Isolater vs Alternator

[Ken H.]

Rob,

Looking at the Catalog page, it appears that she no longer uses external
relays for any of her combiners. I don't see that as a problem.
Apparently no longer sells the C-135's either. I DO see there that she's
got refurbished (with FULL warranty) C-160's for $99. That's what I'd buy
('cause I'm CHEEP & don't see the down side with a full warranty).

Now I know why I bought several solenoid relays cheap from her some time
back -- probably because she was phasing them out of combiners.

Ken H.

On Sun, Dec 3, 2017 at 10:01 AM, Rob Mueller
wrote:

> Ken,
>
> I clicked on the C-160 and this link opened:
>
> http://www.yandina.com/c160Info.htm
>
> It doesn't say anything about a large external relay?
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
> Henderson
> Sent: Sunday, December 3, 2017 8:57 AM
> To: GMC Mail List
> Subject: Re: [GMCnet] Isolater vs Alternator
>
> Yes. IIRC, the C-160 uses a large external solenoid relay rather than the
> internal one in my C-135.
>
> Ken H.
>
>
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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>

 

[robert mueller]

Ken,

Thanks, I just ordered one.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken Henderson
Sent: Sunday, December 3, 2017 9:30 AM
To: GMC Mail List
Subject: Re: [GMCnet] Isolater vs Alternator

Rob,

Looking at the Catalog page, it appears that she no longer uses external
relays for any of her combiners. I don't see that as a problem.
Apparently no longer sells the C-135's either. I DO see there that she's
got refurbished (with FULL warranty) C-160's for $99. That's what I'd buy
('cause I'm CHEEP & don't see the down side with a full warranty).

Now I know why I bought several solenoid relays cheap from her some time
back -- probably because she was phasing them out of combiners.

Ken H.

 

[john phillips]

Does a combiner tie both battery sets together when it starts to charge? If
so how do you avoid using the charged battery to charge the discharged
battery?
I would think the isolator even if you went to 400 amps would be a better
deal as long as you use a remote sense alternator. There is a 400 amp full
wave bride on eBay for less than $30 and the $150 amp is less than $10.
What am I missing about a combiner?

> Wow. Doom and gloom on isolators.
>
> My OEM isolator and my 100 amp dual pulley alternator have co-existed for
> 13 years. I put a lot of load on them as I seldom plug in anywhere when I
> travel. So during the day my alternator and isolator have to recover the
> discharged golf cart batteries.
>
> I have been involved with the replacement of 3 combiners and 1 isolator on
> GMCs. None of which were on my coach. The isolator that broke was rusted
> so badly that I twisted off a stud trying to loosen the rusted nut. Had I
> left it alone and not tried to clean the connections it probably would
> still be running today. I have the bad isolator and someday I'll open it
> up to see if the stud can be replaced. It was and is still good
> electrically. That is more than I can say about the three bad combiners I
> worked on. Two of the bad combiners were on Dan's coach. He ended up
> carrying a spare in case it failed again.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>

--

*John Phillips*

 

[d c *mac* macdonald]

Addition of a combiner enables independent charging of both chassis (engine) AND house batteries from the AC power supply (so-called converter). Unlike the isolator, which uses diodes to prevent back charging and has an approximately .7 Volt drop, the combiner uses circuitry to sense which battery is being charged and will direct charging current from either vehicle alternator or shore powered "converter" to the battery with the lowest charge.

At least that is MY understanding of it!

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist on behalf of John Phillips
Sent: Sunday, December 3, 2017 16:39
To: gmclist
Subject: Re: [GMCnet] Isolater vs Alternator

Does a combiner tie both battery sets together when it starts to charge? If
so how do you avoid using the charged battery to charge the discharged
battery?
I would think the isolator even if you went to 400 amps would be a better
deal as long as you use a remote sense alternator. There is a 400 amp full
wave bride on eBay for less than $30 and the $150 amp is less than $10.
What am I missing about a combiner?

