Voltage problem

rick1954 · Post by **rick1954** » Mon Jul 20, 2009 9:25 am

Okey, every one, I still have a minor problem with the radio. The out put of my alternator is 15.2 vdc no load, full load it is 14.8vdc. This is well within spec for this unit, however, my radio is telling me that the voltage is high, it does not want to see anything over 14.3vdc. Can I build or purchase a regulator hat I can put in line with the radio to keep the power feeding the radio at a constant. Such as using a 15 volt Zener diode that would have a voltage drop of 0.7vdc.

Stripermann2 · Post by **Stripermann2** » Mon Jul 20, 2009 10:21 am

Sounds as though you have a bad voltage regulator in the charging system.

A good charging system should be between 13.5- 14.2 volts, with an acceptable amperage output, rated for the alternator at say 2000 rpm or per factory given rpm with a load. (eg; 100 amps)
If this is a Chrysler system, and it has a external VR, then I would look into this first. They were prone to going bad.

rick1954 · Post by **rick1954** » Mon Jul 20, 2009 10:48 am

One would think that about the regulator being bad, however it maintains a constant voltage on full load and no load regardless the rpm. This is telling me that the reg is functioning I would think. As I stated , the voltage meter on the boat is telling me that the voltage is within spec also. Everything I have running on 12 volt seems to operate ok â€œso farâ€
No the alternator has an internal reg, I think I should investigate this alternator to see if it is indeed a marine unit, I was told that an auto unit will put out anything from 13 something ,up to 16vdc. Something sounds fishy.

Thanks

Stripermann2 · Post by **Stripermann2** » Mon Jul 20, 2009 11:18 am

I would replace the alternator and regulator (one unit) Sounds like system is almost full-fielded.

The VR switches current some several hundred times per second, to obtain and maintain proper voltage. It still sounds like it's over charging.

Another thought would be a sulfated battery with say 15 volts or more, with no load. Too much alternating current will damage the battery. Check and be sure. Good luck-

rossjo · Post by **rossjo** » Mon Jul 20, 2009 11:27 am

Make sure you have a Marine Alternator. Marine alternators are designed to be explosion proof so that brush sparking will not ignite explosive gas mixtures in an engine room environment. Many older boats have had their alternators replaced with cheaper automotive units, which are not safe.

What does you portable Volt-meter read? You shouldn't be hitting 15VDC any time - as most of your components (do you burn up a lot of bulbs?) are not designed for that much voltage.

guglielmo6160 · Post by **guglielmo6160** » Tue Jul 21, 2009 10:50 pm

your putting out to much voltage and the problem should be corrected as other problems may arise from that, you have a bad regulator already either the alternator or seperate regulator whatever system you have