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Battery Isolator: Noob Question


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#1 Mighty Dodge Ram

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Posted 10 September 2017 - 11:31 PM

I have a "new to me" 2002 Chevy 2500HD. It used to carry a Lance Camper. When starting the truck the first few times, I noticed an audible "clunk" coming from the firewall directly in front of the driver's position. I finally popped the hood and DUH, there's a battery isolator for the camper. And a connecting terminal attached to the alternator.

My question: unlike a National Luna "smart" solenoid where you have some control, this just seems to work in the background...I assume. How does this particular unit work? Does it block charging to the camper battery until the starting battery is fully charged? Or does it charge both simultaneously regardless of charge level and then block use of the starting battery once the vehicle is shut off? I've looked for this specific topic but my apologies in advance if my search skills are weak.

Note on the red terminal: the larger wire coming in from the left is from the "pos" side of the starting battery and the smaller wire coming from the right goes to the isolator.

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Richard
1996 Dodge Ram 1500 4x4, lightly lifted, ARB bumper/Warn winch, BFG AT/KO2, Snugtop shell. SOLD! But not forgotten!
2002 Chevy 2500HD XC LB 6.0L 4X4, Leer Hi-Rise shell, completely stock...for now!

#2 Mighty Dodge Ram

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Posted 10 September 2017 - 11:36 PM

This is a shot of where the camper "plugs into" the system back in the bed. Any insight into "post" assignment would be helpful. I'd rather just terminate this line into a Blue Sea fuse box for other uses. Possible?

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Richard
1996 Dodge Ram 1500 4x4, lightly lifted, ARB bumper/Warn winch, BFG AT/KO2, Snugtop shell. SOLD! But not forgotten!
2002 Chevy 2500HD XC LB 6.0L 4X4, Leer Hi-Rise shell, completely stock...for now!

#3 Mighty Dodge Ram

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Posted 10 September 2017 - 11:41 PM

Oops...just to demonstrate what a noob I am to this, I posted this in the wrong forum. Moderator(s), can you please move this to "Truck Mods"?
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Richard
1996 Dodge Ram 1500 4x4, lightly lifted, ARB bumper/Warn winch, BFG AT/KO2, Snugtop shell. SOLD! But not forgotten!
2002 Chevy 2500HD XC LB 6.0L 4X4, Leer Hi-Rise shell, completely stock...for now!

#4 Mighty Dodge Ram

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Posted 11 September 2017 - 01:47 AM

Thank you!
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Richard
1996 Dodge Ram 1500 4x4, lightly lifted, ARB bumper/Warn winch, BFG AT/KO2, Snugtop shell. SOLD! But not forgotten!
2002 Chevy 2500HD XC LB 6.0L 4X4, Leer Hi-Rise shell, completely stock...for now!

#5 Wandering Sagebrush

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Posted 11 September 2017 - 03:31 AM

Thank you!


No problem! You're not alone in the wrong forum club, I think most of us have done that...
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#6 klahanie

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Posted 11 September 2017 - 03:56 AM

How does this particular unit work? Does it block charging to the camper battery until the starting battery is fully charged?
 

Appears to be a simple on/off battery solenoid, commonly used in a simpler time passed. It is controlled by trigger voltage applied to the center terminal and grounded thru the mount (on your model). Often the trigger voltage is an ignition-on hot source, off when ignition is off. I think you stated the trigger is wired to the pos batt terminal which would make the solenoid on "all the time"(??) so I'm not sure about yours. You stated the 12v load comes from the alternator (and poss main battery if batt is connected to same terminal on alternator) and presumably that power goes to the trailer plug - might just be a factory trailer set up.

 

This is a shot of where the camper "plugs into" the system back in the bed. Any insight into "post" assignment would be helpful.

 

If you google search for 7 pin trailer wiring, you should find a diagram similar to this.

 

7-pin-trailer-connector.jpg

 

If you search for Chevy trailer wire gauge you might find the oem gauge for the 12 volt charge wire(s), useful to know for your fuse box load although it may have been upgraded...

 

Hope that helps some


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#7 ntsqd

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Posted 12 September 2017 - 12:22 AM

Cole-Hersey constant duty solenoids, which is what that appears to be, are on when what their trigger terminal is connected to is on.  Usually that is an ignition source, so no connection delay while the starting battery(ies) are being recharged.


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Thom

Where does that road go?

#8 Mighty Dodge Ram

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Posted 12 September 2017 - 06:00 PM

Thanks WS for letting me off the hook and your encouragement.

