Explain auxilary battery purpose to me

[CG]

So I have a C30 ex motor home that has the auxiliary battery. Can you explain how its wired into the system and what exactly is the use. When you use the electrically powered devices in a motor home my guess is they feed off the extra battery some how. Thanks for any insights on how this system works.

[flashed]

Im interested in this one .

[Getter-Done]

CG
My Grandpa's truck which is long gone was wired like that.
It was a 71 Custom camper/20.
He had a in the bed camper the we would load in the bed and go to Gatlinburg TN
Here is the 2 pics I have of the truck.



The two 12 volt battery's are wired parallel which keeps the system running on 12 volts and are wired so the Alternator will charge both battery's.
The one battery is isolated so that only power is drain from it to use the lights or whatever else in the camper part of the truck.

[Andy4639]

Simply put.

The main battery which I call the normal battery is for cranking the truck and running the normal stuff in a regular truck.

The second battery runs all the camper electrical stuff normally.

Now if you have it hooked up like it's suppose to be you can charge them both while the motor is running are if you need to you can use either one to crank the truck are vise versa.

[jocko]

What they said. Here's some additional info:

[Coley]

Great post Jocko....very interesting and helpful!
I've always like the idea of having the secondary battery system...even in my 1/2 ton, which I use to pull a small travel trailer from time to time.
Not that I have a dual battery set up....but I'd like one.
In the meantime, I've mounted a second battery in the trailer and isolated it...but it doesn't get charged during driving...at least not yet.

all good
Coley

[Steeveedee]

Since I don't have one, but based on the information above, the auxiliary battery would be a deep drain version. They aren't good for use as a starter battery for an engine, at least more than a few times. I have a pair of deep drain batteries on my travel trailer. They are switched from under the hood so that while dry camping the trailer doesn't discharge the truck battery, but the trailer batteries can be charged while driving the truck. So, if the trailer batteries go dead from over use, the truck battery will start the truck so that we can leave the campground...if we were even in a campground. Sometimes we camp out in the middle of nowhere. I have a portable generator as a backup, in case I forget to flip that switch...

[burnin oil]

Originally Posted by Coley

Great post Jocko....very interesting and helpful!
I've always like the idea of having the secondary battery system...even in my 1/2 ton, which I use to pull a small travel trailer from time to time.
Not that I have a dual battery set up....but I'd like one.
In the meantime, I've mounted a second battery in the trailer and isolated it...but it doesn't get charged during driving...at least not yet.

all good
Coley

That is an easy fix. Make sure the truck has a fused power lead to the 7 way trailer connector. Then on the trailer make sure there is a lead from the coresponding connector to the battery. Most RVs are wired this way but the trucks tend not to have the power lead. Some trucks are wired up but missing the fuse unless you have the trailering option on newer vehicles.

[jeffahart]

Originally Posted by burnin oil

That is an easy fix. Make sure the truck has a fused power lead to the 7 way trailer connector. Then on the trailer make sure there is a lead from the coresponding connector to the battery. Most RVs are wired this way but the trucks tend not to have the power lead. Some trucks are wired up but missing the fuse unless you have the trailering option on newer vehicles.

And when dry camping I would always unplug the 7 pin just for good measure. You can camp comfortably for a weekend using two deep cycles on a travel trailer, since the fridge runs on propane.


j

[CG]

Good info. I knew they charged together but was unsure how if they charged together how come they didn’t discharge together.

[special-K]

The key to this system is a battery "isolator" for directing what is hooked up to what while charging or drawing on the system.

[67chevemall]

Great info. I want to find a second tray to hold another battery for my 12000 winch. Pull the trees out to the build site. And pull the truck out when I get it stuck

[jeffahart]

Originally Posted by 67chevemall

Great info. I want to find a second tray to hold another battery for my 12000 winch. Pull the trees out to the build site. And pull the truck out when I get it stuck

If you're getting a second battery for your winch, I would just run dual batteries in parallel. Get a couple 700CCA EverStarts from Walmart, wire in parallel and spend your bucks on the cable. I run #4 for power and #2 for ground. Configure to use shortest amount of cabling as possible. Your winch motor is more like a starter motor than any other accessory.


j

[weq92f]

Originally Posted by jeffahart

If you're getting a second battery for your winch, I would just run dual batteries in parallel. Get a couple 700CCA EverStarts from Walmart, wire in parallel and spend your bucks on the cable. I run #4 for power and #2 for ground. Configure to use shortest amount of cabling as possible. Your winch motor is more like a starter motor than any other accessory.


j

In this case, what charging setup changes are required?

Any pictures?

-klb

[jeffahart]

Originally Posted by weq92f

In this case, what charging setup changes are required?

