Voltage oscillations while charging

[John Langford]

I still have a 1998 Heart Interface incharge external regulator managing a Leece Neville 105 amp alternator. This has worked well overall for 17 years. I cruise for two to three weeks at a time with occasional nights at marinas. I only rarely take my 4 Trojan 105 house bank down below 100 amp hours so my bulk charge rate never exceeds 60-70amps with the voltage set at 14.6 or so. The alternator seems to run at a reasonable temperature but I don't monitor that electronically.

To this point, the only odd things I have noticed are tach oscillations and erratic voltage and current readings on my e-meter at startup when the battery bank is fully charged after a night on the AC battery charger. This seems to stop after a few minutes of running when I add loads like the blower or the frig starts cycling. I don't understand this but I believe others have reported similar phenomena. To this point I have been just living with it.

However, recently I have noticed that the voltmeter at the helm is quivering most of the time when the alternator is bulk charging and the e-meter tells me that the voltage is jumping around between 14.50 and 14.85. The belt is tight and there is no slippage.

So here is my question. I think this a new development.  Does anyone know if that much oscillation in voltage is something to be concerned about?

[Stu Jackson]

1.  I don't understand this but I believe others have reported similar phenomena. To this point I have been just living with it.

2.  However, recently I have noticed that the voltmeter at the helm is quivering most of the time when the alternator is bulk charging and the e-meter tells me that the voltage is jumping around between 14.50 and 14.85. The belt is tight and there is no slippage.

So here is my question. I think this a new development.  Does anyone know if that much oscillation in voltage is something to be concerned about?

1.  The reason, not a phenomena, is that the regulator is seeing the batteries as FULL.  Once full it cuts back the AO.

2.  My panel voltmeter jumps when the autopilot operates.  I attribute this, on my boat, to the fact that when the PO had it installed, the installer chose to tap the AP power off the panel power wire.  It could be any number of things on your boat:  loads starting always drop the voltage.  However, in electrical, any time and almost every time there is intermittent operation of anything, it is due to loose or poor or deteriorating connections.

Good luck.

[John Langford]

Thanks for the quick and thoughtful response Stu. I will check for dodgy connections between the regulator and the alternator. The interesting thing is that so far this oscillation in voltage levels recorded by the e-meter is constant rather than intermittent. Also, it doesn't seem to affect the charging capacity of the system. It just bounces around between about 14.50 and14.85 without, to this point, adversely affecting charging performance.

[Noah]

Possibly the meter too?

[John Langford]

Thanks Noah. I don't think it's the e-meter. I should have mentioned that it is rock solid when tracking the activities of the onboard Xantrex 20 amp battery charger.