voltage loss

[stevea661]

The boat is an 86 268 with a 5.7 omc. After I changed the alternator the other day I was testing charging voltage. The battery was steady at 15.5 volts. The alternator is a 3 wire type. I checked the voltage at the sense wire and it was 14.5 volts, so the internal voltage regulator was doing what it was suposed to do. I started checking voltage through the circut and by the time the wire goes up to the key and comes back to the alternator I am loosing one volt. In searching on the internet and speaking with several people I figured out that running the sense wire to the bat wire on the alternator would give the alternator a better Idea of the state of charge of the battery it was servicing. Which it did. As soon as I made the change the voltage at the battery and alternator was at 14.5, this solves any over charging problem. The voltage up at the switch was 13.5 so I am still loosing one volt through wiring, ignition switch, connectors, etc. So my question is, is this a big deal:huh:. I'm ok with it. But I'm not a boat electrician, just some guy with a meter. Do any of you guys out there have any thoughts on this?
Any input would be apreciated. Thanks in advance

 

[Mr Salt]

You will have some voltage loss as electricity travels. The loss will depend on the length of the run, in boats that is twice the one way distance, as well as the wire guage. There are two voltage drops that are acceptable 3% and 10% over the run. The 3% drop is used for any critical electrical components such as bilge pumps, electronics, nav lights and any other item deemed critical for the safety of the vessel and its occupants. The 10% voltage drop is acceptable gfor all other applications. A 10% drop is permitted for non critical applications.

It would appear to me that the voltage drop for the application you are talking about is within the permitted range and would be permitted by ABYC. I would however, suggeat the you go out to www.marinco.com and look at the wiring specifications. This will give you a better understanding and you can check to see that the wire sizes used are correct for the apllication.

 

[stevea661]

You will have some voltage loss as electricity travels. The loss will depend on the length of the run, in boats that is twice the one way distance, as well as the wire guage. There are two voltage drops that are acceptable 3% and 10% over the run. The 3% drop is used for any critical electrical components such as bilge pumps, electronics, nav lights and any other item deemed critical for the safety of the vessel and its occupants. The 10% voltage drop is acceptable gfor all other applications. A 10% drop is permitted for non critical applications.

It would appear to me that the voltage drop for the application you are talking about is within the permitted range and would be permitted by ABYC. I would however, suggeat the you go out to www.marinco.com and look at the wiring specifications. This will give you a better understanding and you can check to see that the wire sizes used are correct for the apllication.

Sounds about right. Thanks