Swapping out old Next 12-P for NP2

[dpkoestner]

After an apparent voltage spike damaged my old Next Step (the 12P, which was giving me a Bat Volts Disconnected error message while the cable was connected and supplying proper voltage to the regulator), I recently installed the NS2, using the original wiring from the previous installation on to TB1.

Having adjusted the set points using a digital meter, I’m now getting a Voltage Runaway error message, though I have no other charging device presently online. I do use a solar panel I clip to the house battery when I leave the boat, an early seventies vintage sloop, on her mooring for extended periods, but I disconnected it. The house bank is currently reading around 12.8V, thanks to the solar panel.

I do have a Xantrex echo charger online, as well as a Xantrex battery monitor. These were all initially installed along with the Next-12P and an Ample Power 4023 alternator by a licensed marine electrician in 2005. All ran smoothly until I noticed the alternator kicking out of bulk charge about fifteen seconds after engine startup, at which point I discovered the error light and net current loss on the monitor.

I have yet to try starting the engine, being unsure of the potential hazards given this error warning. Nor have I run the complete troubleshoot test. I was hoping this info might be sufficient.

It has entered my mind that this newer unit (NS2) might be confused by the presence of the Xantrex echo charger since I believe it is itself designed to handle such duties with the proper optional solenoid. I should also mention the reason I believe a voltage spike was involved. We had recently connected to shore power, something we’d never done before, and noticed the electrician had essentially hotwired a previously installed AC-powered charger into the system, which came online when we plugged in. I didn’t think much of it until we also later discovered a blown fuse on the echo charger. Generally our boat sits on a mooring.

[Coulomb]

Something isn't right with the system - too many failures. The charger wiring may be incorrect and the prime cause of the problems.

It would be a good idea to take measurements on all the NS2 pins, once with ignition off and then again with it on.

[dpkoestner]

I wanted to follow up for those who might find themselves facing the same issues.

My situation is resolved following an interesting discovery. It turns out the digital meter I'd used to adjust the set points was giving false high readings, most probably because of a failing battery that powers it. I'd become suspicious after using it to test a few things, and so I plugged it into a wall outlet at home, to discover I had 150V AC service. THEN the low battery warning came on.

Here is what I figure happened. Dialing down the set points to read 1.44V & 1.38V, I was sending the actual values much lower, thus triggering the regulator to issue a voltage runaway condition. 12.6V was more than .5V higher than it had been programmed to accept as proper.

New multimeter battery, tested against a second meter, and the NS2 is now communicating nicely with the alternator.

[Coulomb]

Great troubleshooting! We all have too much faith in our meters.

Thanks for reporting the results.

[dpkoestner]

One final question. As I've said, I feel fairly confident some circuit got fried in the old regulator. Given the advantages of redundancy on a cruising boat, might it be cost effective to have the old regulator looked at for repair purposes? These are, after all, costly devices to replace, and the old unit did an admirable job for years (and I know how to wire it). I'd like a sense of what it might cost.

Thanks for the help on this board.

[Coulomb]

Cost to repair is generally $140 to $175, shipping not included in these.