> Wow. Doom and gloom on isolators.
>
> My OEM isolator and my 100 amp dual pulley alternator have co-existed for
> 13 years. I put a lot of load on them as I seldom plug in anywhere when I
> travel. So during the day my alternator and isolator have to recover the
> discharged golf cart batteries.
>
> I have been involved with the replacement of 3 combiners and 1 isolator on
> GMCs. None of which were on my coach. The isolator that broke was rusted
> so badly that I twisted off a stud trying to loosen the rusted nut. Had I
> left it alone and not tried to clean the connections it probably would
> still be running today. I have the bad isolator and someday I'll open it
> up to see if the stud can be replaced. It was and is still good
> electrically. That is more than I can say about the three bad combiners I
> worked on. Two of the bad combiners were on Dan's coach. He ended up
> carrying a spare in case it failed again.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>

--

*John Phillips*
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[Matt Colie]

> Does a combiner tie both battery sets together when it starts to charge? If
> so how do you avoid using the charged battery to charge the discharged battery?
> I would think the isolator even if you went to 400 amps would be a better deal as long as you use a remote sense alternator. There is a 400 amp
> fullwave bride on eBay for less than $30 and the $150 amp is less than $10.
> What am I missing about a combiner?
> --
> *John Phillips*

John,

Nothing.

But you still need to buy a heat sink for either of those bridges.

I had a VHF service call from a vessel that had a Volvo engine with an electric run solenoid on the injection pump. Overnight, the house bank
crashed.
Problem:
Could not start the generator on the house bank.
The main engine would start just fine. And run for ~30 seconds and shut down. Now he was getting very nervous because the main engine battery was
getting weak....
I had recently redone the system with a combiner by the owner's choice.
I had him do a number of checks with the little red Hazard Fright meter I had left with him. When he said that he measured the house bank at 8.5, I
had him disconnect the bank at the house bank junction. (Bank was 2 ea 4D one of which was smoking - literally and fuse between them was gone.)
Then he could start the main engine and have it stay and make for the mainland to get at least one new battery.

By all rights, and according to Anne-Marie, the combiner should have dropped out before the main engine shut down. I think the hysteresis in the
system was actually a good thing.

This story goes on to a happy (but not inexpensive) ending.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Ken H.]

John,

Three things I like about combiners vs isolators:

1. The alternator sense line is always connected to the chassis battery.

2. The combiner is bidirectional so that if either the alternator or the
converter is producing adequate voltage, both batteries will be charged.
Without my having to remember to connect Ken B's $1 combiner (jumper wire).

3. If there is a combiner failure, since #1 above is true, it does not
result in the 28+ VDC I've seen on the house circuits several times after
combiner diodes opened.

Ken H.

On Sun, Dec 3, 2017 at 5:39 PM, John Phillips
wrote:

> Does a combiner tie both battery sets together when it starts to charge? If
> so how do you avoid using the charged battery to charge the discharged
> battery?
> I would think the isolator even if you went to 400 amps would be a better
> deal as long as you use a remote sense alternator. There is a 400 amp full
> wave bride on eBay for less than $30 and the $150 amp is less than $10.
> What am I missing about a combiner?
>
>

 

[Ken B]

It is my understanding that the Yandina combiner has a 30 second or so delay before combining (putting the batteries
in parallel). If the combined load is too high drawing the system voltage below the combine point (usually 13.2
or 13.3 volts) I "think" there is also a delay before uncombining. This was delay design was to prevent or reduce
chatter of off and on and off again repeatedly. It also allows the alternator to put an initial charge
into the single battery that was just used for starting and to reduce the rate of charge somewhat to it
before bringing a second battery online. It usually works OK but if the one coming online is discharged
enough or shorted you will still experience the cycling and brief drain described.

I do not know if this is true on other brands of combiners. Combiners are fine when they work as designed and
they have a few added features. They also introduce a few new modes of possible failure.




--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Rdenney]

A combiner only combines when there is charging voltage present. Current
goes from higher voltage to lower voltage, so it always goes from the
charging source to the batteries, and not from one battery to the other.
The current will divide itself to be drawn more to the battery at a lower
charge state.

The problem of batteries killing each other happens when there is no
charging source active, and current flows from the higher battery to the
lower one. If the lower battery can't take a charge, both will end up dead.
But a combiner de-combines at voltages below charging voltage (13.1 volts).

http://www.gmceast.com/technical/Denney_GMC_Electrical_Sys.pdf

Rick "fulfilling requirements automatically" Denney

On Sun, Dec 3, 2017 at 3:40 PM John Phillips
wrote:

> Does a combiner tie both battery sets together when it starts to charge? If
> so how do you avoid using the charged battery to charge the discharged
> battery?
> I would think the isolator even if you went to 400 amps would be a better
> deal as long as you use a remote sense alternator. There is a 400 amp full
> wave bride on eBay for less than $30 and the $150 amp is less than $10.
> What am I missing about a combiner?
>
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com