GMCforum: GMCnet » Battery bank wiring for a 73

Home » Public Forums » GMCnet » Battery bank wiring for a 73 (would like to add more batteries)

Show: Today's Messages :: Polls :: Message Navigator

Battery bank wiring for a 73 [message #359110]

Wed, 30 September 2020 10:56

lqqkatjon

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

Karma: 5

Senior Member

I am assisting with some work on a pretty stock 73 GMC sequia. I had the owner go out and buy a ragusa sliding battery tray, because when we originally took a quick look at it, I noticed there was no rear battery, and he was complaining the interior systems were not working, and his gen light was on. I just figured someone had removed the house batteries.

now that I was able to spend a weekend with the coach, I have figured out(or remembered) that 73 has the house battery up front, and in the back they just have a battery for the onan.

So I have everything now back hooked up properly- stock. He had 2 new batteries for the front, a nice starting battery and a nice 12v deep cycle marine/RV for the house. Isolator is working and I installed a combiner.

so the question is, we have a nice ragusa sliding battery tray by the onan, now. and think it should be filled up with batteries.

How would one suggest the best way to do that? just install it with a shut off/switch. the question I am getting at, is as I understand we would not want to tie it in parallel with the 12v marine/deep cycle up front and make it just 1 larger battery bank because they might drain each other or melt down in a cell failure?

how have others done theirs?

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

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359114 is a reply to message #359110]

Wed, 30 September 2020 17:39

lotsofspareparts

Messages: 726
Registered: May 2014
Location: Arlington, WA

Karma: -9

Senior Member

I can't imagine it would be to much different than a boat.

Sometimes we have house batteries on opposite ends of the boat, tied together by 2/O cable typically.

Nothing in the GMC MH has the amp draw that something like a bow thruster in a boat would have, so you should be able to get by with a 4awg positive cable and tie the negative directly to the frame.

Jared

Jared & Tina Lazaron + 14yr old Daughter..... 77 Eleganza II "Recherché"..... 73 Canyon Lands 230 "Elephant"

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359138 is a reply to message #359110]

Thu, 01 October 2020 12:41

Matt Colie

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

Karma: 7

Senior Member

lqqkatjon wrote on Wed, 30 September 2020 11:56

I am assisting with some work on a pretty stock 73 GMC sequia. I had the owner go out and buy a ragusa sliding battery tray, because when we originally took a quick look at it, I noticed there was no rear battery, and he was complaining the interior systems were not working, and his gen light was on. I just figured someone had removed the house batteries.

now that I was able to spend a weekend with the coach, I have figured out(or remembered) that 73 has the house battery up front, and in the back they just have a battery for the onan.

So I have everything now back hooked up properly- stock. He had 2 new batteries for the front, a nice starting battery and a nice 12v deep cycle marine/RV for the house. Isolator is working and I installed a combiner.

so the question is, we have a nice ragusa sliding battery tray by the onan, now. and think it should be filled up with batteries.

How would one suggest the best way to do that? just install it with a shut off/switch. the question I am getting at, is as I understand we would not want to tie it in parallel with the 12v marine/deep cycle up front and make it just 1 larger battery bank because they might drain each other or melt down in a cell failure?

how have others done theirs?

Jon,

I did not have any choice as the 23s don't have the space near the APU for batteries. If you do as you have described, and you do little else, he will not get in trouble right away. There is a distinct problem with the original wiring. There is only a #10SAE cable to the rear. That will serve as a sort of as a current limiter to prevent any likely disaster. It will also limit the charge rate av available to to recover the house bank.
There was a battery in the rear to crank the APU and do nothing else, but you can connect from there to the DC distribution panel that is nearby and use the new house bank to crank as well. The thing that will not work is the battery boost will be just about worthless.
Having a pair of GC2s in the front is a monumental pain.
I bet this didn't answer all your questions, but I lost both may desktop and my laptop computers yesterday and I am working on recovery. If I don't get back to you right away, please be patient.

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

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359139 is a reply to message #359110]

Thu, 01 October 2020 13:24

JohnL455

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

Karma: 12

Senior Member

Put a Blue Sea A/B mains switch on the house batteries. Only one gets used at a time for house power. No hard parallel. Put a $70 Yandina combiner between the 2 batteries. Then the batteries are always independent and only parallel by #10 wire when charge Voltage is present. If one gets low boondocking, switch to other. But both alway charge from Alternator via isolator or 125 to 12VDC convertor.

John Lebetski
Woodstock, IL
77 Eleganza II

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359142 is a reply to message #359110]

Thu, 01 October 2020 16:50

Dennis S

Messages: 3046
Registered: November 2005

Karma: 2

Senior Member

Jon

This link is to GMC East States tech article by Rick D
He shows 1973 coach set up with combiners.

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

lqqkatjon wrote on Wed, 30 September 2020 10:56

I am assisting with some work on a pretty stock 73 GMC sequia. I had the owner go out and buy a ragusa sliding battery tray, because when we originally took a quick look at it, I noticed there was no rear battery, and he was complaining the interior systems were not working, and his gen light was on. I just figured someone had removed the house batteries.

now that I was able to spend a weekend with the coach, I have figured out(or remembered) that 73 has the house battery up front, and in the back they just have a battery for the onan.

So I have everything now back hooked up properly- stock. He had 2 new batteries for the front, a nice starting battery and a nice 12v deep cycle marine/RV for the house. Isolator is working and I installed a combiner.

so the question is, we have a nice ragusa sliding battery tray by the onan, now. and think it should be filled up with batteries.

