how to wire an ALTERNATOR charging system on ANYTHING custom automotive wiring from scratch PART 2

car is a 1978 Datsun 280Z with an internally regulated 3 wire alternator

[@mike-yx7zd]

How does the voltage sensing work? How does the alternator not confuse its own 14 volt charging output with the voltage of the battery if they are electrically connected?

[@chriscraft77022]

i just make videos on how to make it work.. if you asked that question how would you understand the answer.. ? it works 100%, trust me

[@Walknpeace]

Best explanation I’ve seen after watching 7 videos.

[@richardalls2634]

That is the best video I have ever watched explain how to wire a car. I'm trying to wire a Cadillac DTS I'm having problems with and you just explain what I've been looking for on KZbin for three months thank you so much brother I appreciate you

[@Mike-zb7ts]

Your explanations are clear and easy to understand. Thanks man, you're saving me days of frustration.

[@mmpandflp]

Thank you very much. Great job explaining. Looking forward to your next vids.

[@duingstuff]

I love the way you explain how this works. I've been wrapping my head around adding a second dedicated alternator to charge a battery bank.

[@michaelbloom5342]

I am so glad you explained the diode/resistor/charge indicator lamp. When I put a Delco 3 wire alternator on my old 1958 Ford 641 tractor, I had that same issue, I couldn't get the thing to shut off without choking the carb! Wired in a charge indicating lamp on the dash, and boom, no more issues!

[@dbfcars]

Q

[@chriscraft77022]

thats exactly how i shut the first car off that would not shut off... scary stuff!!!!!!!!!!!!!!!!!!!!!

[@JohnsJohnson-ns5xm]

Great informative well explained video. I’ve always had difficulty understanding automotive electrical systems. This really helps. Thank you.

[@cockasorrus7475]

Thank you! Great info and presentation 🤙🏻

[@firstgenerationgarage2803]

Excelente job brother I learn this about 5 years ago watching 👀 one of your videos thanks

[@vicstevens2149]

Keep it up dude easy instructions what everyone wants!

[@dtperformance256]

Great attention to detail! Thanks for the video!

[@hippitydippity3331]

Have to agree with everyone here commenting, your explanation is spot on bro, I actually learned something here with the ability to replicate it. Cheers to you!

[@flyman1185]

Perfect explanation. It was simple to understand and believe me I need simple!

[@Mike-zb7ts]

Couldn't have said it better myself.

[@doncopple1769]

Great instruction! Very methodical approach

[@markblades4536]

Brilliant teaching Chris thank you

[@74satellite]

Those are pretty neat little cars I had one back in high school

[@jeffjeff-tl7yi]

You are a Wizard!!! Very Good video and explanation... I Thank You Very Much!!! Nice Car also. !!!

[@motor_citymuscle288]

Bro this videos are helping out a ton! Thanks!!

[@chuntzy]

Great video brother 👍🏼

[@UnkoHoloHolo]

Oh my Gosh, thats it, thats it!!! I recently dragged home. A previous owner modified, 1979 MG Midget Spridget. I been plagued with; electrical wiring issues, throughout the car. After i got it running, the previous owner was unable to do. Problems arose; when I decided, the factory wiring harness would not be appropriate to use. Thus I began to do what was my first forte with working on cars, at thirteen. Yikes, headache after headache came a knocking for a visit. And was hungry. Became stumped as to why; new batteries would drain, alternator would put out a small trickle that did not charge system. And, major iggy issues to boot. MG’s weather UK or US versions have interesting electrical engineering methods, in the grounding department. Chris the option your shared and showed. Woke me up. The lights came on. Your vid here, dusted much collected on cranium data I knew well. Now i can go do the proper hook ups and have a charging system, ignition running and starting present return to five star status. Mahalo nui loa, for this Chris. Other I know will be stocked to here what i will share, with parallel disfunctions. Chee Hu ✌🏽🤙🏽✨

[@VintRestGarage]

That was one of the best I’ve seen

[@beasyphone]

Jumping ypur VS wire to the stud surely works, but the best way to optimize /regulate your charging system is to get that VS wire as close to the battery as possible. Mine goes to the block on my inner fender directly beside my billet battery box on a 6" ish run. Here’s why using a remote voltage-sensing connection is a wise move. The main charge wire on the back of the alternator is eventually tied into the positive post on the battery. However, this connection is often a long wire. This cable length creates resistance that can be easily measured with a simple charging system efficiency test

[@Mr.FixIt98]

Thank you for being a great teacher bud. This is gonna help a lot on my c4 Corvette. Shit the way you drew that diagram made me subscribe and how detailed you were, keep at it bud

[@Knuckledragnation]

Alas a video simple enough in both explanation and drawing diagrams a neanderthal like myself can understand. No disrepect to all them high dig auto technicians in their fancy shops or those doctorates of electricity whatcha-ma-call-its out there and what not. Thank you sir.