Any pictures?

-klb

You don't really need any charging changes. Just some wiring finesse. The second battery adds capacity, much needed capacity. I added a 150amp tuff stuff though.

Here's my setup. I wire the alt through a submersible 200amp breaker to the battery pos using #4. I ground the alt to block with a 10 guage, and also ground the alt to the battery with #2. I wire the pos to the winch solenoid with #4. I ground the winch body to the battery with #2 and the small ground as per install instructions back to the solenoid. All the other power wires on the winch running to and fro the solenoid are #4.

I only have one Walmart Everstart 700 CAA, but I am adding a second battery soon, been dragging my feet! I have run the winch a few times with no issues.


j

[jeffahart]

Originally Posted by jeffahart

You don't really need any charging changes. Just some wiring finesse. The second battery adds capacity, much needed capacity. I added a 150amp tuff stuff though.

Here's my setup. I wire the alt through a submersible 200amp breaker to the battery pos using #4. I ground the alt to block with a 10 guage, and also ground the alt to the battery with #2. I wire the pos to the winch solenoid with #4. I ground the winch body to the battery with #2 and the small ground as per install instructions back to the solenoid. All the other power wires on the winch running to and fro the solenoid are #4.

I only have one Walmart Everstart 700 CAA, but I am adding a second battery soon, been dragging my feet! I have run the winch a few times with no issues.


j

One other note. If I had an auxiliary setup, I would wire the winch to the starter battey, and have that battery fed from alt.


j

[Coley]

Does anyone have any pics and references to these factory GM battery 'isolators'?
I think I might have one, but I'm keen to see what the standard/stock ones look like.

Coley

[El Dorado Jim]

the way the factory isolated the batteries was to use a constant duty solenoid,when the vehicle is running, the solenoid allows the spare battery to be charged , when the key is turned off the camper or trailer is drawing power from the spare battery only. for those of you that want to run a winch, you would only run the winch with the vehicle running anyway so not a need to have a second battery

[Bigdav160]

From the schematic above the isolator appears to be just a HD relay. Perhaps the same part as a horn relay.

[Andy4639]

This is a thread on my ramp truck aux battery setup. Done the way I like it wired. Newer parts and it works great, I can turn the relay on/off from the cab. All the accessaries are relay feed from the contactor by a dash mounted switch also.
The solenoid is a 12v /400amp unit. I use these all the time in the golf cart's I build to run lights and stuff off the carts pack voltage of 36/48 volts.



The thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=780350

My contactor are solenoid which ever you prefer to call it.

[Bigdav160]

Those contactors appear to be a little pricey ~$75. I guess a horn relay would be too light duty. A Ford starter solenoid work?

I need to set something up for my car trailer battery.

[100%Chevy]

Originally Posted by Bigdav160

Those contactors appear to be a little pricey ~$75. I guess a horn relay would be too light duty. A Ford starter solenoid work?

I need to set something up for my car trailer battery.

My old Warn winch uses 4 ford style solenoids.2 for the forward and 2 for the reverse.They are sized for the load and all ford style are not the same.

And,isolators(for charging batteries) are available aftermarket.I have 1 on each of 2 of my trucks.
One is to charge the batteries on my travel trailer and the other is on my car hauler.They sense the lowest battery and charge that battery only.
A large relay is needed to isolate or switch from one battery to another.
Mike.

[jeffahart]

Originally Posted by Bigdav160

Those contactors appear to be a little pricey ~$75. I guess a horn relay would be too light duty. A Ford starter solenoid work?

I need to set something up for my car trailer battery.

The solid state stuff is more expensive, plus 400amp. I would definitely watch what Andy does, looks like he deals with batteries on the modified golf cart scene. What I was going to add is, I paid a few more bucks and upgraded to solid state for my winch. I hope to never touch it again!


j

[Coley]

Does anyone have a pic of a stock/factory one mounted in original position?

Coley

[Andy4639]

jeffahart,
thanks, yes I have built many carts using these type contactors, and they get the job done. I have never had one to fail me yet in over 20 years of modifying carts. They are continuous contactors and you can buy them for any voltage you need.

If you want it to be factory correct then you don't have much choice as to what you can use for the parts but if you want it to just work right and last for a long time. Then use the right kind of parts for the job. As far as those Ford solenoids go have you looked at their amp rating?

The short of it is that it takes 8-10 amps to hold the solenoid in place while starting your motor the draw can spike to 30 amps while it is engaging the car starter.
A winch will over load these as soon as it starts winding. 100 amps and higher if the winch has any kind of load on it.

http://www.smittybiltdepot.com/aux_i...7.pdf&line=S/B