Battery Isolater with a Yandina combiner or in place of

[Tom Lins]

I hope I am not going to start a flame session but I have to ask for opinions on this.

First some background:
When we first bought the current GMC in 2017 when we started home we had several issues
A dead alternator, a iffy battery (due to age), a battery isolater that was open going to the chassis battery.
While sitting in a campground I changed the alternator only to discover the isolater was open to the chassis battery.
I replaced the isolater also.
About 2 years ago while we had the coach a Sirums, Jeff had to replace the isolater again because it was open to the chassis battery.
Right now I am reading almost 20 volts on the center post of the isolater and 11.9 on the chassis battery.

My question is can I just eliminate the isolater by putting the combiner in place of it and taking the lead from the alternator and wiring it directly
to the chassis battery.
Or am I overlooking something.

--
Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
http://www.bdub.net/tomlins/

 

[RF_Burns]

Tom,
You can eliminate the isolator and wire the alternator output directly to the chassis battery as you described, then install a battery combiner in
place of the isolator.

But I would be concerned as to why the new isolator failed after 2 years. An isolator is just 2 high current diodes so pretty simple stuff. Was it
rated at 90Amps or more? Some offshore stuff has some poor soldering jobs, so I'm thinking that's the cause for the failure.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[Larry Davick]

20 volts? That suggests to me that somehow the two battery banks are wired in series, not parallel.

I have a yandina as well as the combiner and it works very well.

Larry Davick
1976 Palm Beach

>
> I hope I am not going to start a flame session but I have to ask for opinions on this.
>
> First some background:
> When we first bought the current GMC in 2017 when we started home we had several issues
> A dead alternator, a iffy battery (due to age), a battery isolater that was open going to the chassis battery.
> While sitting in a campground I changed the alternator only to discover the isolater was open to the chassis battery.
> I replaced the isolater also.
> About 2 years ago while we had the coach a Sirums, Jeff had to replace the isolater again because it was open to the chassis battery.
> Right now I am reading almost 20 volts on the center post of the isolater and 11.9 on the chassis battery.
>
> My question is can I just eliminate the isolater by putting the combiner in place of it and taking the lead from the alternator and wiring it directly
> to the chassis battery.
> Or am I overlooking something.
>
>
> --
> Tom Lins
> St Augustine, FL
> 77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
> Manuals on DVD
> YOUTUBE Channel: GMC Dealer Training Tapes
> http://www.bdub.net/tomlins/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:

 

[RF_Burns]

I should add that removing the isolator in favour of the combiner will also eliminate the higher voltage available to the dash AC fan. So you will
notice Hi is quite as Hi as it used to be!.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[Ken B]

I am with Bruce on this. I would be worried about why you are blowing isolators. I am wondering if you are installing insolators that are too small.


The next thing I can think of is you have an intermittent open connection on the reference voltage line at the alternator. I had that once and it was
a simple problem that the connector at the alternator lost tension. I squeezed it a little with pliers and never had that problem again.

I only saw the problem because I occasionally monitor the charging voltage whenever I am driving. My suggestion is you do this in the future whatever
isolator replacement option you choose.

Here are a few cheap meters that plug in to the cigarette lighter receptical:

https://usa.banggood.com/4in1-3_1A-Dual-USB-Car-Charger-Adapter-Socket-With-LED-Tester-Voltmeter-p-997029.html?cur_warehouse=USA&ID=233&rmmds=search

I bought 10 of the following one time and gave them away to people:

https://www.aliexpress.com/item/1763220059.html?spm=a2g0o.productlist.0.0.4dfe23d9XWVcOe&algo_pvid=9102605d-493f-4964-9b4a-2773bc150cd5&algo_exp_id=9102605d-493f-4964-9b4a-2773bc150cd5-9

https://www.ebay.com/itm/373602274312?hash=item56fc6e4c08:g:tDAAAOSwIHVgnIcx
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[john r. lebetski]

120A isolator and Yandina combiner across the 2 outer terminal and ground. Proven and works automatically like belt and suspenders.
Now do you have an 80A 27SI alternator or something larger? That gives a 40A headroom. Curious why you have isolator problems as no moving parts.
Has someone “upgraded” to heavier wiring? The original wiring was designed for Voltage drop at high demand to act as a “cushion” in the
circuit. You could have had multiple bad batteries where the impefance drops due to a bad cell and overloads charging system.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Jim Hupy]

I would be suspicious of an alternator going unregulated and pushing the
voltage high enough to damage the isolator.
Or, a crossover voltage from a 120 volt power inverter that
inadvertently got cross wired into the 12 volt DC system.
Those isolators are very robust devices if they are sized correctly
for the amperages invovled..
Jim Hupy
Salem, Oregon

On Sun, Jun 20, 2021, 12:12 PM John R. Lebetski
wrote:

> 120A isolator and Yandina combiner across the 2 outer terminal and ground.
> Proven and works automatically like belt and suspenders.
> Now do you have an 80A 27SI alternator or something larger? That gives a
> 40A headroom. Curious why you have isolator problems as no moving parts.
> Has someone “upgraded” to heavier wiring? The original wiring was
> designed for Voltage drop at high demand to act as a “cushion” in the
> circuit. You could have had multiple bad batteries where the impefance
> drops due to a bad cell and overloads charging system.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>