12 volt electrical question

[JackConrad]

Yesterday while driving to Palmetto Cove, I noticed our 12 volt voltmeter (house batteries) bouncing between 14 and 15.5 volts. I pulled over and removed the belt sow e could continue to the Cove. House bank is 8  6 volt golf cart batteries that were topped off, cleaned, reinstalled, and all connections cleaned and tightened just before this trip began (3/5). The alternator is a 1 wire auto type alternator.  My question is, does this sound like the regulator that is built in the alternator has failed or is there another possible problem?  I am going to stop by an Auto Zone, Pep Boys, etc. this morning to see if the regulator operation part of the alternator can be bench tested.  Thanks in advance,  Jack

PS: I am posting this on both BBs to get more information

[gumpy]

Hmm.  My first inclination is maybe a short in something that is tripping an automatic reset circuit breaker. The short causes the voltage to drop, and then when the breaker trips, the voltage
goes back up. Then the breaker resets and the cycle starts over.  Do you have a shunt and amp meter in the system?  How much current is being drawn and does it fluctuate with the voltage?
If so, try disconnecting all loads from the bank and see what the alternator does just charging the batteries.

[JackConrad]

With the belt removed, the volt meter stays at 12.5 volts with no deflections.  With the belt is place, the inverter panel showed a fault (high voltage). With belt removed, inverter panel showed normal readings.  Jack

[buswarrior]

My first suspicion would be the gauge, not the alternator.

Until I read your second post that the inverter is angry too...

happy coaching!
buswarrior

[rv_safetyman]

Jack, since the batteries are golf cart, you can check the cells with a hydrometer.  I don't have much experience with this, but folks have posted that a bad cell or two can fool the alternator into full charge. 

Jim

[kyle4501]

I'd be suspect of the voltage regulator inside the alternator. Spinning it on a bench won't be the same as bolted to a screamin' jimmy - heat & vibration.

What is the cost of a new alternator?

[luvrbus]

Most of the time that is caused by a open circuit check all your grounds and could be a bad diode in the alternator.   


good luck

[HighTechRedneck]

My bet is on the diode.  Last week I had to replace the alternator in my pickup with similar behavior.  With no cause it would toggle between 14.8 and not charging.  It was a bad diode.

A local alternator shop could repair and load test it for about $40.  But the alternator was getting pretty old and I found a good deal on a fully rebuilt one with a one year warranty for $80 at Auto Zone so I went that route.  Problem solved.

But as new as your alternator is and the fact it is quite a bit more expensive than the little one on my Toyota pickup, you may want to see if there is an alternator shop within reasonable distance.

[gumpy]

Either bad battery in the bank, or alternator regulator.  Check the batteries.  May be a bad cell, as Tom said. 

Is it possible to connect a different battery to the alternator to test it in the same configuration without the big bank?

[Jerry32]

The regulator should not let voltage go over 14.2  if working right. I would have them test the alternato in the rig as it sounds like the alternator regulator is at fault Jerry

[uncle ned]

Jack   just get with Leroy at Palmetto Cove. I think he knows a good alternator man. If not i will bring a good les neville down.

See all in the morning

ned sanders