Originally Posted by shantycrew
1. How can I have 18 v and 26 amps going to a fully charged engine battery
2. How can two alternators be controlled by one Next Step regulator
First off of course, stop the 18V charge before you bake your batteries, if you have not already.
Specifically, which NS do you have?
Re NS controlling two alternators. The older NS's field output circuit was designed for sufficient amps to handle this, the new ones are not. If you connect two alternators to a newer NS, it will work for a little while, but will ultimately damage the NS, which is likely what has happened. The correct way to install a newer NS with two alternators is with their "alternator driver" for the second alternator
When my old NS developed problems (after about a decade of good service), I replaced it with two newer NSs, one for each alternator
, this has the advantage of full redundancy too.
There is a thread on Ample Power's support forum about twin alternator installations. And, in my experience, their support has been excellent.