High Output Alternator and Big 3 Question (Answered)

[gmartin1215]

Hi,

I decided to upgrade my 160 A alternator to the Mechman 250 A. Reasons I decided to upgrade are because I am running a winch, LED lights, dual 700 w e-fans, and plan to add other electrical accessories.

I tried asking Mechman questions about what is needed for installing their alternator to handle and utilize the higher output amps. Tony Bolton is the person I chatted with and he said everything for the model I selected (8302250) is plug and play with the addition of running a 0-gauge wire from the alternator directly back to the battery positive post. I asked if I should remove the OEM alternator wire that goes back to the mega fuse, but Tony said to leave all the OEM wiring alone, and reiterated that all I need to do is just add this 0-gauge wire from their alt to the battery, and leave everything else alone. To me, this does not make sense to have a unfused wire and the fused OEM (through the mega fuse) one going back to the battery , but I'll admit that I am lacking knowledge here, but I want to learn, too. I asked Tony this question, but he kept reiterating to leave everything else alone without giving an explanation.

I then mentioned that I am interested in doing the Big 3 and asked if I still need to have the additional 0-gauge from the alt to the batt. Tony got on a soap box and said that it is not 1985 anymore and the truck I have is not a unibody or glued together one, or basically saying Big 3 is not needed without directly saying that. He again said to leave everything alone and reiterated just adding the 0-gauge wire from the alt to the batt positive. Then went on to say that I would do better by spending wire money on their voltage controller (MM-VCI) or one their alternators with RVC bypass. I mentioned that there are many who are doing the Big 3 on these vehicles, so I asked Tony to explain what he means. Here is what he said:

"You can choose who you want to believe, its just marketing and ways to sell cable. Been that way for years. The only ground on your whole vehicle is the negative battery post. The alternator makes the power; the battery stores the power. Getting the power to the battery is the first step, then battery to the component(s) that are added to the vehicle. Start adding a bunch useless grounds and you only set yourself up for a ground loop noise situation.

Using the MM-VC1, the “loop” is irrelevant. MM-VC1 over any “wire upgrade” is a no brainer. Volts go up/stay up, amperage draw goes down.

You can buy all the cool internet wiring and connectors you want, it doesn’t change the fact you’re not fixing some crap wiring on a 40 year old vehicle. Those things came with like 40-60 amp alternators. Your truck has/had at least a 140 amp and the wiring has improved over the years.

Quality, not quantity."

I tried asking more questions to Tony, but he was clearly getting frustrated with me and gave me links to their instructions and said to go read those for explanations or go to a shop if I am feeling intimidated about it. I am giving up asking this guy more questions. I wanted explanations because I want to learn, and I was not feeling intimidated by it. Good luck to anyone asking questions at Mechman and especially if you get Tony.

This has just been one guy's opinion, and he may be right. However, I would like to get more opinions from this group.

Does Tony's suggestions and comments make sense?
What about his comments on the Big 3 and just get their voltage regulator? Almost seems like all this was just some pitch to get me to buy their device.
Would you leave this additional 0-gauge to the battery from the alt unfused? To me, that feels unsafe if something catastrophic happens.
Where is a good source to get wiring? I know I should get OFC?

Right now, I am unsure if I just do his suggestion of leaving all the OEM wiring alone and just add this 0-gauge, or go back and read how others have installed their high output alts and go that direction.

Anyway, I hope you all can help on this topic.

 

[mikez71]

Alt wire on top is about as likely to short as your battery cable, which has no fuse to starter.
The stock secondary battery cable also has no fuse.
If you route it well, I wouldn't worry.

Adding a fuse is nice since you can carry a spare main fuse..
(I used a small fusebox for my second battery, but you could use a single fuse holder)

 

[CMoore711]

I don't have much to contribute because I'm also learning; But I'm starting to experience what I think is some ground wire feedback "whining" noise through my speakers that increases with acceleration. It's also not there all the time, as in sometimes doesn't exist and is radio silent. So I've been going down the same upgraded alternator plus big 3 rabbit hole as I think you have been as well @gmartin1215 .