[@dylan.indonusa]

Nice jobs , clear explanation 👍

[@alanyardley4832]

Excellent video, thank you!

[@mercmanwon]

Nice job explaining!

[@pmacc3557]

Wiw! You are blessed to have such knowledge and skill! I hope you are making a great living from this. Im searching KZbin on this topic as I have a 1983 Yamaha SR 500 Motorbike thats powered by alternator only (no battery so once you kickstart it into life you have electric power) and I want to upgrade to LED lights so want to add in a battery...but I am still not sure I'll be able

[@chriscraft77022]

motorcycles use a magneto.. i dont know anything about motorcycles.. sorry

[@martyjoseph9507]

Hopefully I can use this thorough explanation to make absolutely sure if my overcharging 1996 Mercury beater just has a broken wire or needs an alternator that would send it to the junkyard.

[@jasonrogers9169]

Torch lighter for shrink wrap works great! On solder also if its not a tight space

[@jacquespoirier9071]

for better charging performance, the voltage sensing wire should be tapped directly to the battery cable, otherwise, the regulator will not compensate for the voltage drop thru the charging wire and this can make the difference between a half charged and a fully charged battery.

[@joshferguson829]

I know this is a old post but can I do this on my 06 envoy on the factory plug it does not use a sense wire but there is a spot for a sense wire on the alternator labeled S it is is it okay for me to TAP directly onto the metal prong from alternator S to my positive on my battery to keep my voltage so the resting voltage on my lithium will raise a little right now it is averaging 13.8

[@jacquespoirier9071]

@@joshferguson829 if the voltage is steady , leave it alone, 13.8 volts is just OK, you can go higher to 14.4 but at the price of the component life. On industrial applications, 13.8 volts is the target.

[@chandrakanthsudini2954]

Thankyou so much its so helpful

[@OU-xc4os]

Awesome car. Lol i had one and it was a monster doing dounts i6 motor with stick trans. It was a tire melting monster

[@h2omechanic]

I'm trying to wire up a honda 4 wire alt and can't figure it out. Not sure if I can just hook up a old school 2 wire to my racecar

[@khenm5198]

Thank you for this brother..You explain things very good...Now im having an issue getting the Alt to charge batteries on a Generator on a Semi..Now it is hooked up from Alt to starter ,and to Batteries..However my inverter shows me the Alt on the generator is not charging the batteries..Can i leave the other wires in place, and add a wire from my Batteries directly to my Alt to try that??...Thanks..B

[@abcardenas35]

Awesome 👌

[@cartracer64]

thanks for the video. in your diagram you didn't show a fusible link from the alt to the starter solenoid. on your installation you called out a fusible link at the starter solenoid. did you use a 14g fusible link since you are using 10g wire. question: does it matter which end you install the fusible link either at the solenoid or at the alternator and is it mandatory?? thanks

[@coolman6092]

Thaks for sharing

[@GILDIA2803]

great Video, what is the part number for the diode?

[@Hollywood4Fun]

If I want to charge a second battery can I just run off the charging wire of the alternator to the second battery positive? Maybe I could put an off and on switch (household light switch) so it only charges the second battery when I throw the switch? I know you can hook up isolators and all that stuff but I'm just trying to think of the easiest way. I have a little 12 volt refrigerator I'd like to keep active on the second battery and charge it up when I need to.

[@ethandomantay4926]

Your channel was just the thing I needed! I am working on a custom conversion and I could use some help on how I should build my charging system/Ignition system. Is there an email I can contact you at so we can chat? I would greatly appreciate it! I have a 1972 VW Bus with a Toyota 22R bolted to the original VW transaxle! The original bus harness is still being used and I am a beginner to understand electrical. Thanks in advance!

