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Topic: Bad Isolator? (Read 3040 times) previous topic - next topic

Re: Bad Isolator?

Reply #25
My approach to diode isolator and boost solenoid use is as "KISS" as it can get. I do not use them, and while they are still mounted in my coach, they are not connected.

I have one three 8D battery bank, which provides 12 volt power to coach circuits and to chassis circuits. These  three 8D batteries are deep cycle batteries which will provide more cold cranking amps than the three Red Top start batteries Foretravel installed to power the chassis circuits. For this to be successful, you must carefully manage the state of charge of your batteries. I keep my batteries charged with solar panels, and have installed an amphour meter on each battery.

If you use solar panels and your batteries are fully charged each day, give my approach a try, it works very well for me.








Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Bad Isolator?

Reply #26
My approach to diode isolator and boost solenoid use is as "KISS" as it can get. I do not use them, and while they are still mounted in my coach, they are not connected.

I have one three 8D battery bank, which provides 12 volt power to coach circuits and to chassis circuits. These  three 8D batteries are deep cycle batteries which will provide more cold cranking amps than the three Red Top start batteries Foretravel installed to power the chassis circuits. For this to be successful, you must carefully manage the state of charge of your batteries. I keep my batteries charged with solar panels, and have installed an amphour meter on each battery.

If you use solar panels and your batteries are fully charged each day, give my approach a try, it works very well for me.











And if a worst case sceneario hits, all batteries too dead to start the generator and the sun down, you still have the Suzuki and a set of jumper cables.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: Bad Isolator?

Reply #27
What would happen if I connect a "Red" positive cable from Alternator connection post on the Battery Isolator directly on to Engine Battery "Positive" terminal while keeping everything in original "OEM" set up?

I read through 3 post vs 4 post Isolator discussions (Thank you for great information!) perhaps it went over my head a bit ... I was thinking to replace my 20 year old 4 post Battery Isolator with a 3 post. Currently I have all new 4x6v Golf Cart battery set up for my house batteries and once they are charged over night they have almost 500amph. More than good enough to run the residential Fridge and a floor fan all day (that's how i travel to west cost last year. Once i was in CO there was no need for Gen to run the over head AC. So essentially I have two batteries one for Engine & "one" for House, what would be the advantage of having a 4 post Isolator. I am thinking 3 post is all it needs no?

My problem is there is a .60v drop to engine battery. I discovered it by using a voltmeter on the Isolator. While Engine running, in idling mode (i was alone & could not get some one to rev it up to 2k rpm) on Isolator ALT post reads 12.40~12.60 (i know my Alternator is suspect too) House Batter Post & House Battery readings are same, same as ALT post reading. So that side is healthy. But the Eng Battery post side is 11.70~11.90 never 12v. It does go up to 12v when booster switch is turned on.

Has anyone done Brett Wolf's "KISS" method, if so what brand/ kind of switch would i use? 
I rather charge my Engine battery when driving and leave the house battery charging to shore and Generator power. But I will still like to keep booster capability in place.

Thank you for your help!
AL
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)

Re: Bad Isolator?

Reply #28
Al,

Be aware that it is NORMAL to have .6-.7 VDC drop across the battery isolator.  SO, alternator should put out 14.7-15.0 VDC (measure at B+ terminal of alternator or center lug of isolator.

The two outer lugs (to the battery banks should each read around 14 VDC (that .6-.7 VDC lower than the center lug).

Now, if one outer lug reads substantially lower, then the other, THAT is a problem (assuming that battery bank is good and not deeply discharged).
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Bad Isolator?

Reply #29
Good day,
Thinking I would like some advice to the following question. Looking at the attached picture can anyone advise by looking at the isolator which side is going to the start batteries and which side is going to the house batteries. The isolator does not have any labeling. I am installing a new cole hersee 200 amp continuous isolator as well a new cole hersee 200 amp solenoid.  ALSO do these cables look ok or would I be better advised to replace the orange cables shown
My coach is stored for the winter so I can not crawl in to check the connections...
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Bad Isolator?

Reply #30
Doesn't matter on the house and start whwhich outside terminal they go on. The center cbl is from the alternator. The cable definitely need a good cleaning, aside from that no way other than a voltage drop test under a load.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Bad Isolator?

Reply #31
Compare the little white labels on the cables to your schematic and you can quickly see which goes to which bank. Your cable lugs probably just need cleaning. The isolator panel is in a terrible location so frequently needs attention so everything is trouble free. Take a phone photo before taking anything off so it goes back on correctly. The previous owner of ours had mixed everything up.

Lots of ways to clean up cable lugs. I've even used a hand held HF sandblaster with sand, beads or shells.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Bad Isolator?

Reply #32
Other way to identify "which is which" is with a digital voltmeter.  Very unlikely unless you have a battery combiner ON or boost switch ON for voltage to be exactly the same at each battery bank.  Compare readings at the lugs with that at the batteries themselves.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Bad Isolator?

Reply #33
I keep a small roll of emery cloth to polish cable ends.  You can also use colored ty-raps to mark each cable & it's connection.  After cleaning and re-connecting put a coating of dielectric grease.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell