half hour with lights and wipers off with air on after getting going. Car started okay a few hours later. In evening did another 30 miles with lights on and air off. Battery never got a chance to fully recharge in this period. Battery was dead in morning and got a jump start. I tested voltage at battery and it was about 13.2 at idle and 13.8 at revs with no extra loads on, fans not yet running. We made it home with air on but no lights or wipers and battery was okay when checked after a couple of days. Both Alternator lights were always out when running, even at idle.

    Conclusion: my alternators in current state charge but do not have enough capacity for max. electrical load the car can dish out.

    Has anyone had the same experience?

    I have checked the alternators at various loads and engine speeds and they only give 14+V at raised revs and low load. With fans and lights on at maybe 2000 RPM I get 13.2-13.6. The upper alternator gives slight lower numbers than the lower.

    Do any of you get 14+ V with lights and fans running?

    I have previously (3+ years ago) replaced the brush / regulator pack on both alternators and plan to change one at a time and retest. Does anyone think the alternator itself needs to be replaced?

    Is there a higher amp "drop in" replacement for out alternators? Make and Model?

    I look forward to your responses as always.
    Ken
     
  2. samsaprunoff

    samsaprunoff F1 Rookie
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    Sam Saprunoff
    #2 samsaprunoff, Jul 26, 2015
    Good day Ken,

    Your battery voltages looks fine to me... Given the scenario you described, I would be more suspect of the battery itself. How old is the battery? Secondly, I would also be checking the battery capacity, as maybe your battery is a bit too light for the application?

    Cheers,

    Sam
     
  3. Ak Jim

    Ak Jim F1 Veteran
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    #3 Ak Jim, Jul 27, 2015
    What does the amp gauge show?
     
  4. SouthJersey400i

    SouthJersey400i Formula 3

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    #4 SouthJersey400i, Jul 27, 2015
    It is 2 years old and largest Amp Hour one NAPA sells, usually in a MB. I will get it checked.

    No amp meter in car; I think I can rig one at battery.
    Ken
     
  5. bundas

    bundas F1 Veteran
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    #5 bundas, Jul 27, 2015
    The batteries are just not as good as they were. I have to replace them way more often than necessary. Price is king. Quality is not.
     
  6. DaveO_48

    DaveO_48 Karting

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    #6 DaveO_48, Jul 27, 2015
    Ken,
    I was checking the re builder's number for the one of the alternators and it is used in a Fiat 124 Sport Spider, I think, and the Fiat guys have a drop in 95 amp replacement for their stock alternator. I believe it's nearly double the output as our oem alternator. If this is correct, there should be a way to swap the pulley and uprate the charging system. I don't know if it would require wiring changes, a different shunt for the gauge, or any other change but it does seem to me that somewhere lies an alternator change over that would solve the problem. Check into the reman # and see what other application uses it. Ferrari doesn't use a stand alone alternator.
    David
     
  7. Bill26

    Bill26 Formula Junior

    Jun 19, 2005
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    #7 Bill26, Jul 27, 2015
    The problem is the load/power capacity of the 7mm Powerflex drive belt.
    It's easy to find a higher capacity alternator but the belt can't handle the load - that's why 2 alternators on the later cars (with more electrical load).

    The OP's issue could be a slightly slack belt not handling the load.
    WM

     
  8. jacques

    jacques Formula Junior

    May 23, 2006
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    Los Angeles/Florida
    #8 jacques, Jul 28, 2015
    Please check all of the groundings in the car, plus the main alternator wiring. At nearly forty years old, the original battery wiring, both positive and negative have so much corrosion through the entire length of them, that their is substantial resistance to assure massive line drop. I replaced mine with #1 Marine cable, and just that alone was amazing. Of course, this is just a start. I have designed an entirely new set of fuse boxes for my car and will be installing it soon. As to the belts,Napa sell very good ones. Measure the belt Vee size and record the numbers on the belt and sort the belts in the store until you find it. The last few digits on the belt is the length,(cms or inches) so you don't have to remove the belt to buy the replacement I truly hope that this of some use. Thank you. Jq.
     
  9. SouthJersey400i

    SouthJersey400i Formula 3

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    #9 SouthJersey400i, Jul 28, 2015
    I like the idea of higher amp alternator for one of the two, maybe 60 and not 95A. I will check with International Auto that does Fiat and Alfa parts. I think it is possible to change one of the alternators to conventional belts without two much fiddling.

    I doubt the battery but will get tested and yes they ain't what they used to be, maybe an Optima or similar 'high end' will be better.

    I have done the grounding checks. My battery to chassis ground was spotless when I checked it after a starter issue. The plaque with the bolt was actually galvanized piece on chassis.

    For the moment, I know to shut something off on a long run. Multiple starts is not an issue which tells me battery is good.

    Thanks all.
    Ken
     
  10. bundas

    bundas F1 Veteran
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    #10 bundas, Jul 28, 2015
    Car before I shipped it. He should be able to tell
     
  11. DaveO_48

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    #11 DaveO_48, Jul 29, 2015
    Yes, they are both remans and work very well. I crossed the reman number ,which I can't remember right now, and it shows in some Fiats from 70's- 80's. And the Fiat guys have managed to upgrade them. I don't have the issue but a weak diode pack can seriously reduce the charging capacity, actually make it a drain on the system. I would prefer to keep stock appearing parts but if I needed a greater charging capacity, I'd start with the Fiat web sites.
    David
     
  12. Ak Jim

    Ak Jim F1 Veteran
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    #12 Ak Jim, Jul 29, 2015
    Another way to approach this is trying to reduce the load, maybe some LED headlights?
     
