Mechman 250A alternator

[shizzzon 461]

There is a review coming up soon for this so stay tuned.

Ordered thursday, it was built, tested, shipped and received in only 3 business days from TN to KY.

It will try to be installed by the end of the week or early next week.

Pics and performance readings to come soon.

This alt is definitely nice.

Weighing in at what it looks like 16-17 lbs. I'll get a better reading next time.

Rated to do 250A full tilt.

[johnecon2001 82]

Full tilt meaning what? What about idle output?

[shizzzon 461]

You want to know what it does or what they say?

They say it does around 150A at idle but i could have swore that it was rated to do around 112A at idle.

Disregard the numbers though, i'll find out for sure when i clamp it after installation.

Oh, and full tilt meaning it's maximum output which should be 1700-2000 RPM engine.

[mazzasec 0]

I heard the 250 does around 150 at idle as well.

[jonbearsmt 919]

is it RPM of the motor... or RPM of the alt... i have heard thay rate based on RPM of the alt... not the motor.

[mazzasec 0]

I was talking to Mechman. I didnt know what would have been better for my application a 300amp or 250amp. He said that the 300amp does about 80 at idle. So unless you dont mind reving the engine to 2000rpm he said that would be the best bet. As for the 250 amp does 150 at idle. So the 250 is better if you just wanna beat it and not have to worry about keeping your RPM's high at all time to get the maximum output of the alt.

Edited August 22, 2008 by SEC

[shizzzon 461]

UPDATE-

Got the car in the shop and will be picking it back up tomorrow.

In the meantime, i looked at the box that it came in and realized that a lot of paperwork came with the alternator that i looked over.

So, when purchasing an alternator from MechMan, here is what to expect-

It comes with your invoice stating their location, phone number, fax number and a copy of your order and invoice number.

The next paper-

This is a MUST for anyone. When you buy an alternator from Mechman, they give you a rundown of all the Do's and Don'ts on how to operate your alternator. It is VERY informative and if followed will keep your alt and car in top running performance.

The next paper-

Test results-

This paper shows the tests that the alternator went through with results to show you exactly what your alternator is capable of doing in your vehicle.

Below is 2 RPM readings that you wil see that each test was taken. The test paper shows the actual alternator rpm but to prevent you from doin the math, i already did it for you so u can just read this and drool, hehe.

All of the following rpm numbers have been converted for Engine speed. There are 2 engine speed rpms given. The 1st engine speed is using a 3:1 pulley ratio. The 2nd is using a 3.5:1 pully ratio. If you do not know what yours is, just go by the 3:1 as that is pretty standard for a large array of vehicles.

533\457 - 36.2A

600\514 - 69.0A

667\571 - 100.7A

833\714 - 154.4A

1000\857- 185.9A

1333\1143-219.2A

1667\1429-240.8A

2000\1714-254.0A

2333\2000-257.9A

2667\2286-256.6A

Alternator rated at 250A

Maximum Current - 257.9A

Maximum Watts - 3,159w

Turn on Speed - 272 RPM

Zero Output Speed - 431 RPM

Voltage Set Point - 14.957v

Voltage Set Point at Double Load - 14.869v

Voltage Set Point at Maximum Speed - 15.012v

Voltage Set Point After Load Test - 14.737v

Requested Load Test Voltage - 13.400v

Actual Load Test Voltage - 12.252v

Stator Voltage at Load Voltage - 0.132v

Field Current - 0.007A

Leakage Current - 0.36mA (0.00036A)

Leakage Current After Load Test - 0.32mA (0.00032A)

Ripple Current at 2500 RPM - 58A

Lamp Voltage at Stop Condition - 2.764v

Lamp Voltage During Test - 13.799v

Pulley Ratio - 1.514

Rectifier Voltage Drop - 2.8v

Here are some pics of the alternator -

This is a picture of my current STOCK ALTERNATOR. I will have pics of the new one installed when i get it back tomorrow.

[jonbearsmt 919]

wait.. that alt has dual outputs>? is that how the OEM one is aswell.. or is that a Mechman thing?

