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Isolator problem

Three(ish) years ago. I installed a new isolator. It's a Sterling zero loss two batt marine rated model.
Events were that we arrived at our camp site after a four hour drive. We are plugged in. This morning we were awakened by a very loud alternating on and off buzzing. It was coming from the Sterling isolator. No led's were on. As they are right next to the iso, I disconnect the start batt. The buzzing stopped. Got out the multimeter and batteries were at 13.4V. Next thing I did was to turn on the starter key and reconnect the isolator. No buzzing. And the leds were as normal. Turned of the 'ignition' key and the buzzing commenced.

Maybe a bad isolator?

The house batteries are on the charger and were on float. I disconnected the pos cable and put the start batt on a charger just to make sure. After the charge cycle, I will hook everything back up and report what happens.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #1 –
Give Justin at Bay Marine a call to help diagnose this.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Isolator problem

Reply #2 –
FWIW your Sterling Zero Volt Drop battery isolator uses a relay to separate the batteries.  So you should listen closely the next time it malfunctions and ask yourself if you are hearing an "AC Hum" or mechanical relay chatter.  If you decide it's the latter, taking the Sterling out of circuit would be a good idea.  If the former, something else handling DC power from the AC mains is failing.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Isolator problem

Reply #3 –
Tried calling west marine. They are all working from home and the mothership in the UK is closed due to covid.

Even though the batteries were at 13.4V.
After having them on trickle charge all day. I connected the start batteries again. The iso unit didn't make a peep.

I will be at gracerace's (Chris White's) house on Monday. I'll touch base with him on this issue as well.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #4 –
Quote from: bigdog –

Even though the batteries were at 13.4V.
After having them on trickle charge all day. I connected the start batteries again. The iso unit didn't make a peep.


It's quite possible that, unless you have a loose connection somewhere, you found a bug in that 1,000 lines of code.  If so, good luck reproducing the failure.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Isolator problem

Reply #5 –
I am going  to post again about the industry wide use of battery bank  combiners replacing battery bank isolators.,.,

My experience is that one occurrence of not charging the chassis batteries correctly permanently lowers their capacity.

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Isolator problem

Reply #6 –
I think I have a bad start battery(s) or at least a dead cell. As a month ago the batteries passed a load test with flying colors. They are 5 years old and have been rundown 2-3 times from phantom draws during storage.

I noticed a new light on the sterling today after reconnecting the main neg cable on the start battery. The sterling was showing some feedback. Which according to the manual is indicative of a weak bank being charged by a second bank, But not to the point of the relay doing it's isolation duty.
This was after running a 10 amp charger to the start batteries and it showing full charge. The cold engine was def hard to start. Had to use the boost.

So off to Pendleton this week to pick up 3 new redtops.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #7 –
May I respectfully suggest adding a auto combiner instead of a combiner?

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Isolator problem

Reply #8 –
That depends Bob. As it's seems the issue is a battery not the isolator. Yet. If the isolator is wonky. I want to go simple next time.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #9 –
I killed 2 sets of redtops before the auto combiner install.

Once totally discharged batteries are never the same in my experience. 

If you have power into the coach it's foolproof
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Isolator problem

Reply #10 –
Mine were dead because of phantom loads. I usually disconnect the start batteries when it sits for a long time now. Where I haven't in the past.
My old Xantrex 2500 only charges the house bank unless the boost switch is left on. But as I have heard. FT recommends a max of 24 hours of boost switch activation while charging.

In the meantime. I'm just going to replace the old start batteries with new ones and see what the isolator does.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #11 –
The boost draws 3 amps and gets physically hot.  The auto connect is magnetic latching and consumes zero power after engaged.

Every new coach has a combiner as far as I know.  Close to $700 to kill another set of redtops as you well know.

Got tired  of non 100% reliable.  Where we are we have to have this run in a emergency.  Not an option
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Isolator problem

Reply #12 –
Quote from: bigdog –
Mine were dead because of phantom loads. I usually disconnect the start batteries when it sits for a long time now. Where I haven't in the past.
My old Xantrex 2500 only charges the house bank unless the boost switch is left on. But as I have heard. FT recommends a max of 24 hours of boost switch activation while charging.

In the meantime. I'm just going to replace the old start batteries with new ones and see what the isolator does.

I'm betting that your isolator goes back to normal.  I like the idea of a battery combiner but I like the idea of my solid state isolator better.  4 or 5 down on my to do list is a second PD 9260 battery charger dedicated to the chassis battery because I like the idea of having 120A total boost from my generator set.  Why?  Because on a very cold night after a long day I did leave the headlights on and the furnace did run down the house batteries down leaving me with the gen set's dedicated battery.  On our previous rig.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Isolator problem

Reply #13 –
Quote from: Old Toolmaker –
I'm betting that your isolator goes back to normal. 
That's my thought as well. What threw me off was having each of the three batteries load testing within spec. But when I was in CDA visiting Gracerace. He mentioned that he had the same battery issue as me. Load test fine, But checked each individual cell via hydrometer. And a cell was bad.
And that is likely why every now and then. I get a generic low voltage fault code on my VMSpc. Even the guys at a large Cummins shop in Boise said that particular code number usually happens from a battery issue.
We will see.
I'll of course report back as to how it turns out.
Jerry & Nona and Kimeru the cat that thinks she's a dog
1998 36' WTFE U320  #5314 Motorcade #17711
USAF 1975-1995
2019 Subaru Crosstrek 'toad'
2003 Subaru Legacy touring car
jerry Fincher | Flickr

Re: Isolator problem

Reply #14 –
Isolator does not work on shore power.  Only divides up alternator.  Hence the combiners invention
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4