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overcharging

PostPosted: Thu Oct 01, 2015 7:46 am
by Jruss
I have two Next Step regulators driving two Hitachi 80 amp alternators on a pair of Yamaha diesels on a catamaran. Both alternators charge a single house bank (6 105 amp AGM's) and one starting battery each. I have overcharging ( 15 V) on the starboard alternator. When this occurs, the port regulator LED's show green, solid and red flashing 6, 3 voltage runaway. The starboard regulator is green, solid with no red errors showing. When I shut down the port engine, the starboard regulator drops back to flashing green.
Voltage readings appear normal (I can post if that would be helpful), and connections seem clean and tight.
Since I understand that "best practice" now is to use one regulator rather than two, can I rewire my system to the single regulator and order the dual alternator controller? Or should I upgrade to the NS 2 with the DAC? Or repair what I have?
The boat is 9 years old. though "new" to me...
Thank you for your help.

John Russ

Re: overcharging

PostPosted: Mon Oct 05, 2015 7:57 pm
by Coulomb
You can't charge one battery with two regulators. The one with the lowest set point will signal overcharge.

You need the SARV3 and A DAC to regulate two alternators on two engines. The Next Step and NS2 are not rated to drive two alternators.

Re: overcharging

PostPosted: Tue Oct 06, 2015 12:03 pm
by Jruss
Ok, Thanks for the information. Before I pursue that option, I just want to be sure that you know that I am installing in a catamaran. The Regulator Comparison, SAR V3 and NS2 document suggests that the "V3/DAC method less than optimum." for catamaran installs.
Thank you!
John Russ

Re: overcharging

PostPosted: Tue Oct 06, 2015 3:19 pm
by Coulomb
Unfortunately the Driver Module was discontinued due to lack of interest.

You can keep RFI down by twisting the field wire to each alternator with a ground wire which is connected to ground at only one end of the wire -- preferably at the battery negative distribution point.