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Let's talk Combiners [message #369658]

Sun, 15 May 2022 18:12

boybach

Messages: 566
Registered: December 2020
Location: Vancouver Island

Karma: 4

Senior Member

I'm a bit of a pre-schooler in things electrical for sure. I can solder pretty cleanly, observe continuity and determine polarity, but as far as the theory end of stuff goes as it relates to house battery/alternator/isolator/combiner combinations, well- no real idea what to do other than ask here.
This is the situation. I have 2 6v 232AH GC's back in the cubby by the genny. I would like to keep the house batteries and my starter battery up front charged up, obviously. I very rarely if ever plug into a 110 source so my charging will all be from either the genny or from driving. I've thought about getting a cheap Coleman solar trickle maintainer for the house batteries but have held off from getting one because there may be times that the coach will sit for weeks at a time -and I'm afraid of overcharging using it straight out of the box without some sort of controller.

I have a 55 amp converter and afaik my alternator is standard size.

So what will a combiner do for me that the isolator won't?

Thanks

Larry

Larry - Victoria BC - 1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses

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Re: Let's talk Combiners [message #369659 is a reply to message #369658]

Sun, 15 May 2022 19:38

Ken Burton

Messages: 10030
Registered: January 2004
Location: Hebron, Indiana

Karma: 10

Senior Member

First I am biased Against adding a combiner. If you needed one what did your coach do for it's first 40 years without one? How many times have you had a dead engine battery while parked and the house batteries were fully charged? I have replaced 3 combiners in my life on other peoples coaches and never replaced an isolator on any GMC. I do not have one on my coach. In my opinion a combiner is an item in A GMC looking for a non existent problem to fix. I do carry a one dollar combiner in case I ever need it. I have never used it.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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Re: Let's talk Combiners [message #369660 is a reply to message #369658]

Sun, 15 May 2022 19:44

RF_Burns

Messages: 2276
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

I also have a 1977 Ex-Palm Beach.

The benefit of a Combiner over an Isolator is that it allows the house converter to also charge the chassis (engine) battery.

The benefit of the Isolator is that it provides a 0.7 volt higher source to power the dash HVAC fan to a higher speed while on Max. It also is a very simple device (just 2 power diodes). There are no mechanical relays or other electronics in the Isolator. Don't fall for the old wives tale that you can't fully charge your batteries because of the Isolator's voltage drop. The OEM generator had a voltage sense lead on the chassis battery side. Therefore the alternator increases its output voltage to compensate for the Isolator's voltage drop. If your alternator has a 14.3 volt regulator, it will output 15 volts to the Isolator and from the voltage sense wire it will see 14.3 volts to the battery(s).

Many of us have wired a combiner across the isolator to get the best of both worlds. The Isolator will provide charging to both sets of batteries from the engine alternator, and the Combiner will allow the chassis battery to charge from the house converter.

Here is some photos and instructions on installing a Combiner across the Isolator. Note you only need a basic 100Amp Yandia combiner to do this.
http://www.gmcmhphotos.com/photos/frank/p51191-10-minute-combiner-install.html

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

[Updated on: Sun, 15 May 2022 19:45]

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Re: Let's talk Combiners [message #369661 is a reply to message #369658]

Sun, 15 May 2022 19:46

RF_Burns

Messages: 2276
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

Forgot to add the link, so here is the link for the email users.

http://www.gmcmhphotos.com/photos/frank/p51191-10-minute-combiner-install.html

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Re: Let's talk Combiners [message #369663 is a reply to message #369658]

Sun, 15 May 2022 20:38

lqqkatjon

Messages: 2324
Registered: October 2010
Location: St. Cloud, MN

Karma: 5

Senior Member

Do you need a combiner??? The answer is No.

Do you want a combiner. My opinion is YES. Simple inexpensive device will save your starting battery. Most gmc’s have some parasitic draw that you can find, sometimes it is not worth finding.

I always say- battery cutoff switch is a good thing. Also a combiner so when your coach is plugged in, your starter battery gets a good charge.

Now the key item is you should have a 3 stage smart charger/converter for the house. That is 1st thing to get rid of buzz box and upgrade there before worrying about a combiner.

I have installed numerous victron combiners. I prefer these and still keep the blue isolator in place and just wire these to the isolator. Belts and suspenders, still easy to test with a meter. And talk someone over the phone for basic troubleshooting of charging/alternator.

The yardina that was popular looks like a ball of too many wires. Fine if you have some electrical knowledge.. hard to even know what it is or where wires go if an owner is electrical challenged.

$50. Is a good item to install.

https://www.amazon.com/Victron-Intelligent-Battery-Combiner-Cyrix-ct/dp/B071Y7C9MM/ref=mp_s_a_1_4?crid=2RMFP635JIWF6&keywords=victron+combiner& ;qid=1652663851&sprefix=victron+com%2Caps%2C109&sr=8-4

Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/

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Re: Let's talk Combiners [message #369664 is a reply to message #369658]

Sun, 15 May 2022 21:36

boybach

Messages: 566
Registered: December 2020
Location: Vancouver Island

Karma: 4

Senior Member

Well thanks for all the responses, really cleared up my understanding of the combiner's function.

I have big ol shutoff switches both up front and in back in the house alcove. I usually switch off the starter battery any time I'm parked up and over winter this has worked just fine. My starter battery still has plenty of oomph so I'm not really concerned with or apparently in need of a combiner.

My main issue is keeping my new house system batteries charged up. What do you guys think about adding a small solar trickle maintainer/charger and just hooking it up to the house bank directly? Would I need some way of limiting the output to prevent overcharging if I left it in place for an extended period, say a month or so in the middle of summer?

