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BFL13's avatar
BFL13
Explorer II
Jan 03, 2018

Amps Rating 1991 Ford E350 Solenoid and CB Question UPDATE

Update--Some markings--go to 3 Jan post

I have an OEM battery solenoid between the starting battery and the house battery bank in the Class C. There is a DC CB of unknown amps size on the house battery side of the solenoid and another DC CB back by the house batts on that charging pos line from the solenoid and its CB. No size shown on that CB either.

Anyway, it says in the usual blurbs, that if you intend to upgrade your alternator charging amps, you also need to make sure this solenoid and the CBs can handle the higher amps.

So question is, how to know what amps they can do now when there is no amps marking on these OEM installed items?

BTW, as it is, starting up the voltage on either side of the solenoid is 14.92 today (it goes down later after running a while) so no sign of the reputed 0.2 voltage drop on a solenoid there.

Thanks.
  • Doubtful about your alternator style, thus it's potential. EVERYTHING is predicated on that. The IAR 75-amp, the 7074 70 or 100 amp, and 3G small and large frame alternators (95 or 130 amp) were used in those models.

    If you cannot take a picture and post it, stare at the alternator then compare with individual online google images.

    FORD 2G IAR alternator

    Ford large frame 100 amp alternator

    Ford 3G 95 amp alternator

    Ford 3G 130 amp alternator

    That'll make a good start

    Example this is the 100 amp large frame

  • What size is the wire between them? That might give some clue as to how large the breakers are, or would reasonably be. Also, are these the little rectangular self-resetting shortstop breakers, or some other style? The shortstop ones I think only go up to 50A.

    Typical solenoids I've seen available (for this general use) are often rated in the vicinity of 100A.

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