New Mechman 250 Alternator Question

[Doubeleive]

Howdy. Same deal as zposm1, I bought a MM 250A. The new alt will only be in the vehicle for about three days (it's not my daily) before it goes to the install shop where a big4 along with the system will be installed. I noticed there is a Littlefuse 175 Mega at the battery - would it be a good idea to throw a 250A in there just to be on the safe side for the trip to the install shop? Many thanks!

don't mess with or change that fuse it is designed to protect the vehicle electronics, you go bigger and there is risk of basically ruining modules, bcm, ecm,etc
it's not there for the alternator.
Any audio system amp (should) have it's own dedicated fuse, so that 175 fuse will never have more draw on it than it should.
I have tested my mechman and got the draw up to 220a but that is with everything running full blast and my sub amp on, powered thru it's own fuse. The vehicle draw should not exceed the fuse rating unless there is a short in which case it blows the fuse instead of burning up everything else attached to it.

 

[Heavy]

don't mess with or change that fuse it is designed to protect the vehicle electronics, you go bigger and there is risk of basically ruining modules, bcm, ecm,etc
it's not there for the alternator.
Any audio system amp (should) have it's own dedicated fuse, so that 175 fuse will never have more draw on it than it should.
I have tested my mechman and got the draw up to 220a but that is with everything running full blast and my sub amp on, powered thru it's own fuse. The vehicle draw should not exceed the fuse rating unless there is a short in which case it blows the fuse instead of burning up everything else attached to it.

Understood, I won't touch that fuse. The second AGM under the hood will handle the system and the run to the rear will have it's own dedicated fuse. Thanks again, much appreciated!

 

[xposm1]

The factory 220A alternator off of the newer body style is basically a direct bolt over as well and at a fraction of the cost of the Mechman.

ACDelco Alternator - 13536552​

I bought mine from Amazon back in July for $165.

Looks like the price has gone up along with everything else. It is currently listed at $200

ACDelco Alternator - 13536552 https://a.co/d/i6FcwT9

Now as far as the Big 3 upgrade, do it. It is a total waste of time to upgrade to a high output alternator and NOT upgrade the wiring.

Think of wire like pipes. The bigger the pipe, the more volume of water can flow through it. That volume is equivalent to your Amperage.

Why put an alternator that is capable of producing 200+ amps onto wires that can only carry 70 amps?

@kbuskill Interesting, I didn't know that. Just curious, when you say "basically a direct bolt over"...what did you need to do to get the alternator to fit in your Tahoe? And you installed it on your 2008 Tahoe? Seriously thinking going this route now...

 

[kbuskill]

@kbuskill Interesting, I didn't know that. Just curious, when you say "basically a direct bolt over"...what did you need to do to get the alternator to fit in your Tahoe? And you installed it on your 2008 Tahoe? Seriously thinking going this route now...

I have a 2008 Suburban, but same thing.

@iamdub did kind of a write up on it in his build thread. It plugs in and bolts up, the bolt holes on the back side are ever so slightly larger than the holes toward the front and you can put a sleeve in them to take up the slack. But in all honesty, I was kind of in a rush to get mine put on since the truck was down and my sleeves had not arrived yet so I just bolted mine on and haven't had any issues with it as is. The sleeves arrived later and I will probably eventually put them in but I'm in no real rush.

Here is a couple pics...

You can see there is an extra "Ear" in this pic, Dub shaved this off of his but it is not in the way of anything and again, I was in a hurry to get the Burb back up and running since the original one took a crop.

And another pic...

I realize this doesn't really show much as far as the mounting and such but as you can see it just fits.


In this pic you can see there is also a 90° adapter on the back which bolts to the output lug/terminal of the alternator. The bolt would be sticking straight up in the pic with the cable coming off and going to the left/passenger side in this picture. DUB took his off, I left mine on and it doesn't interfere with anything and I have marine grade 2/0 cables I built for mine just for reference.

 

[iamdub]

@kbuskill Interesting, I didn't know that. Just curious, when you say "basically a direct bolt over"...what did you need to do to get the alternator to fit in your Tahoe? And you installed it on your 2008 Tahoe? Seriously thinking going this route now...