[shizzzon 461]

I dont think so. I believe you are seeing the power and ground connections. Those terminals that are on the alt appear to be welding cable style terminals if that's suppose to be 1/0.

If it is dual output.. then there is no ground connection anywhere else on the alt...

So, i seriously doubt it.

[basebalz13 3]

hows the review?

[shizzzon 461]

Well, so far, When all the batteries are charged, i get a steady 14.0 voltage.

When any batt needs to be charged or if current is being demanded for the stereo system, the voltage sets at 14.9v.

The batts are keeping charged like they should be and i can run both of my 2200ds and my 100.4 for as long as i want to without worry.

[cjosisek90 0]

damn, im really interested in getting this now

[shizzzon 461]

They aren't some small company.

They are big business.

[mazzasec 0]

So wait what is your current electrical and what are you running? What volts do you idle at and drop to at full tilt?

[shizzzon 461]

i cant answer what voltage i drop to because i need 2 people for that and cant never get 2 people, me being 1, at a convenient time to test that out.

My electrical-

Stock battery up front.

Powermaster-

2 D5100s

1 D3100

1 250A Mechman alt

The idle output varies because if there is a need for charging at idle, the voltage will boost to 14.9v.

If there is no load present, it will idle at 14.0v.

I already posted it's current capabilities at engine speeds above.

I know you want the voltage drop but because it's so loud, i have to drive very far away to find that out and doing that plus finding somebody is an obstacle.

[danssoslow 0]

i cant answer what voltage i drop to because i need 2 people for that and cant never get 2 people, me being 1, at a convenient time to test that out.

Hell, you're in Louisville, aren't you? I'll come by; if for no other reason than to get me the hell out of this house for a little while.

[shizzzon 461]

sure i dont care

i'll pm you my phone number.

[shizzzon 461]

Ok, just go tback with the test results and here they are as follows-

When car is sitting at idle, full blast constant bass, the voltage drops 1.1v from rest point.

When car is revved to 2700rpm, full blast constant bass, the voltage drops 0.9v from rest point.

What does that mean?

IF your regulator currently read 14.9v, while driving at full tilt, you would still have worse-case scenario, 14.0v and thats with constant amperage draw from lil jon songs, for example.

IF you were at idle at 14.9v blastin it with the same type of songs, worse-case scenario would drop you down to 13.8v.

That is still higher than the float voltage of the batts so that's all alternator powering that current demand.

We didnt measure it just now but when i set these amps up via o-scope, me and a friend started to do current measurements so i could get an idea of how much power i was lookin at. Because i have high rise i nmy box, the current isnt that great from 5,000w worth of amps but the following is interesting for the alternator from what you now know above.

The most power we were able to get out of the amps clipped to hell and back in my application was about 182 amps.

So, that tells me than with 182A of draw...., PLUS whatever current my sundown 100.4 draws...., PLUS the amount of current my car draws while running... the alt can still handle it without it dipping into the batts.

That's a Hoss.

[kandiman71874 0]

good deal man, only thing you havent told us or that i cant see anywhere is what kinda bank role it set you back....

[ABXX49 20]

Yeah, I'm interested in that as well! haha

[shizzzon 461]

i guess it's ok to post this.

Retails for $649

Call them and inquire about a $50 discount.

I bought mine during group buy so the price i paid isn't what you will pay.

[-M- 0]

Nice review! That alt looks like a beast!!!

[BKOLFO4 29]

Just got mine back - Had it converted to external reg. Only a $99 option if you get t done when you order the alt. . .

[Bdunn23 0]

Ive got a 250 amp mechman as well and Im very pleased so far I have not tested it but my spec sheet that they sent with the alt looked very similar to your results so my best bet is they are very good alts

[shotta76 0]

Ive got a 250 amp mechman as well and Im very pleased so far I have not tested it but my spec sheet that they sent with the alt looked very similar to your results so my best bet is they are very good alts

The Mechman alt I have does 267 amps full tilt