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Next Step NEXT-12P field current problem

PostPosted: Wed Jun 17, 2009 9:01 am
by wongsters
I have been having a problem with my regulator on my boat which is supplying a field current to my alternator even when the ignition switch is off - the current drain is about 2.5A - something which was not a problem before.

I have taken some readings as follows:

House battery: 13.0V(Ignition off)/13.0V/(Ignition on)/16.8V(Engine running)
On/Off:0.0V/11.3V/12.7V
Ground:0.0V/0.0V/13.2V
B+:13.0V/13.0V/14.2V
Field: 12.8V/12.8V/12.8V
Alt Gnd: 0.0V/0.0V/-0.5V
Batt Volts: 13.0V/13.0V/16.8V
T-:0.0V/0.0V/0.0V
T+:0.0V/3.0V/4.8V

The battery had recently been charged via shore power, hence the 13.0V reading initially.

Clearly something is amiss, particularly as there was a strong smell of acid after a few minutes of the engine running, which I presume was the result of gassing because the voltage was too high (16.8V).

Is there something I can fix myself or is the regulator faulty and hence has to be returned to Ample Power for servicing?

Many thanks for your help.
Steven

Re: Next Step NEXT-12P field current problem

PostPosted: Wed Jun 17, 2009 10:37 am
by Coulomb
Anytime the field voltage doesn't go off with the ignition switch, the field circuit is at fault. Usually they can be repaired, however there have been cases where the copper trace on the printed circuit board has been burned out. It takes a big transient to do this - probably a lightning strike.

Another source of a transient big enough to blow the regulator and other onboard electronics is a battery selector switch that is turned off when the engine is running, or decides to open up itself. See this URL: http://www.amplepower.com/apps/burnt_sw/index.html.

More information about repair can be found here: http://www.amplepower.com/support/index.html

Re: Next Step NEXT-12P field current problem

PostPosted: Fri Mar 19, 2010 9:11 am
by nando64
I have a 20 year old 3 step voltage regulator that has always worked well. Recently I have not been using the boat as much and i noticed when I came aboard that the ample power monitor was displaying a 3 amp drain from each house battery for a total of 6 amps. Of course the batteries were down even though I have 2 solar panels solar module SM 50. which always has keep the batteries top off.
Where do I start to determine where this drain is coming from.
I am not sure is the solar cells are not putting out or I have a problem with the voltage regulator or high out put alternator.

Any help would be appreciated.

Re: Next Step NEXT-12P field current problem

PostPosted: Fri Mar 19, 2010 11:21 am
by Coulomb
The regulator has a field driver short. The 3-Step Regulator has not been made for many years. You can upgrade to the Next Step 2 Regulator.

There is a trade-in allowance.

Re: Next Step NEXT-12P field current problem

PostPosted: Sun Mar 21, 2010 12:02 pm
by nando64
Thank you for your help. What is the price of the new regulator and will it attach to my system without any electrical problems.

Re: Next Step NEXT-12P field current problem

PostPosted: Mon Mar 22, 2010 11:46 am
by Coulomb
The NS2 uses the same set of wires, but instead of spade lugs, the wire are stripped and inserted into a terminal block. That means cutting off the spade lugs and stripping the wire ends.

Contact ruth the_usual_at_amplepower.com for pricing.

Re: Next Step NEXT-12P field current problem

PostPosted: Wed Mar 24, 2010 1:11 pm
by nando64
I have 12 wires going to the voltage regulator and one of them is hot. I diconnected the hot wire and when I turned the batteries back on I still had the 7 or 8 amp drain on the batteries. Can you help me better understand if their is an internal short in the regulator should I disconnect all the wires to see if that stops the drain on the batteries.
Thank you for your help.

Re: Next Step NEXT-12P field current problem

PostPosted: Fri Mar 26, 2010 10:40 am
by Coulomb
You can do that, but start with the ones that supply power.

See: http://www.amplepower.com/wire/next/nextp.html and http://www.amplepower.com/trouble/index.html

Re: Next Step NEXT-12P field current problem

PostPosted: Mon Mar 29, 2010 6:37 pm
by nando64
My Question is.

Since I have disconnected the hot wire to the 3 step voltage regulator and I still have the 8 amp drain on the batteries does that men that there is no short in the regulator?
Or must I do something else before I order a new regulator.
Enclosed is a photo of the voltage regulator.

Re: Next Step NEXT-12P field current problem

PostPosted: Wed Mar 31, 2010 12:08 pm
by Coulomb
This is not a Next Step Regulator. It's an ancient 3-Step Regulator, late 1980s vintage.

Time for an upgrade.