[ashley]

Richard how to tell if its the alternator or the voltage regulator

[smagown]

Did you figure it out?
If not, measure the voltage on the back of the alternator where the red positive cable is attached, first with engine off and then cranked.
Voltage should be 13.8 with engine running.
I did this recently and had to have my Penn Tex repaired.

[pairodice]

I just bought a new PennTex ($1000) ... :-(
CALL Pentex - they have great support! They will send instructions on how to check everything to see if there is a problem with the alternator or regulator (they are separate on my coach)...

[Richard]

Ashely,

Here is the link. Follow the instructions and your issue will be clarified.

http://www.penntexusa.com/1000-3000_Charging_Tests.pdf

[ashley]

Thank  you for the replies

[Land Yacht]

Hi All, I hope I am not wearing out my welcome with all the posts lately. The startup for me has been a learning curve. I do try to read on the topic prior to posting.

I have been taking short trips around the Miami, OK area, and noticed that when I drive the dash voltmeter drops below 12v. I did some troubleshooting today.
- With the battery merge on, and shore power parked, the inverter showed 13.55v, and the dash gauge 12.5v
- with battery merge off it was 12.5v
- with the merge off measured at the batteries it was 12.19v after letting it sit for a bit
- no reading at alternator with engine not running
- with the engine running at the battery measured 11.85v
- with the engine running at alternator measured 11.72v
I have a Leece-Neville alternator.
Does the above prove the alternator or regulator is bad? If so, any suggestions where to get fixed? I have seen posts with people at Big Cabin diesel, are they good?
Your help appreciated. I have less than 2 weeks to get fixed as we head back to FL on Nov 11.
Mike

[Fulltiming]

I don't know if you have the separate voltage regulator like I do but either the voltage regulator is WAY out of adjustment or the alternator is messed up. At 11.72 Volts it is not charging the batteries. It is not unusual for the dash voltmeter to read lower than the reading at the batteries. You have voltage loss over that 40+ foot run of cable from the batteries to the dash.

[Richard]

I agree with Michael. Sounds like the alternator / voltage regulator is not working as it should. You really should get 13.5 or better at the alternator and the chassis batteries.

Leave the merge switch OFF when doing any diagnosis on the alternator and that charging system. Turning the merge switch on brings the house batteries and even the house charger into play if the coach is plugged in or gennie running.

However if you are traveling and the alternator flakes out on you, you can crank the gennie, hit the merge switch and all will be well until you can address the alternator.

[encantotom]

on our trip this summer the alt/reg was putting out under 12 volts a good share of the time. i talked to steve bare and he said the same as richard, just run the genny and merge switch on and you can go forever. i did most of the trip for 6 weeks that way. mine was the regulator which i changed and all is well now.

tom

[jcus]

on our trip this summer the alt/reg was putting out under 12 volts a good share of the time.  i talked to steve bare and he said the same as richard,  just run the genny and merge switch on and you can go forever.  i did most of the trip for 6 weeks that way.  mine was the regulator which i changed and all is well now.  

tom

I have done the same, a plus for having solar, on a sunny day, did not have to run gen. at all. 45 amps from
panels handled it. Of course at night, generator on.
Jim