[@TheHortond]

You do yours the same as me. But I run the sensing wire somewhere down the line so it will sense the voltage at the battery so it knows if its charged. Running it off the alternator it only gets the 14 volts its putting out.

[@troyb.4101]

Being that an alternator is on a pully system, and it averages 2.5" while the crank shaft is like 6" the idea of increasing RPM does not seem logical. At 850 idea the alt is like 2000rpm + . I do like this video it is how I would wire one up. Great diagram, explanation is good also. Thanks

[@rayfunk5659]

You nailed the reason for the voltage sensing wire, but running it to the output lug of the alternator is not the right thing to do. Running it back to the battery lug with 10 gauge wire will eliminate all those minute voltage drops in the vehicle wiring and will allow the alternator to charge properly. Another point is the gauge of the output wire. Even a 75A alternator will require more than a 10 gauge wire. 6 gauge would be the minimum and if the run is fairly long an even heavier wire may be required,

[@1RJW381]

THANK YOU✅💯

[@nonyabidness6492]

Weird in your GM wiring you said you should only use the exciter/dummy wire on IGN so that it wont drain your battery? what changed?

[@bradyarebalo9342]

I have an alternator with a red white and a black would color would the exciter wire go to ?

[@drdiabeetus3061]

Awesome! Love it! Need to get some spark plugs in those holes! Don’t need spiders making homes in there.😂

[@chriscraft77022]

i feel sorry for a spider that goes in there.. i put plugs in it today

[@rosemcbirney5123]

Thanks for the reply I’m after the stater wire so I can connect auto choke to it I don’t no which one it is

[@chriscraft77022]

that’s going to drain your battery dead

[@Rosie-ww9yw]

Someone recommended using a 4 gage wire (battery) to run from alternator to starter. Is that too much wire?

[@new_bright_0362]

How much amp is your alternator 75A? also is it OEM?

[@MPDano]

Great video, but is the sensing wire always the top the T terminals as you showed in your video (3:14)?

[@chriscraft77022]

no

[@MPDano]

@@chriscraft77022 is there a way to verify which is which? In a nutshell, sounds like it really doesn't matter as both take 12v's so no real danger in burning up my new alternator, correct? Also, never saw you posting a Part 3 and 4.

[@sixtyfourchebby4507]

Hay how are ya? Hope you're all good! Take care

[@buzzz241]

Thanks for explanation. 😊 However, putting the alternator below a water hose looks 👀 like a very bad idea! 😮

[@chriscraft77022]

that’s factory

[@crabler0015]

3:54 same it's happened with me and I am B.... 😂😂

[@The1978johnny]

I’ll probably would’ve put a solenoid from the starter and used a power junction . That way you don’t have all them amps in the switch and it n the cab.

[@tonyarnold9784]

Great video. I have a 1987 Honda Prelude here in the UK. Red light stays on on dash. Tested battery Voltage when running and not charging. Had alternator tested. Adivised it was faulty so bought new one and still red light on. It has an external VR. Can i run wire direct to positive terminal and test it? Or could it be the exciter issue-which I have never heard of before?

[@chriscraft77022]

is it charging with the red light on? What is charging voltage?

[@tonyarnoldphotography9757]

@@chriscraft77022 No, not charging with red light on. Voltage reading no more or less than 12volts. I am going to checkv over the VRegulator later today in another car which is the same.

[@chriscraft77022]

rev the rpm up and see if it starts charging … an 87 should not have an external regulator

[@natesaunders5628]

Ive got post two looped to the lug just like youve got. But my field wire has power going though it, its not wired to the ignition switch yet. Why does it have power going through it?

[@chriscraft77022]

it shuts power off once the alternator starts charging.. that’s powers your battery light on in the dash

[@christiantabeling1184]

Why do you need the 10 gauge wire from the starter to the Junction block When you got the big red wire going from the Alternator to the battery

[@chriscraft77022]

you can wire it how ever you want .. I dont wire anything to the battery terminals

[@sethwyo7905]

Question how would I wire my voltmeter in here ?

[@pvgreen621]

The altenator shop told me to wire the exciter wire to ghe starter. Can i wire it to the starter lug on my solenoid?

[@chriscraft77022]

You could off S position

[@jerrielynnalvarez893]

I would buy the custom wire set

[@TheMotiMinds]

why does my battery die whenever I try to start it? after I charge it.

