DC Voltage

[Eddy G]

I've noticed while breaking in my new Yanmars that the volt meters are showing from 14.5 to close to 15 volts while the engines are running. The gauges are new VDOs, the batteries are just over two years old and the alternator wire is connected to the same source as the volt meters up at the helm. I checked the voltage at the battery terminals (at idle) with a multimeter and got about 14.5 volts. I thought that around 13.8 to 14 would be correct. Is 14.5 to 14.9 too high? I'm going to do some more checking this weekend and problably replace the batteries before I do anything else. By the way, the battery set up is two Delco Mariner deep cycle Group 27's in parallel per side. What voltage should I be seeing while running? Thanks.

Eddy G.

[In Memory of Vicroy]

Eddy, you may be ok since the deep cycles will make the voltage regulator "see" a bigger load to charge. My guess would be your on board charger is not "topping" them off and the alternators are trying to. I have the same situation on 21 KW home genset - the little trickle charger holds the deep cycle at about 12.8 v. but when I start the set the voltmeter will go to about 14.5 from the alternator output.

Another thought is to turn off your on board charger with the engines running and see what you get.....a bad diode in the charger could make the alrternator voltage regulators "see" a deeper load.

I'll be around the camp this weekend - stop by for a clear.

UV

[Eddy G]

Vic, your theory sounds right. I have only run the boat a couple of times for more than an hour straight and the voltage did come down some, but not much. I'll turn off the charger and see if it make a difference. I'm going to check the voltage at the batteries with only the on board charger on for a week. I'll also check the alternator wire voltage at the engine to make sure there isn't a voltage drop between the alt and the dash panel. I hope to get back to the Tickfaw real soon. Didn't make it for Mardi Gras. You need to run AJ over to our side some day and join us for lunch. Thanks for the help.

Eddy G.