I've also been checking out JS Alternators (recommended by my local car audio guru w/ many years experience): https://js-alternators.com/?gad_sou...seF-B8DZ-paXUJ_VQo6bZpNxm64gCMyUaAjKlEALw_wcB

2007-2022 Cadillac Escalade ESV V8 6.2L High Output Alternator

Upgrade your 2007-2022 Cadillac Escalade ESV 6.2L 250-320-370-400amp High Output Alternator | JS Alternators with a JS high-output alternator. Ensure reliable power for all electronic components, even under heavy load. Durable & performance-tested. Shop now!

js-alternators.com

They offer Big 3 wiring kits as optional add-ons to their alternators and state they are "Required for all H.O. Alternators". I haven't gone as far as to reach out to them for a conversation. But I would be very interested to hear their responses and answers to the same questions you attempted to get answered by Mechman!

 

[Joseph Garcia]

Hi,

I decided to upgrade my 160 A alternator to the Mechman 250 A. Reasons I decided to upgrade are because I am running a winch, LED lights, dual 700 w e-fans, and plan to add other electrical accessories.

I tried asking Mechman questions about what is needed for installing their alternator to handle and utilize the higher output amps. Tony Bolton is the person I chatted with and he said everything for the model I selected (8302250) is plug and play with the addition of running a 0-gauge wire from the alternator directly back to the battery positive post. I asked if I should remove the OEM alternator wire that goes back to the mega fuse, but Tony said to leave all the OEM wiring alone, and reiterated that all I need to do is just add this 0-gauge wire from their alt to the battery, and leave everything else alone. To me, this does not make sense to have a unfused wire and the fused OEM (through the mega fuse) one going back to the battery , but I'll admit that I am lacking knowledge here, but I want to learn, too. I asked Tony this question, but he kept reiterating to leave everything else alone without giving an explanation.

I then mentioned that I am interested in doing the Big 3 and asked if I still need to have the additional 0-gauge from the alt to the batt. Tony got on a soap box and said that it is not 1985 anymore and the truck I have is not a unibody or glued together one, or basically saying Big 3 is not needed without directly saying that. He again said to leave everything alone and reiterated just adding the 0-gauge wire from the alt to the batt positive. Then went on to say that I would do better by spending wire money on their voltage controller (MM-VCI) or one their alternators with RVC bypass. I mentioned that there are many who are doing the Big 3 on these vehicles, so I asked Tony to explain what he means. Here is what he said:

"You can choose who you want to believe, its just marketing and ways to sell cable. Been that way for years. The only ground on your whole vehicle is the negative battery post. The alternator makes the power; the battery stores the power. Getting the power to the battery is the first step, then battery to the component(s) that are added to the vehicle. Start adding a bunch useless grounds and you only set yourself up for a ground loop noise situation.

Using the MM-VC1, the “loop” is irrelevant. MM-VC1 over any “wire upgrade” is a no brainer. Volts go up/stay up, amperage draw goes down.

You can buy all the cool internet wiring and connectors you want, it doesn’t change the fact you’re not fixing some crap wiring on a 40 year old vehicle. Those things came with like 40-60 amp alternators. Your truck has/had at least a 140 amp and the wiring has improved over the years.

Quality, not quantity."

I tried asking more questions to Tony, but he was clearly getting frustrated with me and gave me links to their instructions and said to go read those for explanations or go to a shop if I am feeling intimidated about it. I am giving up asking this guy more questions. I wanted explanations because I want to learn, and I was not feeling intimidated by it. Good luck to anyone asking questions at Mechman and especially if you get Tony.

This has just been one guy's opinion, and he may be right. However, I would like to get more opinions from this group.

Does Tony's suggestions and comments make sense?
What about his comments on the Big 3 and just get their voltage regulator? Almost seems like all this was just some pitch to get me to buy their device.
Would you leave this additional 0-gauge to the battery from the alt unfused? To me, that feels unsafe if something catastrophic happens.
Where is a good source to get wiring? I know I should get OFC?

Right now, I am unsure if I just do his suggestion of leaving all the OEM wiring alone and just add this 0-gauge, or go back and read how others have installed their high output alts and go that direction.

Anyway, I hope you all can help on this topic.

Personally, I think that you've got all that you need for data/opinions, and it is time for you to make your own decision. Any more data/opinions at this time is not going to be helpful to you in making that decision.

Personally, I don't think that you can go wrong, either way.