As Ken said, it's a direct replacement. I can't leave anything alone and saw room for improvement in fitment, performance and appearance. So THIS is what happened. I destroyed that 90° main lug tower during experimenting so my charge cable makes an odd (IMO) loop. Meh- it's under the cover so it's not visible. Even though the rears of the bolt holes are 4 mm wider, it'll bolt in and be fine as-is. I had stuff to make the rears 10mm holes like the fronts and it only took a few minutes longer to do. I just used some spacer sleeves from an old set of Moog sway bar end links, like the ones standing vertical in this pic:

 

[xposm1]

I have a 2008 Suburban, but same thing.

@iamdub did kind of a write up on it in his build thread. It plugs in and bolts up, the bolt holes on the back side are ever so slightly larger than the holes toward the front and you can put a sleeve in them to take up the slack. But in all honesty, I was kind of in a rush to get mine put on since the truck was down and my sleeves had not arrived yet so I just bolted mine on and haven't had any issues with it as is. The sleeves arrived later and I will probably eventually put them in but I'm in no real rush.

Here is a couple pics...
View attachment 408694
You can see there is an extra "Ear" in this pic, Dub shaved this off of his but it is not in the way of anything and again, I was in a hurry to get the Burb back up and running since the original one took a crop.

And another pic...
View attachment 408695
I realize this doesn't really show much as far as the mounting and such but as you can see it just fits.

View attachment 408696
In this pic you can see there is also a 90° adapter on the back which bolts to the output lug/terminal of the alternator. The bolt would be sticking straight up in the pic with the cable coming off and going to the left/passenger side in this picture. DUB took his off, I left mine on and it doesn't interfere with anything and I have marine grade 2/0 cables I built for mine just for reference.

Awesome! Very helpful Thanks!

 

[xposm1]

As Ken said, it's a direct replacement. I can't leave anything alone and saw room for improvement in fitment, performance and appearance. So THIS is what happened. I destroyed that 90° main lug tower during experimenting so my charge cable makes an odd (IMO) loop. Meh- it's under the cover so it's not visible. Even though the rears of the bolt holes are 4 mm wider, it'll bolt in and be fine as-is. I had stuff to make the rears 10mm holes like the fronts and it only took a few minutes longer to do. I just used some spacer sleeves from an old set of Moog sway bar end links, like the ones standing vertical in this pic:

View attachment 408712

Thanks!

 

[2006Tahoe2WD]

Not sure if the design of the 2010 is similar to my 2006. The alternator is somehow connected to the "computer" as part of controlling the output. The voltage is high for awhile and then drops as the computer "thinks" the battery is charged after doing some starting work.

 

[Doubeleive]

Not sure if the design of the 2010 is similar to my 2006. The alternator is somehow connected to the "computer" as part of controlling the output. The voltage is high for awhile and then drops as the computer "thinks" the battery is charged after doing some starting work.

they work the same 05-20

 

[adriver]

Apologize if this isn't in the correct spot.

I have a 2010 Chevy Tahoe LT w/ towing package. The stock alternator is on it's way out (Stock is 160A KW1). I am looking at the Mechman 250 Amp alternator (Model #8302250). If I go with this alternator, do I have to do the big 3 upgrade? or is truly a drop in with no upgrades/changes needed? also looking if anyone has used this model and what their experience has been.

Link to Alternator:
Mechman 250A Alternator



Thanks

If you're upgrading to a mechman 250 because you are going to have a larger draw, (from probably a stereo), then cool, but you only have a few posts, and it's common for people to be concerned about the dropping voltage. 05+ the alternator's voltage is no longer internally regulated, and instead the voltage is controlled by the ECU in order to reduce drag and increase mpg. Voltage dropping down to as low as 11 volts while running is doing what it's designed to.

if you plan on having an additional draw of 90 amps, that should cover somewhere around 1300w-1500w. You might also want to look into changing that voltage so that it's a steady 14.* volts.

90 amps x voltage, lets say 14.4 = 1296w.
1296w x amp efficiency (call it 80%)= 1036w about a 1000w from amp.
That's when your sub is hitting on full at full volume. You have some room in your stock, and that 1000w is not a full draw all the time, (it's charging between those hits). Depending on the music, you can usually go 30-50% over that and still keep fully charged at full volume.