1GM10 Charge Light ON, Batteries Charging

Jun 14, 2015
10
Hunter Hunter 27_89-94 Belleville, ON
Hi,
Hoping I can get some advice on this. When I start my 1GM10 the charge light remains on, although very dim, but the batteries are charging. There is no audible alarm associated. I measure just under 14v with the engine running.
Any ideas on where the problem could be? I have the Yanmar 'B' engine instrument panel.
Mark
 
Jan 7, 2015
77
Menger 19 Catboat Annapolis, MD
Because of the small power output of the 1GM10 at idle, the pulley on the alternator is sized so that there is no charging current at idle to avoid loading the engine. On mine the charge light is on at idle and goes off as soon as the engine is revved slightly. I believe that is normal for this engine.
 
Jun 14, 2015
10
Hunter Hunter 27_89-94 Belleville, ON
Thanks for the advice. With the engine running at 2000 rpm the charge light is still on. The voltage measured at the battery during this time is 13.74v. Perhaps this is a bit low as Benny suggests. I'll remove the alternator and have it tested. Any idea what triggers this light? Is it a minimum voltage threshold?
Mark
 

Attachments

pateco

.
Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
I have the same problem but different symptoms. My Yanmar 2GM charge light goes on when started, but gets brighter with increasing RPMs. I am getting good charging at 14.2V, and good regulation (for a Hitachi). Higher amps with a lower SOC and then decreasing as the battery comes up to 100%

What could be the wiring issue?
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
More often than not, unusual electrical system issues such as you both described are a result of either:
1. Battery and charger (alternator) problems, or
2. Poor, high resistance connections somewhere in the chain.
 

pateco

.
Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
Sorry to be so confused. I understand that the lamp provides field power to the alternator at starting once the ignition key is on, but what normally would make the light go out once the engine is started and running? The sense wire, or something else?
 

pateco

.
Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
I never got an answer to this, and it is still occurring. The charge light is always on while the engine is running, but the alternator is definitely charging the batteries.This last weekend when I was doing my two local holiday boat parades I was running all of my interior lights, and bot running and steaming lights, along with a 1200 watt inverter powering 20 strands of led Christmas lights, and a 1000 watt audio amplifier and mixer. My Victron battery monitor showed I was using about 14 amps off the battery with the engine off, 2.5 amps of battery at idle, and that at 2800 RPMs I was charging the batteries at about 9 amps even with the external loads.

How do I make this light work correctly?
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
What it means is there is less resistance thru the tri-diode and lamp than the rectifier path. If/when the lamp burns out your regulator will fry. Look for bad cables/connections between the battery and alternator.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
Have you taken the alternator/regulator to a alternator shop (not a auto parts store)?? Testing will be nominal or free.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Worn brushes could be one reason.
Really? In an alternator, only the field excitation current is carried by the brushes, or slip rings. If the system was within regulation, the regulator would increase the field current to increase the alt. output voltage. Isn't that so?