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best way to find a faulty regulator or isolator

January 15, 2014, 02:39:55 am

I'm looking at these couple items and know nothing about what size they are or how you'd even go into a store and buy them. They must have numbers on them for specific needs. Can someone let me know first....how to check the isolator, then, how to test a regulator mounted on the same mounting plate with the isolator?  ( its there on that mounting plate is where the Trik L Start is mounted as well )

I'm not doing much with her right now but will want to at least evaluate things in the days to come so I know what's next for replacing.

Any methods or helpful testing or replacing tips are welcomed...please

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Re: best way to find a faulty regulator or isolator

Reply #1 – January 15, 2014, 07:52:47 am

Carl,

With engine off, shore power and generator off, check voltage with a digital voltmeter at the two outer lugs of the isolator.  Each one goes to a battery bank-- one to the house bank, one to the chassis batteries.  Verify that voltage is the same as at their respective batteries.

Start the engine. Go to high idle (1100 to 1200 RPM).  Check voltage at the two outer lugs and at the center lug with the large wire coming from the alternator B+ terminal.  Voltage at the two outer lugs should be 13.5- 14.2 VDC. The B+ terminal on the alternator and its lug on the isolator should be about .7 VDC higher.

This will tell you if the alternator, regulator and isolator are working properly.

Let us know what you find so we can go from there in tracking down issues.

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Re: best way to find a faulty regulator or isolator

Reply #2 – January 16, 2014, 05:59:11 pm

I will save this and let you know what I find when I revisit the ol girl. It's only a few feet out the back door but I'm just not ready for that with all else I've got going on in other directions. I will let you know for sure once I get back out there. I'll print your info and take it out and follow to the tee.

Thanks

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Re: best way to find a faulty regulator or isolator

Reply #3 – January 18, 2014, 01:45:40 pm

I posted under Trik L Start about what I found today while testing as you recommended and the dates / codes on all 3 8D batteries.

Here's what I found with the test above,

Not running and not plugged into shore....just setting. I checked both outside posts. Both were at 12.64
I started the engine and let it run to warm slightly, then adjusted the rpm to 1200 and let it run there to smooth out. When I tested the two outer posts they were at 14.14. When I then tested the center post it read 15.01

About 3 months ago I installed a new from AIS exact as old and was correct alternator. Hope you don't suggest that it's bad. I've had better visible gage readings with that new part installed then we've ever had before with the old burnt out one. In my opinion, the isolator, regulator and two tiny electric parts mounted to the same 10" x 12" steel plate all look pretty nasty with corrosion etc. Maybe looks don't matter and they all are good.

Your thoughts and or advice Brett?

Thank you as always.

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Re: best way to find a faulty regulator or isolator

Reply #4 – January 18, 2014, 03:49:00 pm

Readings are perfect. 

Alternator and isolator working just fine.

Brett

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Re: best way to find a faulty regulator or isolator

Reply #5 – January 18, 2014, 06:57:43 pm

Oh My GOSH!! That's GREAT news!!

Thanks Brett

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