How to diagnose an Alternator, and properly install a One Wire alternator with more Amps. 

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The thing to do with 1 wire alternator is to send it back to the manufacturer. Use a 3 wire alternator. The exciter wire starts the charging. The sense wire actually senses the load at the load center and compensates for voltage drop. While putting the battery in the trunk is "cool", it creates voltage drop due to the length of wire. Never use painless wiring.

Hi Monty, I thought battery terminals or battery :). You mentioned an excuse for a new gauge - battery (voltage) I agree. Glade to see you fixed the problem. The wiring looks GREAT! Hats off to the Optima battery too.

Thank you so much Monty for this video!! I’m going through the same thing. I have a 1934 ford 3 window coupe that has the same March serpentine kit, with a March Crome alternator with a billet wheel that is about 10 years old. Changed the battery and it still wasn’t charging properly. The alternator spins freely, also shows on the voltage gauge that it was charging but at 10 volts. I checked the ground and it seems good. Thank you for the information about Tuff stuff making March alternators. I was struggling trying to find a good replacement.

Hi Mike. I asked PowerMaster why my new alternator stopped so quickly (like yours does) when spinning by hand. They said it was normal because the new parts and brushes have to wear in together.

Glad it wasn’t a bigger issue thx for the learning 😊

Bad alternator, at least it was an easy fix, no hunting for strange things. Hey, why not rebuild your old unit with a diode block and new regulator, which has new brushes, and put it on the shelf as a good spare?

Great video Monty! You really should do the big 3/big 4 wiring upgrade. I’m rewiring my TA now and I’m using 2/0 wire from the starter to the fuse/battery in the trunk, plus a full run of 2/0 for the ground from the block to the battery in the trunk. I’m also adding an extra 2/0 ground off the block to the frame, the alternator bracket to the frame, and another 2/0 ground from the battery to the frame. Also use 100% oxygen free wire and copper lugs. I have a large audio system in my daily driver (340amp alt, large Northstar AGM main battery, cyber 12k lithium battery, and large amplifiers) It is wired nearly the same and my voltage is rock steady.

Haven't seen you post in awhile. Always good to see a new post from you pop up Mike. My guess is brush failure in old Alt. Good to see you've got the GTO rolling in time for the next event.

Awesome video but I think the only thing I would’ve done different was I would’ve changed the belt rather than changing that pulley. I always say that because the bigger pulley might change the voltage coming out because it’s bigger on the old one that it is on the new one the new one with the smaller pulley is going to spin faster, therefore throwing more voltage, I think

Ha! I knew you would find it 😊 I have been trying to track down the cause of my fusible link burning out in my 1990 Dodge Dakota, I did an alternator swap a few months ago when I got the I'm going to check that out it's one of the things I haven't checked yet been 3 months and I can't find the cause of the short😢

Awesome video. I have a bad alternator on 65 c10. On other videos they suggest checking alternator fuse 1st but I can't find one. I have old 12v fuse box. Any suggestions would be appreciated. Great channel

Glad it was an easy fix Mike. I see your windshield wiper motor is modern, what is it out of?

From my understanding from “generators” you get a residual electric charge from any type of rotation. Since is AC voltage getting turned into DC voltage after your one way diode. So if it free spins it can be an indicator of it not having a strong enough magnetic field. Same reason why you should free tow teslas the wheels still spinning can cause a drag

Great educational video!!

Good information! Do you have a video of the relocation of your battery to the trunk?

thanks for the video and installation went well. the old alternator spun easier due to old bearings versus new?

as always great video . . Question when you ran the dual fans, did you upgrade the ATL then ? (I may have missed it if you said it)

Nice Job !!!

Beautiful car I have a question would you recommend this one wire set up over 3 wire configuration. I have a 69 Chevelle I upgraded my alternator to a 120 amp now i need to upgrade the wiring. It's easiest to go the one wire route because i would have to run a6 gauge or 4 guard wire to the horn relay and another big wire back to the battery from the horn relay.

Off topic question. Helped a friend install a new wiring harness kit in his 1986 C10. Starts fine, idles fine, charges fine, but when shut off and not used. Alt heats up really hot, even when left over night. Ideas?

you installed a 160a alternator with a 200a fuse. the fuse should be the weakest point in system and below the 160a ?

How do you check the external regulator device

Hey Monty, did you have a weak start sometimes? I think I have a weak alternator I’m having a weak start and idle. dimming lights and when I give it gas it goes from 12.3 around about to 13.8 around about ive been having low voltage problems for a bit guessing that’s it. Got a multi meter but it doesn’t even turn on haha have to go return it for sure

Hmm, Perhaps the brushes, a simple task to verify might resolve this , before buying anther ALT? There things are very straight forward and likely take standard diodes, bridges, brushes, springs bearings etc. I got a lot of my GM ALT pieces for them from McCombs elec supply

i have a March system. I need the same alternator. Is there a chance you could give me the model number.

It's easy to be a critic on this side of the computer screen, but if the engine starts to stumble and electrical components start to act weird while the engine is RUNNING, it's almost NEVER going to be the Battery. The battery is an electrical storage compartment and electrical buffer for the electrical system. When everything is connected properly, the alternator has a built-in regulator to maintain voltage, and it modulates necessary amperage based on electrical load. In other words, if the alternator fails (even during mid-trip), the available battery voltage (& capacity) will gradually diminish, causing drivability issues as components are starved for voltage..... okay: ELECTRICITY for the novice out there. This condition is immediately validated by the slow cranking speed during the attempted engine re-start: The battery has lost it's capacity. (Ok, Ok.... I'll give you props for the "Hot-Soak" condition - -- yes, this happens as well.) But sorry: The sequence of events and field-observations would immediately steer a seasoned technician towards the alternator, not the battery. . Another technical error I'd like to point out: You are absolutely correct about never disconnecting the negative battery terminal while the engine is running. Yes, it can destroy electrical components on modern vehicles, but it's not due to amperage issues. It's due to voltage spikes. First, a voltage spike will happen as the neg wire is disconnected...the alternator is all of a sudden confused as to voltage regulation; it'll immediately max out and/or go haywire due to the absence of battery buffer in the circuit. Additionally, if this {terminal disconnect test} doesn't kill the electrical components, reconnection can due to another voltage spike event...as evident by the sparking terminals. Reading up on switch "bounce" validates this paragraph. . Furthermore, recall the famous formulas "Volts x Amps = Watts" and Ohm's Law (V = I * R ). ...and here is the WATERED-DOWN explanation for this one: An electrical gismo is generally rated by power (watts) at a certain anticipated running voltage, but its internal resistance generally remains constant. A functional alternator, spinning with Neg battery terminal disconnected, will generally "Max-Out" on voltage and provide maximum amperage on demand. Going back to the formulas, they can be combined algebraically, resulting in {Voltage (squared)} / Resistance = Watts. If the gizmo resistance remains the same, and the voltage increases, then wattage increases by V (squared). Basically the gizmo burns up because it can't handle the power output. Solid State devices "burn up" due to overvoltage as well, but such properties can be vastly different and is a story for another book. ....basically damage is done at junctions. Oh... I'm not going down that rabbit hole. . As for the new alternator spinning more "sticky"... too many variable to consider. Different bearings, different tolerances, different design. But generally speaking, things "loosen up" as they're broken in. . ....if you made it this far in reading, I've been a tech for 40+ years. I know a lot of stuff.