[@chriscraft77022]

you have sensing wire and exciter switched if it drains battery

[@doesntmatter3068]

*THANK YOU!!!* I was going nuts trying to find this information out about my alternator! Scare to death I was going to make a CO-BOOM in my garage! My situation a little different. Have a Subaru EA 82 engine on a custom built stand for an airboat. Very few gauges, Bare minimum of a wiring harness, MSD Ignition/Trigger setup. Just didn't know how to wire the dam alternator wired up. (👍 ͡❛ ͜ʖ ͡❛)👍 (I owe YOU a beer)

[@overlandready]

10 gauge wire is 30A you're running that as a main charge wire on a 75A alternator? Can you not see a problem here? Needs to be 4 gauge - 80A for a 75A alternator. anything less can result in FIRE! Not always, but it's a real possibility. You also have to consider inrush current so I'd go with 3 gauge or ideally 16mm² as 110A at 12v. Wire size is massively important! The exciter wirer is also the charge lamp wire, so it should be to a bulb not to the ignition the other side of the bulb goes to ignition 12v source.

[@chriscraft77022]

you are thinking residential wiring. look up automotive wiring charts, in which the run of wire is significantly less and the most important

[@rodfreess6019]

Yes and fire starting tolerance is much less for residential then automotive. Overland can look at anything automotive, the wires are sized much smaller than residential. @@chriscraft77022

[@readytorvdude1224]

If you have 2nd battery banks, can you send a voltage sensor with diode to alternator to tell it to charge 2 battery bank. Even if main battery is fully charged?

[@chriscraft77022]

my snap on truck has 3 separate battery banks and uses a battery isolator to charge all 3 from 1 alternator

[@readytorvdude1224]

@@chriscraft77022 how many amps is the alternator / amp size each bank / length to charge banks as whole or independently.... thanks. A wiring diagram or snap on manual link would be nice also & thanks... I'm looking at purchasing A SNAPON TRUCK ALSO FREIGHTLINER BRAND. YEA... BEEN PREAPPROVED. WAITING FOR LLC FORMATION AND ABOUT TO SCHEDULE PRESALE MAINTENANCE CHECK AND TUNEUP

[@readytorvdude1224]

@@chriscraft77022 do you know the alternator amp output & how much each bank receives during lowest idle & highest idle? The snap-on fl60 im trying to pre-inspect has a idle adjustment knob.

[@chriscraft77022]

@@readytorvdude1224 my snap on truck is 1999 and i have the battery isolator video on my other channel: Chris Craft

[@miloauker8706]

I had a problem with the ignition wire going to the alternator... no volts. I tied the exciter wire to the main alternator stud and seems to be charging fine. Is there any issue running it like that until I get time to trouble shoot the ignition wire?

[@chriscraft77022]

you will drain your battery dead. Voltage sensing has to be hooked up.. not the exciter wire

[@miloauker8706]

Thanks for your reply. I wish my wiring were as simple and clean as your engine bay. I have a 95 Ford L8000 dump truck with a fair amount of harnesses that have been messed with by previous owner. I put a master battery disconnect on the truck so I can isolate the batteries when not in use. I have a Ford 3G alternator. Lost all charging on the job site and replaced the unit. Still was not charging. Jumped from the main stud to the ignition wire and came to life 14.5 volts. Been running it like that for a few days to get the job completed. I was thinking the ignition wire should be hot while running, but mine is not, and will take a bit to go through the harness and take the dash apart.

[@mastermind55615]

I have a 1977 280z but my Black fusible link keeps on getting hot as the revs go higher. Could this method solve that issue, or do you have any other suggestions ? thanks

[@chriscraft77022]

you need to clean all the connections and grounds first

[@chinoizarraras]

2:40 why can’t I jump the voltage wire to the power supply if I have a factory in dash amp meater? I have a 57 Buick

[@chriscraft77022]

you will get a false reading

[@andyuscum]

What would cause the exciter wire to be "hot" when the car is off ? my 65 would not start no click nothing. I was checking all the wires under the hood when i pulled the exciter wire off the alternator it sparked and smoked car still wont start (had to get a tow home)

[@chriscraft77022]

you might have exciter and voltage sensing switched.. that will drain battery

[@andyuscum]

Im pretty sure i installed it back on the same terminal but i will double check that @@chriscraft77022

[@N-e.o]

I used 2 awg-18 wires and used both of them to charge the battery. So basically that's 9-awg right?