Klahanie: thanks for all the work you put into your reply. This helps me to connect the pieces of the puzzle. Your diagram of the 7-pin trailer connector is right on and what I'm used to seeing...the more modern "blade" type of connector. I'll assume that the "pins" seen in the 3rd pic I posted are what was used circa 2002.

Ntsqd: thanks for confirming my sketchy anecdotal research on the solenoid. I now see that Cole-Hersey offers another type which does have a connection delay but I'm with you, a solenoid of this vintage probably does not. My MIL had little info on the install (unfortunately, my wife's father passed just 6 months after we began dating, he would've known the details) but I'll assume that the camper power was installed aftermarket.

So this brings up my next question: I'll be using this truck "as a truck" for awhile, ferrying materials up to a cabin in the San Bernardino Mtns. I will be installing some type of canopy for security purposes now and as a camping platform later. I also want to run an auxiliary battery but locate it under the hood. There is a designated location on the passenger side up against the firewall and available parts from GM to do this. I'm "familiar" with the National Luna style systems that seem to find favor with quite a few overlanders. But is there any reason that what I currently have or even an updated Cole-Hersey with a connection delay couldn't do what I needed it do with a new aux battery under the hood? I'm talking about powering my ARB fridge, running some radios, a few lights, some other accessories, etc. Sure, it doesn't have all the features of a NL unit but it would be far more economical and convenient in terms of set-up.

Thanks in advance for your thoughts.
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Richard
1996 Dodge Ram 1500 4x4, lightly lifted, ARB bumper/Warn winch, BFG AT/KO2, Snugtop shell. SOLD! But not forgotten!
2002 Chevy 2500HD XC LB 6.0L 4X4, Leer Hi-Rise shell, completely stock...for now!

#9 klahanie

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Posted 13 September 2017 - 03:04 AM

 Your diagram of the 7-pin trailer connector is right on and what I'm used to seeing...the more modern "blade" type of connector. I'll assume that the "pins" seen in the 3rd pic I posted are what was used circa 2002.

<snip>
 But is there any reason that what I currently have or even an updated Cole-Hersey with a connection delay couldn't do what I needed it do with a new aux battery under the hood?

Yes I think pins or blades, the config will be common.

 

fwiw, not to spend your money but if you don't have one... an inexpensive bulb type circuit tester or multi tester can be a very worthwhile tool to have around.

 

Ok, I've found the subject of charging batteries can be a bit of a rabbit hole - doesn't have to be, but it can be. There's a lot I don't know and because of that I'm cautious of "is anything wrong with" or "whats the best" type questions. So I'll answer your question this way ... I had basically the same "needs" and set up on my previous truck and it worked fine for me. I did have the coil (trigger) wired thru a dash mounted switch (powered from an ignition hot source) that could prevent the solenoid from turning on to give me some flexibility. This could also be used as a delay. Downside is user forgetfulness but my backup is that my wife is pretty good at helping me remember things ... Alternately, I think one could wire in a 12vDC time delay relay for connection delay, if desired.

 

Still doesn't address keeping your starter batt fully charged first. How long you drive after re starting might be a factor here. One of the reasons I had a dash control switch was to prevent draw down if I was only moving the truck around. as always, YMMV


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#10 ntsqd

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Posted 13 September 2017 - 01:32 PM

I bought and installed those same OEM parts on my '91 Suburban for the same reason. For a more typical dual battery install where one is to be the primary while the other is dual role as a 'house battery' and emergency jump-starter I would use an Automatic Charge Relay/Voltage Sensing Relay (ACR/VSR) in parallel with a marine battery bank selector switch. Run the heavy cables to the switch, jumper across the switch with more appropriate wire size to connect the ACRVSR. Be sure to buy a dual sensing ACR/VSR so that no matter which battery the switch is set to, the other battery will also be charged. With a dual sensing ACR/VSR you can, and probably should, periodically switch the battery's roles.

 

NL has name recognition with Overlanders in this country (no idea about elsewhere), Blue Sea Systems and BEP Marine have world-wide reputations in the deep water marine world. If something fails offshore it is a bigger problem, and the environment is somewhat more hostile to start with. My friends & I have been using marine components to build reliable ground vehicle systems since well before "Overlanding" was a term used in US lexicon.

 

I just was forced to completely re-wire our Phoenix camper and used wire from bestboatwire.com, a Blue Sea fuse block form the Channel Islands Harbor West Marine, and some other bits from pkys.com


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Thom

Where does that road go?




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