How would one suggest the best way to do that? just install it with a shut off/switch. the question I am getting at, is as I understand we would not want to tie it in parallel with the 12v marine/deep cycle up front and make it just 1 larger battery bank because they might drain each other or melt down in a cell failure?

how have others done theirs?

Dennis S
73 Painted Desert 230
Memphis TN Metro

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359302 is a reply to message #359142]

Thu, 08 October 2020 22:30

Husker92592

Messages: 137
Registered: August 2013
Location: Temecula ca

Karma: -4

Senior Member

So I have a question in regards to the 1974 26', I only have a starting battery up front with a generator battery in the back. Not sure about my wiring rats nest back by the Onan but, I am trying to repair that. Anyway. there is a circuit breaker up front as well as one in the back by the Onan inside rear wall. Is it the same for the 26' 1974 that the house batteries are up front? I am in the process of running a new wire all the way front to back with a 2/0 ( to handle existing and additional battery loads and a 1/0 for the battery in the rear and reconnect the Onan.

I know that most things in the coach are still factory so is there a simpleton wiring schematic on the 26'?
thanks

1974 GMC Sequoia 26'

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359314 is a reply to message #359302]

Fri, 09 October 2020 09:07

lqqkatjon

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

Karma: 5

Senior Member

wiring schematics are all on bdub's site.

I cannot really say what your 74 might be, but what you describe is common on most gmc upfit coaches like my 75 palm beach:

Back by the onan, there can be a round circuit breaker. as well as a solenoid. Up front, there should also be a solenoid.

ON those coaches, Starting battery is up by engine, and house batteries by onan. and there are a "boost solenoid" front and back, and a heavy awg wire that goes from front battery, hits a terminal block by the "buzz box/converter" and then back to onan compartment.

the round circuit breaker normally protects the house wiring at 50 amps.

when you press the "boost" button on dash, it engergizes the front solenoid that connects both the starting battery to the heavy awg wire to the rear battery, and engergizes the rear solenoid, that then creats a bypass of that 50 amp circuit breaker to allow more then 50 amps to go to the starting battery to assist in engine cranking.

ONan wires come off the back of the onan drawer, and connect up to the house battery system direct.

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

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359335 is a reply to message #359314]

Fri, 09 October 2020 20:02

Husker92592

Messages: 137
Registered: August 2013
Location: Temecula ca

Karma: -4

Senior Member

to include the starter for the onan? so the house batteries in the back by the onan are the house batteries ( two 6 volt) as well as the starting batteries for the Onan?

So if we wanted more "house" battery capacity where do we add them up front with additional wiring?

Thanks

1974 GMC Sequoia 26'

[Updated on: Fri, 09 October 2020 20:17]

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359350 is a reply to message #359335]

Sat, 10 October 2020 09:48

Matt Colie

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

Karma: 7

Senior Member

Husker92592 wrote on Fri, 09 October 2020 21:02

to include the starter for the onan? so the house batteries in the back by the onan are the house batteries ( two 6 volt) as well as the starting batteries for the Onan?

So if we wanted more "house" battery capacity where do we add them up front with additional wiring?

Thanks

Grant,

It appears that what you have is a '74 set up like the later coaches, but without the heavy conductor and contactors for the start-boost circuit. Except for the less effective boost capability, this is no issue.

There is a problem.....
If you want to increase the jar count in the house bank, it wants to be outside of the living area. (Lead/Acid batteries do not make good company.) There are not many places in a TZE that this could be. I don't think you want to revert to a house bank in the right front corner. It is a bear. The left front corner has your air pump.

What my real $uggestion??
Replace 19th century batteries with LiFePo4. These are expensive and updating the rest of the system will not be cheap either, but you can have enough DC power to run the microwave and anything else. (The roof air will require a HUGE inverter.) Apart from buying the bank(s) for your demand, you will want to replace the converter/charger to one calibrated for lithium to recover the bank from shore power or the APU, and a DC-DC charger because the Lithiums charge at a higher potential than you main engine alternator likes.

Give me a couple of weeks and I can have a full proposal for you as I am working on that for a client right now.

Matt

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359367 is a reply to message #359350]

Sat, 10 October 2020 15:29

Husker92592

Messages: 137
Registered: August 2013
Location: Temecula ca

Karma: -4

Senior Member

So would these two batters be 12v? will there be a discharge issue? Yes I am looking that way and I want to add one or two solar panels to not onle keep the house batteries charged but the starting battery as well. One of the reasons I am upgrading my boost wire to 2/0 from front o back. My boost cable runs doen the frame rail and over the top of the radiator if that helps.
thanks

1974 GMC Sequoia 26'

Report message to a moderator

Re: Battery bank wiring for a 73 [message #359377 is a reply to message #359367]

Sat, 10 October 2020 17:22

Matt Colie

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

Karma: 7

Senior Member

Husker92592 wrote on Sat, 10 October 2020 16:29

So would these two batters be 12v? will there be a discharge issue? Yes I am looking that way and I want to add one or two solar panels to not onle keep the house batteries charged but the starting battery as well. One of the reasons I am upgrading my boost wire to 2/0 from front o back. My boost cable runs doen the frame rail and over the top of the radiator if that helps.
thanks

Grant,

If you are going with GC2s or Trojan T105, then you need 2. If you buy LiFePo4, buy the size voltage you want.

That is going to be a lot of money in copper. Be sure you protect it well. Either buy marine (fine stranded and tinned) or at least welding cable (fine stranded and neophrene jacket.)

Matt

Report message to a moderator

Previous Topic:	Transmission Break In
Next Topic:	Bump/thump while driving at low speed

Goto Forum:

-=] Back to Top [=-

Current Time: Sun Sep 22 07:30:32 CDT 2024

Total time taken to generate the page: 0.05611 seconds