Thread: 2nd alternator and battery

You will need a voltage regulator for the separate cirquit, so the battery doesn't get overcharged (unless it's already integrated into the alternator).

Good luck!

Joachim

I have never seen a 3-wire alternator that is not internally regulated.

Originally Posted by ozzy71

I have never seen a 3-wire alternator that is not internally regulated.

How do I know if its internally regulated? If it helps it of a mid 80's Caddy. Its already mounted on the truck so i can test whatever
Thanks

If this unit indeed came off of a 1987 deville:

It is a 120amp unit and it is externally regulated.

Here are some photos of things to look for:

3-wire connector:

Rear-photo of alternator

photo of external regulator

Your regulator may already be on your alternator. Any chance you can upload a photo of your alternator?? I mostly need the rear of the unit.

Also, do you already have the 3-wire pigtail? Keep in mind the photos I am showing you are from an autoparts store's online information-- so I need you to verify that it is correct.

I built a battery isolator and installed a 2nd battery in my shoebox scion for $10... it works perfectly... and is easy to do.

How about just upgrading your current alternator?

Get a high output alternator and replace your stock one.

Then rip out that wire you did for the big 3 and use 0awg.

Then get an Optima battery to replace your current one.


That should help out quite a bit. If you STILL get dimming, then think about maybe a second alt. I had around 3k watts worth of amp in my old car and it did not dim using what I just described above.

I had a 200 amp alternator.