[@chriscraft77022]

just make sure they don’t get hot with all your lights on wipers radio everything

[@robbcli5687]

What if you bypass the fuse link on a Chevy electrical wiring system

[@chriscraft77022]

that has been done millions of times... never do it to computers or high amp draw circuits

[@Flyingsgetti]

I'm trying to make a stereo for go-kart we see if this help

[@chriscraft77022]

alternators need sometimes 800rpm and will rob power from the engine so it might not work on a go cart

[@dankjankers6655]

So, I got one of these alternators to replace the original and I didn't know I had to wire it to the starter, mine was still hooked up to the voltage regulator. Now, I think my new alternator is fried..

[@chriscraft77022]

you only fry the battery when voltage sensing isn’t hooked up.. if you hook it up wrong it either drains your battery when car is off or doesn’t charge the battery when running

[@dankjankers6655]

@@chriscraft77022 Turned out that there was a missing plastic piece from the B post that prevented grounding out. That was the cause of the issue. The original wiring that was setup was fine.

[@tomference4618]

...whaoh!..so if I have an aftermarket ammeter, does it wire into that #2 sensor wire?

[@chriscraft77022]

I have an ammeter video.. no, not even close

[@tomference4618]

@@chriscraft77022 please advise,..or put in a link to it. I see lots of Volkswagen stuff, but not specific ammeter. Thank you.

[@randysteinke9802]

What happens if you run 12 v to pin 1 full time

[@chriscraft77022]

It will drain your battery dead when car is off

[@thefernpeople7050]

I wired my Toyota exactly like this. Anyone know why i read 17.5v at the battery when the car is running at about 2000 rpm???

[@chriscraft77022]

your voltage sensing is not wired right. You will catch your car on fire

[@rosemcbirney5123]

Which is the stater wire is it number 1

[@chriscraft77022]

1 is the exciter wire. The (lug) charging wire can go to the starter if it has to

[@samwhite1345]

What if your voltage regulator is built into the alternator

[@chriscraft77022]

that is what the alternator is in the video.. if you have an externally regulated I suggest you throw it away

[@samwhite1345]

@@chriscraft77022 LMAO thank you would you happen to know where I could find rebuild kits for an 86 Nissan I need new staters and brushes ect.

[@chriscraft77022]

if it’s not on rock auto they probably don’t sell them

[@samwhite1345]

@@chriscraft77022 thank you I appreciate it

[@chriscamp5190]

You forgot to mention the ground wire

[@zainrei4917]

Body ground.

[@MechanicForGMCCars]

Men me problems are even wurse 😑😬 those delco 12si are anoying realy expecialy Europ version are shit .I love when the voltage regulator fails or diodes or useing hv capacitors with ignition coil only problem like you described dead baterry or starting charge rpm goes up around 3000-4000rpm smuther engine faster spining starter motor but anoying not abel to run at low rpm shity alternator and curse those 4 pin gm ignition modules . Actualy be me alternator that pin 2 is bend inside the alternator and multipel types of them exist in the market . Peopel often here be use buy tractor alternators if they buy wrong pulley turning ditection they baterry wont charge or that mounted capacitor is dead be tractor alternators they dont charge baterry as well. God knows how much times I asked electritians no one realy culd help me to figure out how to counter back charge or use capacitors on ground to counter plasma ignirion or running capacitor banks with lead acid baterry seperatly. Im just saying men those standard parts are crap I rather chose heavy dutty industry bridge rectifier and use programabel voltage regulator or simply bypass that shity thing. If you know good dual baterry systems please link them so those systems do not interfeare with ich other I dono what to do honestly Im anoyed like hell . Those E Core Hei need terribly more power they do not start realy well on cold winter mornings I advise peopel manual chokes and try some how to trick that deam ignition module to retard ignition timing more to sucessfully start engine or manual retard lever to build for ignition system. For me nothing worked so fare . Not even the 5 pin gm ignition module culd not fix me needs . If any thing I wuld stay away from that crap those alternators are notoriuse for back charge it is cool to run car with out baterry but not if you cant control it. So wuld be nice if some one share some sucess modifing those alternatora .