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Alternator low volts; Nest Step regulator bad field voltage

PostPosted: Fri Aug 13, 2010 8:18 am
by SheltieJim
I've got an Ample Power power monitor, a Next Step regulator, and a 3rd party alternator on my sailboat. I recently discovered that the engine would not fully charge my batteries; it would charge them to only about 12.65 volts. My first action was to measure the voltage that the alternator was putting out and, sure enough, it was putting out only about 12.65 volts. A little research on this bulletin board showed me how to check the regulator voltages. Here are those results (for each pin, I've cited the voltage with the ignition switch off, then with the switch on, then with the engine running):

House battery: 12.70, 12.79, 12.65
Parallel: 12.7 12.68, 12.65
On/Off: 0, 11.96, 12.05
Gnd: 0, 0, 0
B+: 12.71, 12.68, 12.53
Field: 5.03, 5.57*, 5.54*
Alt Gnd: 0, 0, 0
Lock: 0, 0, 0
Batt Volts: 12.71, 12.67, 12.65
T-: 0, 0, 0
T+: 0, 2.94, 2.95
ABS: 0, 8.38, 8,38
Lamp: 0, 0.30, 0

* When the ignition switch was on (both without the engine running and with it running), the voltage on the Field pin mostly showed the voltage given, but about once a second the voltage would jump very briefly to a number in the 7, 8, or 9 volt range. It happened to fast to really read the meter, though.

I suspect that the Field voltages are a strong indication that the regulator has gone bad. Should I try to have it fixed, or just purchase a replacement?

Also, does the (possibly) bad regulator have anything to do with the low voltage that I see coming from the alternator? The alternator is rated to put out at least 14 volts.

Strangly enough -- and perhaps merely coincidentally -- my bank of solar panels, nominally 16.5 volts, also seem to be putting out only 12.3 volts into a FlexCharge NC25A-12 regulator. Any suggestions on this problem?

Thanks!
Jim

Re: Alternator low volts; Nest Step regulator bad field voltage

PostPosted: Fri Aug 13, 2010 2:31 pm
by Coulomb
It appears the regulator is defective - not enough field voltage. Repair is generally $170 - $200.00.

The solar panels may be charging, but with a discharged battery, may not be able to drive the voltage any higher.

Send products for repair to:

Ample Power Company, LLC.
6315 Seaview Avenue, NW
Seattle, WA 98107

Re: Alternator low volts; Nest Step regulator bad field voltage

PostPosted: Mon Aug 16, 2010 1:52 pm
by SheltieJim
Thanks for the response. Your answer about the solar cells proved to be correct. We're debating whether to have this regulator repaired or to purchase a new one.

Re: Alternator low volts; Nest Step regulator bad field voltage

PostPosted: Mon Aug 16, 2010 3:22 pm
by Coulomb
There is a trade-in allowance for either an NS2 or SAR V3. Send an email to ruth@the usual for a quote.