Recommended Length and Amperage for Battery Cable while maintaining a 2% or less voltage drop at 12 volts
Battery Cable Size	50 Amps	100 Amps	150 Amps	200 Amps	300 Amps
6 Gauge (AWG)	11.8 ft	5.9 ft	4.4 ft	2.9 ft	2.2 ft
4 Gauge (AWG)	18.8 ft	9.4 ft	6.3 ft	4.7 ft	3.1 ft
2 Gauge (AWG)	29.8 ft	14.9 ft	9.9 ft	7.4 ft	4.9 ft
1 Gauge (AWG)	37.7 ft	18.9 ft	12.6 ft	9.4 ft	6.3 ft
1/0 Gauge (AWG)	47.5 ft	23.8 ft	15.9 ft	11.9 ft	7.9 ft
2/0 Gauge (AWG)	60 ft	30 ft	20 ft	15 ft	10 ft
3/0 Gauge (AWG)	75.6 ft	37.8 ft	25.2 ft	18.9 ft	12.6 ft
4/0 Gauge (AWG)	95.2 ft	47.6 ft	31.7 ft	23.8 ft	15.8 ft.

 

[gmartin1215]

Personally, I think that you've got all that you need for data/opinions, and it is time for you to make your own decision. Any more data/opinions at this time is not going to be helpful to you in making that decision.

Personally, I don't think that you can go wrong, either way.

​

Recommended Length and Amperage for Battery Cable while maintaining a 2% or less voltage drop at 12 volts
Battery Cable Size	50 Amps	100 Amps	150 Amps	200 Amps	300 Amps
6 Gauge (AWG)	11.8 ft	5.9 ft	4.4 ft	2.9 ft	2.2 ft
4 Gauge (AWG)	18.8 ft	9.4 ft	6.3 ft	4.7 ft	3.1 ft
2 Gauge (AWG)	29.8 ft	14.9 ft	9.9 ft	7.4 ft	4.9 ft
1 Gauge (AWG)	37.7 ft	18.9 ft	12.6 ft	9.4 ft	6.3 ft
1/0 Gauge (AWG)	47.5 ft	23.8 ft	15.9 ft	11.9 ft	7.9 ft
2/0 Gauge (AWG)	60 ft	30 ft	20 ft	15 ft	10 ft
3/0 Gauge (AWG)	75.6 ft	37.8 ft	25.2 ft	18.9 ft	12.6 ft
4/0 Gauge (AWG)	95.2 ft	47.6 ft	31.7 ft	23.8 ft	15.8 ft.

When I have uncertainties where there have been mixed opinions, then I am going to keep asking questions. Right now, I don't have a clear direction which way to make a decision. Do the Big 3. Don't do the big 3. Fuse. Don't fuse. Run a big wire to the batt from the alt and leave everything else alone. No! Don't do that! Run the same size wire for your ground, too. And so on. With all these different opinions its hard to make a clear decision. Looking at other manufacturers install instructions also contradict each other. The guy at Mechman said things that contradicted their instructions.

So yeah, I don't have enough data yet to make a decision when I still have uncertainties.

 

[mikez71]

If you haven't run into an issue yet, it's all just icing on the cake.
You can always upgrade wiring later.

Some like overkill, some want it simple, some just copy others.
Differing is not necessarily contradictory, all good reasons/choices.

Then you gotta pick a color.. (well.. maybe not for alternator cables, but it's very difficult when painting a room)

 

[j91z28d1]

can you link to this big 3 you're wanting to buy?


my 2 cents is the same as before. following what the oem did on the 220amp alt trucks. buy a oem 220amp and do what they did with wiring size from alt to battery and their size fuse and then forget about it.


as for the mechman. have you googled reviews? I've seen a few things over the years about them blaming install and wiring for alt failures. while they could be 100% right about it, or wrong I don't know. on the corvette side guys love buying high priced fancy things they don't need for their cars sitting in garages. so it's pretty common buy, i didn't, I used a oem 220amp and happy I did.

if you don't wire it just as they say, they might give you issues if or when it fails. nothing lasts forever.

 

[Joseph Garcia]

When I have uncertainties where there have been mixed opinions, then I am going to keep asking questions. Right now, I don't have a clear direction which way to make a decision. Do the Big 3. Don't do the big 3. Fuse. Don't fuse. Run a big wire to the batt from the alt and leave everything else alone. No! Don't do that! Run the same size wire for your ground, too. And so on. With all these different opinions its hard to make a clear decision. Looking at other manufacturers install instructions also contradict each other. The guy at Mechman said things that contradicted their instructions.

So yeah, I don't have enough data yet to make a decision when I still have uncertainties.