  13. bundas

    bundas F1 Veteran
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    #13 bundas, Jul 29, 2015
    I put LED's in the dash lights. At least the gauges cad be read at night
     
  14. SouthJersey400i

    SouthJersey400i Formula 3

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    #14 SouthJersey400i, Feb 25, 2018
    Upgraded my top alternator!
    Based on my alternator issues and same issues by other 400 owners i sought a logical permanent solution. I heard Bosch alternators could be upgraded to higher amp rating up to140 amp. Because of our skinny M belts i was not going to go for anything like 140. Rob at Centerline Alfa in CO indicated he had a top quality shop who could upgrade to any amp rating. I opted for 75 amps. I also opted to just do the top alternator for easy turnaround. Rob and his shop turned it around in about two weeks, quicker than promised. He used all new Bosch parts including new bearings, volt reg, etc. Cost $240.
    After reinstalling I gave it a good test today. With voltmeter connected i ran a series of test at idle and 2000 rpm. First no load then added high/low beam lights, interior fans, radiator fans, ac fans but no compressor due to low ambient temperature. Idle volts were down to mid 11's but 2000 rpm were all mid to high 13's. AND NO BELT SLIP at any condition!
    Having 45+75A vs 45+45 is about 25% increase and should handle all of the loads on longer trips.
    As soon as Finger Lakes weather warms up a road trip will be real test.
    Ken
     
    Il Tifoso and Part Time like this.
  15. Part Time

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    #15 Part Time, Feb 25, 2018
    Great news, Ken....let us know how it works, more amps will help everything on these cars !

    Gary
     
  16. SouthJersey400i

    SouthJersey400i Formula 3

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    #16 SouthJersey400i, Feb 26, 2018
    Rob at Centerline Alfa said I should check the alternator wires, he .has seen lots of green corroded wires. I tried to follow wires but lost them under left headlight pod. Can anyone tell us the route wires follow from there to battery?
    The reason I am optimistic about the 7mm belt taking the new load is that the belt has nearly 180 degree contact on the small alternator pulley.
    Ken
     
  17. Part Time

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    #17 Part Time, Feb 26, 2018
    Ken, the hot wires from both alternators do follow along with the headlamps, to the rear of the motor, to the firewall, sideways under the wiper linkage and end at the junction block behind the wiper motor, 3 wires on each stud, the other side of the block goes to the + battery terminal.
    PM me your mailing address and I can send you a 2 1/2 x 3 foot paper copy of my wire diagram .

    Gary
     
  18. SouthJersey400i

    SouthJersey400i Formula 3

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    #18 SouthJersey400i, Mar 2, 2018
    Gary
    Thanks for input on wiring, now I can start at the wiper motor rather than under the headlights.

    I made several large copies of wiring diagrams many years ago when I first started to tackle the electrical gremlins.
    Ken
     
  19. Part Time

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    #19 Part Time, Mar 2, 2018
    Ken, the two wires coming out of the alts headed to the batt are color code N, Black, not red......go figure...

    Gary
     
  20. miami355

    miami355 Karting

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    #20 miami355, Mar 20, 2018
    Ken, how did the alternator upgrade go? I noticed the other day idling for a long time, with newer higher drain stereo, all lights on, and fans kicking in I had a low voltage and it didn't want to re-start. I just called Centerline Alfa and am sending them pics of my alternator to see if they can rebuild.
     
  21. SouthJersey400i

    SouthJersey400i Formula 3

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    #21 SouthJersey400i, Mar 21, 2018
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    So far all good; I tested with lights, radiator and inside fans but too cold for A/C. I'll be doing first long trip in early April.
    If your alternator is a Bosche then Center Line can rebuild it. 75-80 amps seems okay with the small belts.
    Ken
     
  22. miami355

    miami355 Karting

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    #22 miami355, Mar 22, 2018
    Great! Are both upper and lower alternators the same? If that's the case, I may want to upgrade both. I have dual A/C (dual blower fans), and with temps in Miami, all the cooling fans will be on most of the time. These fans are 34 years old and I bet their AMP draw is more then when they were new.
     
  23. SouthJersey400i

    SouthJersey400i Formula 3

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    #23 SouthJersey400i, Mar 22, 2018
    Both alternators are the same, not sure about pulley diameter but that is no matter, they are matched to the driving pulleys.
     
  24. ag512bbi

    ag512bbi F1 Veteran
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    #24 ag512bbi, Mar 22, 2018
    This is a perfect thread I've been wanting to hear from.
    OK, This is the situation i'm having with my Daytona:


    Magneti Alternator & Regulator is charging around 14 - 15V, When engine is cold.

    When engine warms up to around 190, the coolant fans go on, The voltage drops to 12V at idle. When I increase RPM, the charge goes up to 14V.

    We checked out the Cooling fans, they draw 2.5 - 3 AMPs.

    As I continue to drive, AMPs continue to drop. Car eventually starts bogging (Low battery).

    ALT was tested. It's good. New Regulator has been installed.

    I believe that the ALT is NOT putting out enough AMPs.

    How much AMPs should my ALT be putting out?

    Is there an alternative ALT with a higher AMP that will replace my ALT?

    Or can my existing ALT be rebuilt to put out around 60 AMPs?


    Any advice will be appreciated.
     
  25. SouthJersey400i

    SouthJersey400i Formula 3

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    #25 SouthJersey400i, Mar 23, 2018
    Ag
    if your alternator is a Bosch it can be rebuilt to higher amp rating. Do you have one alternator or two? Our 400 series cars have two but also have lots of "luxury" items that eat amps. Our alt's are 45 amp each but 90 is barely good enough. To get your alternator upgraded all the info you need is in this thread; it takes about 3 weeks and $200.
    Ken
     
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