mechman alt issues

[East 10+ year member]

I just got a 250a mechman alternator and did the big 3 have an odyssey pc1500 battery it rests at 12.6v and i get 14.2v engine on idle. I did a clamp and im getting 120a @ 600rpm idle and 140a at 800rpm. My problem is my lighta dim bad and voltage drpps to 13.5v on my nendo 2000 also after 30 seconds of the car running the alt os too hot to touch. Just felt like itd be better for what i paid considering stinger and powerbastards had one for mucj cheaper claiming the same numbers. Thw sheet for my alt said 166 at 800 and im only seeing 140...

This all normal also how mucj is it to raise my idle on the pcm in a shop? I figured a crescendo 2000 would be hilds play on my electrical.

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[av83 10+ year member]

I just got a 250a mechman alternator and did the big 3 have an odyssey pc1500 battery it rests at 12.6v and i get 14.2v engine on idle. I did a clamp and im getting 120a @ 600rpm idle and 140a at 800rpm. My problem is my lighta dim bad and voltage drpps to 13.5v on my nendo 2000 also after 30 seconds of the car running the alt os too hot to touch. Just felt like itd be better for what i paid considering stinger and powerbastards had one for mucj cheaper claiming the same numbers. Thw sheet for my alt said 166 at 800 and im only seeing 140...
This all normal also how mucj is it to raise my idle on the pcm in a shop? I figured a crescendo 2000 would be hilds play on my electrical.

What do your ring terminal connections look like? Where area your big three grounds?

 

[tc300 10+ year member]

Doule check all your wiring/grounds...

 

[East 10+ year member]

Wiring is all knukonceptz 0 gauge with nice terminals i have the alt grounded to the batt neg and the power on the batt power those were mechmans instructions.

Basicallu just ran the alt power to the batt pos and then put the batt neg to the alt bracket.

 

[East 10+ year member]

Do i need to ground my batt to chassis the instructions mech sent told me to do it the way i did it. Just dont understand why its hotter than my stock 150 was and why my voltage doesnt seem mich better im happy with 13.5v idle full tilt but i did expect more considering he claimed 166a 800rpms and im seeing about 30a less with a new gatorback belt and proper big 3.

 

[SounDrive Pro Seller]

Where is your chassis ground on your big 3? I had very similar electrical on an amp 50% larger and I had almost no voltage drop.. My last build was a m3a with a Mechman 240a and Duracell AGM.

 

[yogegoy]

Did you clean the inside bore of the mounting bolts and the bolt itself with spiral wire brush and placed batt red stuff in it? Every mating surface should have a clean metal surface, same thing goes with the 1/0 neg cable to the mounting bracket. Help your connections getting too much resistance, clean bare metal mating and clamp it tight (hand tight plus 90*). My 370A Mechman is just wonderful at every engine speed, always giving me a healthy dose of 14.6V and 13.8V at idle. If you can solder the pos and neg cables to your battery terminals (and all terminals) you'd see a big improvement specially in the mechanical noise in the system.

 

[East 10+ year member]

Im pretty sure surfaces are clea.

N and i dont have a chassis ground cause mechman didnt list it on the install sheet. Also do your guyses alts run hot?

 

[East 10+ year member]

Literally the paper said connect wire from alt pos to batt pos and from alt bracket to batt neg. Doesny say to change the chassis ground all my cables connectors are new and professionally crimped and installed all surfaces are clean. Bely is to spec and was recommended by mechman. So im confused at the low voltage and amperage and the scorching heat. Maybe ill make a vid tommorow.

 

[SounDrive Pro Seller]

Literally the paper said connect wire from alt pos to batt pos and from alt bracket to batt neg. Doesny say to change the chassis ground all my cables connectors are new and professionally crimped and installed all surfaces are clean. Bely is to spec and was recommended by mechman. So im confused at the low voltage and amperage and the scorching heat. Maybe ill make a vid tommorow.

If your big 3 isn't good then the alternator won't perform well. Show us all the wiring you've done under the hood.

 

[brian84corvette 10+ year member]

add ground from engine block to frame - and also from battery negative to frame.

as stated above

take off your existing ground - and clean with a wire brush until its super shiny clean metal - clean the ring terminals and bolts / nuts / washers ext..

try to imagine yourself as negative electrical flow on your entire viechle. you want to get to battery negative but its hard for you to pass thru conections that are dirty.... haha - now go search your car for grounds of negative and clean them all. torque them down good when re installing.

i had an issue with voltage drop until i realized the fuze in my alt charge wire was not holding correctly in the spring bracket crap there was in the block - threw that piece away and got a propper anl style fuze with allen bolts. since then ive seen much less voltage drop...

 

[East 10+ year member]

So of i need addition grounds why didnt he list em? Also all my shits clean this isnt my first install lol.

 

[yogegoy]

It's all just a suggestion where to look first, that's all.

 

[East 10+ year member]

Does anyone elses mechmans get too hot to toucb?

 

[NASTY08IMPALA 5,000+ posts]

Does anyone elses mechmans get too hot to toucb?

Yes all alts get too hot to touch and those smaller case mechmans dont put out much power below 2000rpm ..my 240 did 143 @900 and 244@2k ..doesnt sound like much wrong ..just not much output at idle