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[GMCnet] *New Owner* Battery Bank Questions..... [message #327092] Thu, 14 December 2017 10:18 Go to next message
glwgmc is currently offline  glwgmc   United States
Messages: 1014
Registered: June 2004
Karma: 10
Senior Member
Hi and welcome,

The idea of full timing in a GMC primarily boondocking is more than doable so long as you manage clothing well and stay in relatively warm areas. You will find the storage space constrained trying to accommodate more than one season of clothing and it takes far more energy than you might imagine to keep a GMC warm in really cold conditions.

The AGM batteries you found are a great buy for 220 amp hours of capacity. Three of them will give you more than enough ampacity for full timing but will weigh close to 500 pounds so plan on placing them near the center of the GMC side to side for proper weight balance. The air bags will maintain proper ride height so end to end location is not as critical as long as they are towards the rear. Being AGMs you can put them inside the living area so under the bed is a good location if you have a permanent rear bed.

A simple marine combiner will keep your house and starting battery banks charged no matter which charging system is employed yet keep them isolated when living off the house batteries. No need for a separate gen battery. You will be very dependent on the generator day in and day out so if you keep the Oman (it is more than up to this task) then add an electronic ignition and install a dual fuel kit so you can run it off of gasoline or propane at the flip of one toggle switch. It will run better and last forever running off propane but you carry less of it so want the choice.

Get professional help before you try to tie the inverter AC output to the gen/shore power AC distribution box now in your coach. Safe grounding is the issue and do so,properly is not obvious. There are many advantages to running separate inverter AC outlets and leaving the existing shore/gen AC outlets in place. You won’t need too many inverter AC outlets anyway, and running 120vac wire is simple to do by routing under the floor and then up through the floor to where you want the outlet. Actually, 12ga appliance extension cords and power strips work really well for this purpose. In both our GMCs I did that with great success.

I suggest downloading two presentations I did at various GMC rallies. Both are available from GMCMI, GMCWS and other GMC club web sites. One presentation is called “You gotta live in there, baby” and discusses how to add battery capacity for off grid living. The other is called “Feeding the barbarian” and talks about setting the Oman up to run off of either gasoline or propane by flipping one toggle switch.

Ken already offered good points about load balancing and keeping as much as you can on 12vdc. The only places I would differ from Ken is I suggest you run the TV and satellite decoder from the inverter since you have so many better options at 120vac than at 12vdc, and how you power the microwave. Add an inverter 120vac outlet near where the 120ac shore/gen microwave outlet is now and plug your microwave into,the shore/gen outlet when you can or the inverter outlet when you can’t. Be sure your microwave will run properly from your selected inverter as many of the newer cheap microwaves will not. Sharp microwaves generally will, Panasonic Inverter microwaves generally will not no matter what the nameplate says.

I suggest the high quality battery operated blue tooth speakers for all your audio needs. We did that in our Prevost and like these little things far better than the monster Bose surround sound system we took out. Stream off your phone when you have internet access and use a high quality Walkman type tape player and CD player when you don’t.

Have fun and enjoy your new boondocking ride!

Jerry





Jerry Work
The Dovetail Joint
Fine furniture designed & hand crafted
in the 1907 former Masonic Temple building
in historic Kerby, OR
http://jerrywork.com
========
Message: 7
Date: Wed, 13 Dec 2017 23:34:50 -0700
From: austenm606@gmail.com
To: gmclist@list.gmcnet.org
Subject: [GMCnet] *New Owner* Battery Bank Questions.....
Message-ID:
Content-Type: text/plain; charset="utf-8"

Okay, so, I'm a new owner so please don't beat me up for dumb questions. I'm planning on full timing in this rig with mostly boondocking.

I wanted to add 3 Odyssey http://bit.ly/2Aonfek and hard-wire an inverter to the coach's electrical system. So, I'm not running a bunch of extension
cords and power strips like I'm Nomadic Fanatic or something.

If I want a new outlet, or something new I'd like it to be hardwired into the breaker box (call me crazy). Or daisychained if it isn't much of a
load.

The original idea was to expand the house battery setup. And hard-wire an inverter into the coach's electrical system. Add an auto transfer switch, a
smart charger and the MPPT solar charger.

*Of course, update the fuse box and whatnot

The problems with that is that it's 5 boxes and there's not redundancy. So, I leave something on and drain my batteries completely dead, I cannot
start my generator.

So, my brilliant idea is to run a separate battery bank and scale down the house battery as mainly a starting battery for the generator.

Then, I would pigtail a http://bit.ly/2CfxOS2 into the generator output. Allow the magic box to charge my batteries/ power my coach when the generator
is on and use as a inverter when it is off....... and this is how I die in an electrical fire.

I don't know how to do shore power with this dumb idea.

I'm not in possession of the motorhome, yet. It'll probably be first of the year before it gets back to me but I wanted to get my thoughts going in
the right direction.

I really don't want to run extension cords everywhere or have different outlets for inverter power and shore/ generator power.

Is there a best way to run an inverter into the main electrical system of the coach?

What are my options?

Is there a way to get a better result for less money?

I'm looking at $3500 for this system.
--
1977 Eleganza II,

26 Foot,

403 Engine,

Full time boondocking,

New Owner with Plans (deadly last words),
========
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Jerry & Sharon Work
78 Royale
Kerby, OR
Re: [GMCnet] *New Owner* Battery Bank Questions..... [message #327102 is a reply to message #327092] Thu, 14 December 2017 13:23 Go to previous message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
Jerry has some interesting comments of TV that I did not think about. I seldom watch TV and chose 12 volt ones to keep the battery drain to a minimum. If you are going to use satelite for reception then as Jerry says maybe 120 VAC on an inverter is the way to go. Any time you introduce an inverter there is some additional power loss over straight 12 VAC.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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