OK. You keep on digging down this rat hole, and let's see where you come out. Maybe another 20-30 opinions or Google search articles will eliminate all of your uncertainties, and allow you to finally make a decision.

It is your decision to make for sure, but I'm going to state right now that you will always have uncertainties in this area, just because that's the way that the world works.

If/when you have finally eliminated all of your uncertainties, please edit your thread title to include the words, "All Uncertainties Eliminated", and then I'll take a look at this thread again, and see what you found/decided.

I do wish you the best of outcomes on your project.

 

[j91z28d1]

OK. I looked up the fuse size.. a 2015 3500 6.0 with 220amp 22949466 alternator had a 250amp mega fuse in the B+ from alt to fusebox terminal/battery pos.

check how long your wire is on your truck. use the chart posted above for the wire size, I'd say use the 300amp colnum, since it's better for the fuse to blow long before the wire gets warm.

if you're about 3ft long, a 4 GA wire would be fine. error on the bigger side. replace your factory, I'm guessing 8ga wire with 4, replace your smaller fuse for 250amp and you should be good to go.

if you did the 250amp alt, same thing but use a 275amp fuse.

 

[mikez71]

my 2 cents is the same as before. following what the oem did on the 220amp alt trucks. buy a oem 220amp and do what they did with wiring size from alt to battery and their size fuse and then forget about it.

^This^

When in doubt, K.I.S.S.

I agree with Joseph. it sounds like you want an electrical engineer to tell you the theroretical absolute best setup.
Never heard of any problems..
EXCEPT the thread where a guy had all kinds of diagrams and wiring, but installed the battery backwards..

You really only have two options, replace original cable, or add additional cable.
(bigger ground might be good too, the one place I might disagree with Tony, but you can add that anytime)

 

[Doubeleive]

I don't really have anything else to add except I did not "add" a wire from the alternator to battery I just increased the wire size from the alternator to the existing connection at the fuse, replacing the oem charging wire which on the 2012 is right there at the battery and not on the firewall like the older models.

While ultimately Tony may be correct on the battery ground, a ground will always take the shortest path otherwise you would never get a single burnt wire anywhere else except at the battery so poor grounds do exist, if your instrument cluster is flickering, interior lights flickering or your headlights are flickering replacing the battery ground cable alone is not always the one culprit. (tell me I'm wrong?)

that mm-vc1 seems kind of neat, I would like to see what long term effect it may have on battery state of charge, that being said my system seems to be working fine without it, I did add a 0 gauge ground from the alternator mounting bracket to the frame on the drivers side. I decided not the mess with the RVC setup.
I only have a basic car audio amp and subs added on the Yukon.

On the silverado I do have a winch added on and 2 car audio amps, it is running the oem alternator and oem wiring and it also works just fine. the only grounds added is grounds for the amps on the body and the same for the winch, the power wires for each are connected to the battery.

 

[gmartin1215]

I don't really have anything else to add except I did not "add" a wire from the alternator to battery I just increased the wire size from the alternator to the existing connection at the fuse, replacing the oem charging wire which on the 2012 is right there at the battery and not on the firewall like the older models.

While ultimately Tony may be correct on the battery ground, a ground will always take the shortest path otherwise you would never get a single burnt wire anywhere else except at the battery so poor grounds do exist, if your instrument cluster is flickering, interior lights flickering or your headlights are flickering replacing the battery ground cable alone is not always the one culprit. (tell me I'm wrong?)

that mm-vc1 seems kind of neat, I would like to see what long term effect it may have on battery state of charge, that being said my system seems to be working fine without it, I did add a 0 gauge ground from the alternator mounting bracket to the frame on the drivers side. I decided not the mess with the RVC setup.
I only have a basic car audio amp and subs added on the Yukon.

On the silverado I do have a winch added on and 2 car audio amps, it is running the oem alternator and oem wiring and it also works just fine. the only grounds added is grounds for the amps on the body and the same for the winch, the power wires for each are connected to the battery.

Thanks. Did you increase the size of the wire from the battery neg through the RVC, too, that goes to the engine block, or left that OEM? I think you said you increase it another post, at one time.

 

[gmartin1215]

OK. I looked up the fuse size.. a 2015 3500 6.0 with 220amp 22949466 alternator had a 250amp mega fuse in the B+ from alt to fusebox terminal/battery pos.

check how long your wire is on your truck. use the chart posted above for the wire size, I'd say use the 300amp colnum, since it's better for the fuse to blow long before the wire gets warm.

if you're about 3ft long, a 4 GA wire would be fine. error on the bigger side. replace your factory, I'm guessing 8ga wire with 4, replace your smaller fuse for 250amp and you should be good to go.

if you did the 250amp alt, same thing but use a 275amp fuse.

