adding second alt failure

[needmobass 0]

So maybe some one here has done 2 alts can help me.

just came back from my mechanics shop and was told that adding second alt would not work, i asked why and was told he could install but could not turn alt on, said i needed a wire harness to hook up to trucks computer. I thought the belt turned the alt on and i could wire to rear batt bank.

Can anyone with this type of knowledge please help me out? (air con being swapped for stock alt to go with my Mechman 270a alt)

[shizzzon 461]

yep, he's right.

You need a wire harness. Contact Mechman for one.

[needmobass 0]

just emailed him. thanks again shizzon

[Skullz 8]

You can hit up a JY and snag a plug with a nice length of wire and splice into your harness matching wire for wire and should be fine, just make sure you seal the wires so they won't corrode.

[Tirefryr 1,742]

What you need is a sefl-exciting alternator, or get a self-exciting regulator for the alt you currently have. The only wire needed is the positive to the post on the back.

[Tirefryr 1,742]

You don't want the secondary alt to communicate with the computer, only the stock unit. The ECM will not be able to control two units, only one, and if he tries to splice the new alt in with the old, it will cause issues. Any GOOD mechanic will know this and would have told you just to get a self-exciter.

[needmobass 0]

Tirefryr---ok please explain what a self-exciting regulator/self-exciting alt is and where i can get one.

that sounds like it would be the best option for me

[needmobass 0]

So i googled self exciting alt and found a website called quick start high output alternater am i on the right path?

They have self exciting alts for decent price.

[Tirefryr 1,742]

The Mechman is your second alt your adding? if so, call them up and ask them if you can get a self-exciting unit in exchange. An alternator needs current to "turn on." With a self-exciting reg, it's basically jumpered internally to the battery post meaning there is always current going to the "turn on" of the regulator, so it essentially turns itself on. No other wiring is needed. You just bolt the alt in, hook up the battery cable and you're good to go.

Your stock alternator uses computers or just different wiring to control the regulator, warning lights, voltage gauge, etc. Since you are keeping the stock alt, the computer will be satisfied there and use the stock alt to handle it's duties. You don't need any of that stuff on the accessory alt, so self-exciting is the way to go.

[needmobass 0]

The thing is that i got the mechman over a year ago, and thats what is on the truck now , i was wanting to reinstall the stock one till i can afford a second mechman

[Tirefryr 1,742]

Just reinstall the stock one and use your mechman you have now as the second alt. Call them up and see if they'll R&R it and install a self-exciting regulator. Shouldn't cost more than $100; far cheaper than a new alternator.

[needmobass 0]

I didnt know they could even do that. will that alter the current amperage of 270, and would it be best to call them or email them since im sure they are always busy, guess ill find out tomorrow Thank you sooooooo much you made my day , i just hope all of this is possible without waiting months

[Shogen 325]

call them...

[needmobass 0]

Cant till tomorrow ,im sure they are closed for the day

[Shogen 325]

yes, that is what I meant... tomorrow morning or afternoon... no later than 3pm .. I think they get to the phones pretty good.. Only left a message one time and I still got a call back at 6pm ... But not common..

[needmobass 0]

Then i'll call first thing in morrning. im on the east coast so i will call around noon.

[Tirefryr 1,742]

IT will not alter the output. It simply starts charging as soon as the alt it spinning and negates the need for any other wiring.

[needmobass 0]

I found my solution, well you did, but im gonna be a happy camper when and if they do it.

Cant wait till tommorow well i have i guess, im psyched. Thanks again............