I never plug in to 110 BTW. Coach is stored too far from power and tend to dry camp too.

thanks

Larry

[Updated on: Sun, 15 May 2022 21:38]

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Re: Let's talk Combiners [message #369674 is a reply to message #369664]

Mon, 16 May 2022 10:42

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Larry,

The leakage loss of modern Lead Acid batteries is very low as you have discovered by switching out the main engine starting battery. For many of the yachts that I have worked on, I have installed a 5~10 watt panel as a keep-alive and I have never had a reported problem. You can use a panel that size to charge a bank indefinitely with no damage and =>Maybe<= a small water loss. Were my coach not at home, I would find a panel that size and put it in a south facing window and steadfastly refuse to worry about it from then on.

I have never installed a Victron combiner. I have installed and replaced a number of both Yandina and Blue Sea (a Yandina knock-off) combiners. As Jon said, the 100 amp version has a lot of wires to deal with and all of these have internal contacts. The only time I have had to replace a diode version combiner was when the owner attached a battery with the polarity reversed. The combiner was not the only damage in that event.

A singular reason I am not in favor of combiners is that they can mask another problem that could be revealed by the common instruments. This is not a common mode failure, but the event was troublesome none the less.

Do you own a meter of any kind?? If no, go get one. It almost does not matter how cheap it is as long as it has a 20 volt DC scale. If it is new and in the package, open the package and take the battery out. Write the month/year on the battery and tape it to the outside of the package. When the battery is 5 years old, get an new one to tape on there. The idea is if it is needed and you don't know how to use it, you may be able to find or call some one that does. My personal record for this is about 300 miles of separation and communication was only e-mail. The 60 mile time by marine VHF was somewhat more difficult, but it was possible.

Matt

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

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Re: Let's talk Combiners [message #369675 is a reply to message #369658]

Mon, 16 May 2022 11:01

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

A Yandina 100 is $70. The trick is to NOT remove the isolator. The combiner gets installed to the 2 outer isolator terminals (B1/B2) and neatly mounts to the aluminum firewall panel and gets a ground wire. Dress the combiner wires with a cable tie (do not cut wires) and done. The other wires are for options you don’t need such as forced combine and remote indicator light so just tape them neatly aside. You retain all the GM engineering goodness and add a modern feature that wasn’t around in the 70s. You won’t have to ever mess with a jumper or forget it’s there and ruin all your batteries by deep killing them. I’m a purist, but this is such a simple way to modernize the electrical system in a non invasive manner that is reversible in 2 mins if you want to remove it.

John Lebetski
Woodstock, IL
77 Eleganza II

[Updated on: Mon, 16 May 2022 12:22]

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Re: Let's talk Combiners [message #369681 is a reply to message #369674]

Mon, 16 May 2022 16:38

boybach

Messages: 566
Registered: December 2020
Location: Vancouver Island

Karma: 4

Senior Member

Matt Colie wrote on Mon, 16 May 2022 08:42

Larry,

The leakage loss of modern Lead Acid batteries is very low as you have discovered by switching out the main engine starting battery. For many of the yachts that I have worked on, I have installed a 5~10 watt panel as a keep-alive and I have never had a reported problem. You can use a panel that size to charge a bank indefinitely with no damage and =>Maybe<= a small water loss. Were my coach not at home, I would find a panel that size and put it in a south facing window and steadfastly refuse to worry about it from then on.

Matt

Thanks Matt, I'll pick up a small panel as you suggest. I use a master switch on both batteries in my boat and that seems to work just fine, no problem firing up the engine after winter.

Larry

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Re: Let's talk Combiners [message #369682 is a reply to message #369658]

Mon, 16 May 2022 20:42

Carl S.

Messages: 4186
Registered: January 2009
Location: Tucson, AZ.

Karma: 13

Senior Member

My coach came to me with the isolator replaced with a combiner. In 13 years I never had a problem with it. I have 195 watts of solar on the roof and it keeps both sets of batteries charged at all times, even when not plugged in.

The only thing a combiner will do that your current set-up is not doing, would be to charge the chassis battery from your converter when your coach is plugged in. If you never plug your coach in to shore power, a combiner would be useless to you.

I have since converted my coach to LiFePo4 batteries which required the installation of a LI-BIM which acts as a combiner, but shuts off the charge to the house batteries intermittently to save the alternator from burning itself up trying to pump as much current into the Lithium batteries as they will take.

Carl Stouffer '75 ex Palm Beach Tucson, AZ. Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member

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Re: Let's talk Combiners [message #369823 is a reply to message #369658]

Tue, 31 May 2022 18:06

Scott Nutter

Messages: 782
Registered: January 2015
Location: Houston/San Diego

Karma: 4

Senior Member

I have noticed a few GMC’s where the battery isolator has been remover and replaced with the “Blue Sea SI automatic charging relay”. I’m by no means a expert on the combiners vs isolator debate. But on paper, the Blue Sea SI looks pretty good. It automatically combines both batteries while charging (either with external power or alternator). And isolates the battery banks while discharging. Isn’t that what we’re looking for? Sounds more like a automatic Perko switch. Hopefully some of our electrical gurus will chime in..
Scott.

Scott Nutter 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI Houston, Texas

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Re: Let's talk Combiners [message #369829 is a reply to message #369658]

Wed, 01 June 2022 18:06

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

Yes a voltage controled relay. Relays have contacts that can pit and fail. Diodes sized larger than the alternator capacity should last a lifetime. Again, removing the isolator you will lose some HI blower speed and will have replaced the solid state device with a life cycle limited device. I still say best to keep the isolator and add a combiner to keep all the benefits. That’s what I did

John Lebetski
Woodstock, IL
77 Eleganza II

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