Alternator size question.

jmbass98

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I bought a new wiring harness from M&H. What size amp alternator will the original wiring harness support? Or will I have to change wire gauges if I want to upgrade to a higher amp alternator?
 

Crash520

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How much current is your system drawing and what are you planning on installing over and above what you have now? The original system and for which the M&H is as it’s the same as factory is probably only good for 45-50 Amps on a good day! I suggest you do the bypass setup in any case. That said and as a guide, I don’t have any stereo amps but I do have and EFI system, electric fuel pump, with lights on high beam and everything running I draw 48Amp.
 

dvw

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I've run a 110 amp on the factory harness for 17 years. The firewall connections were cleaned. Dielectric grease applied to all connections.
Doug
 

Nacho-RT74

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Wiring size is more related to the car load demand and each of its accesories than the alternator ouput capacity. The alternator capacity just will guarantee the capacity to source the car ( and battery charge speed ) without battery asistance

you can check this with your own battery, which is able to feed either the starter motor with the 2 or 4 gauge wire, than the glove box light on a 18 or 16 gauge wire, while the batt capacity is the same for both.
 
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MoparLeo

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383man

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Remember the alt will only put out what the car and battery needs. You can put a 200 amp alt on a stock wire harness and as long as nothing was added to the cars electrical system the voltage regulator will limit the alt to only put out what the cars electrical load is and what the battery needs to stay charged. So if a car had a 38 amp alt and it supplied the car a 100 amp alt will only supply the same because its not demanding any more. But if you add electrical loads then the alt will put out more to handle the loads and then you may need to upgrade some wiring. Ron
 

70chall440

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I usually run a 120 especially anything with EFI and/or a MSD ignition. EFI likes power and wants clean power. Of course if you are going to run power fans, big stereo, etc. you need more than stock.
 

F4R/T

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Just make sure your wiring is up to snuff or it may roast something..Use heavy wire for the alternator feed if you increase your amp output and go directly to the battery. Others may offer other idea but don’t skimp.
 

Nacho-RT74

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Higher amp alt, (60amp) larger gauge Fusible link....
yes, but no. Once again, more related to the car accesories and load demand related to these. Actually if your batt is never sucked out, you could live with same fuse link forever
 

Nacho-RT74

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Just make sure your wiring is up to snuff or it may roast something..Use heavy wire for the alternator feed if you increase your amp output and go directly to the battery. Others may offer other idea but don’t skimp.

no
 

RJRENTON

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yes, but no. Once again, more related to the car accesories and load demand related to these.

"Actually if batt is never sucked out, you could live with same fuse link forever"
Once again a cryptic comment without any substantive documentation or explanation ...... what are you trying to say?
BOB RENTON
 

Nacho-RT74

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Already explained many times. Won't go on this again at least with the same ppl which I already have discussed about same topic.

Same reasons why the ammeter is safer with a higher output alt, the fuse link is ruled down same conditions. Same load going throught the ammeter will go throught the fuse link on any of both circunstances, charging or discharging. So, if the amm is rated +/- 40 and needle barelly moves with a good alt, fuse link will play on same rate, period.
 
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