Thanks for looking into what those models have. Good tips!

I was almost considering to get that alternator, but MM gave me a discount and that cost brought it down to about the same as a new 22949466, so went for that since they touted it has better components than the OEM alts, and others on this forum seem to like them.

I guess part of me is still concerned that if I swap the 175 A megafuse to something higher, will I be at risk of frying something else out.

 

[mikez71]

Just make sure your cable has higher capacity than the fuse.

If you're still concerned.. you'll have to find SOMEONE you TRUST.

Same thing I told my mom when she went crazy..
(what other choice do you have?)

 

[Doubeleive]

Thanks. Did you increase the size of the wire from the battery neg through the RVC, too, that goes to the engine block, or left that OEM? I think you said you increase it another post, at one time.

NO, it's oem I did replace it at one point with a new one because I thought maybe the sensor took a dump but after a lot of testing in the end it was a bad battery

 

[kbuskill]

Here is another thing for you to worry about and stress over.

High output alternators don't charge well at idle unless you spin them faster by using a smaller pulley.

Just thought I would throw that into the mix for you to get a hundred more opinions on.... lol

 

[gmartin1215]

Here is my current thought for this 250a install:
- Run a larger wire (1/0) from the alt back to the connection at the mega fuse; remove the oem wire (according to that chart, this is bigger than I would need on the wire size, but MM recommends this size so I'll lean this way)
- Run a larger wire (1/0) from the mega fuse back to the battery positive; remove the oem wire
- Run a larger wire (1/0) from the battery negative through the RVC and to the post on the engine block; remove the oem wire
- Run the smaller oem wire from the battery negative through the RVC to the frame connection that is near the radiator (existing connection)
- Upgrade the 175 A OEM mega fuse to 275 A or 300 A.

The last point I am not entirely sure of how much risk this may cause to the rest of the system. But if I am running a 250 A alternator, then to me it makes sense that I should be running a fuse that can handle this output. I know @j91z28d1 mentioned the 2015 trucks with a 6.0L OEM 220 A alternator are using at 250 A megafuse, but I am not sure how much different critical components like the BCM are from my 2009 with a 5.3L and if they are designed to handle more power.

Anyway, do you think my approach is on the right path? Is there anything you would change?

I am not comfortable with Tony at MM suggestion of leaving all the OEM wiring in place and just add the 1/0 wire from the alt to the B+. I think this will be redundant and will bypass the the protection from the mega fuse. He may be right though since he is in the business and have seen way more of these installs than me. But it just seems odd that is the only thing I should do. If you think his suggestion is viable, then please let me know. It would save some money on wiring.

The MM alt has the standard pulley. And no, I am not going down the pulley size rabbit hole.

 

[mikez71]

Don't worry, your BCM won't know anything..

Honestly, I don't even know what you're talking about...

Your cable replacement sounds dandy.

Does the factory small frame ground also run through the rvc sensor? I never noticed it..

 

[j91z28d1]

the mega fuse really only protects the wire from the alt to the battery side of the fuse. incase it grounds out and dead shorts. or if the alternator internal shorts or something. if say from the battery postive terminal to basically any ground point anywheres touches, the battery can discharge way more than 300 amps and that fuse won't below. there's no protection provided by that meg fuse to anything else in the car. that's what the fuse block full of small 5 to 30amp fuses are for.

things like modules don't use more power because the source can supply more amps. you'd have to increase voltage to force more energy into something to damage it. like say putting a 24v alt on a 12v system would fry stuff, but never blow a fuse because it's voltage, not current. fuses are basically there to pop if there's a dead short and protect the wiring between the fuse and the short from catching fire.

to be honest, if you out a amp clamp meter on that B+ wire off the alt, with the truck running and read the current and then change the alt out and test again. unless your current alt can't keep up with the load you have on it now, you won't seen any difference in amp load on the meter. alt will only supply what is needed.

 

[gmartin1215]

Don't worry, your BCM won't know anything..

Honestly, I don't even know what you're talking about...

Your cable replacement sounds dandy.

Does the factory small frame ground also run through the rvc sensor? I never noticed it..

it does on mine