Battery Isolator: Noob Question

[Mighty Dodge Ram]

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.

 

[Mighty Dodge Ram]

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?

 

[Mighty Dodge Ram]

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"?

 

[Mighty Dodge Ram]

Thank you!

 

[Wandering Sagebrush]

Thank you!

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

 

[klahanie]

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.

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

 

[ntsqd]

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.

 

[Mighty Dodge Ram]

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.

 

[klahanie]

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

 

[ntsqd]

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

 

[Mighty Dodge Ram]

Bringing this topic forward again with some additional questions and different approach:

I have not installed a second battery under the hood (yet) and in the interest of keeping the truck as a truck (using the bed to transport building materials, hay, etc), I bought an ArkPak 730 with a 105ah marine battery inside. I also purchased a Lance Camper power “pigtail” to properly connect to their proprietary power port that had been installed in the front of the truck bed. It’s controlled by a simple separator under the hood. It has 8awg power/ground leads with ring terminals which will connect to the ArkPak terminals. Should I install a fuse in that pigtail before attaching to the ArkPak? Additionally, I’m adding 100 watts of solar through a 30 amp controller. Should I fuse that line prior to connecting to the ArkPak? If the answer is yes to either/both questions, can you recommend an in-line fuse that is appropriate for the “portable” nature of this setup? I have a Northern Nevada desert trip coming up and want to power my ARB fridge.

Thanks in advance for the wisdom of the tribe.

 

[ntsqd]

I had to go look up what an ArkPak is. I'm not seeing the benefit, but that's neither here nor there. Any time you pull power off of any battery you should run that thru a fuse or a breaker. That is to say that there should be circuit protection at both batteries.

I'm a fan of manual reset breakers. I use the 285 series for most of my projects. Can use them as a switch to turn off the circuit (Both of them or the circuit is still live!) when you need to work on that system etc.
https://www.delcity.net/store/EATON-Manual-Reset-(Switchable),-Surface-Mount/p_823674.h_821984

As to adding circuit protection to the solar system, I see that as a judgement call. Yes, there is power there, so there should be some circuit protection. However, the circuit is not capable of the kind of discharge that a battery is, so what is prudent?
Right or wrong on our last camper I connected the solar charge controller's output to the camper battery side of the breaker. Some argue for circuit protection in the feed from the panel. I didn't do that, but I can't fault the idea.

 

[Mighty Dodge Ram]

Thanks for the info and advice ntsqd. When (if) I go with a more permanent camping setup (either in a real camper or even under my shell) I’ll probably go with the circuit breakers you reference. They look to be a very clean arrangement. Since this must be by necessity an easily installed/removed setup...cot, storage box(es), fridge...I’m looking at something less traditional.

Following on your fusing location advice, I went back out to the truck to check on something. Sure enough, right next to the simple separator on the firewall is a 2-pole breaker, I’m assuming it’s self re-setting. The Lance manual (originally on the truck re: post #1) called for the separator and breaker to be mounted in the camper but for whatever reason there they are under the hood. And, there is a mega-fuse between the truck battery and the separator. So already “fused” close to the truck battery as you suggested. I’m going to use an inline 40 amp maxi-fuse at the ArkPak...that’s the amperage Lance called for in the manual. Installed at the end of the pigtail before connection to the ArkPak, I’m hoping this is sufficient. In addition, I’m going to fuse from the solar controller to the battery with a 30-amp inline fuse. You mentioned having not fused from the panel to the controller and I’m going to follow suit. Deeper research showed less than 10 amps of fuse is suggested so I’m not going to bother. BTW: I wasn't having any luck with my previous research until your response prompted me in the right direction...thanks!

As to why the ArkPak: in the past I used an aux battery in a basic plastic (flimsy) battery box. No fuses, wires running everywhere, no power ports, no inverter, etc. I’m aware that I could build something from my own design but that requires buying all the assorted parts mentioned and putting them together. Doable, but the ArkPak is sturdier and allows me to charge in any vehicle with the “BCDC” plug. On long trips in the wife’s Suburban, the fridge would occasionally blow a fuse due to the small gauge wire running to the back power port. The ArkPak draws power more slowly so no shut offs, fridge runs off separate aux battery, and it’s easier to move around. For right now, this setup works for what we need in several environments. But noted, comparatively pricey next to other solutions. I knew that going in. Thanks again for helping me get my head around this and the subsequent needed research...meaning shopping. LOL

 

[craig333]

I had to go look up what an ArkPak is. I'm not seeing the benefit, but that's neither here nor there. Any time you pull power off of any battery you should run that thru a fuse or a breaker. That is to say that there should be circuit protection at both batteries.

I'm a fan of manual reset breakers. I use the 285 series for most of my projects. Can use them as a switch to turn off the circuit (Both of them or the circuit is still live!) when you need to work on that system etc.
https://www.delcity.net/store/EATON-Manual-Reset-(Switchable),-Surface-Mount/p_823674.h_821984

As to adding circuit protection to the solar system, I see that as a judgement call. Yes, there is power there, so there should be some circuit protection. However, the circuit is not capable of the kind of discharge that a battery is, so what is prudent?
Right or wrong on our last camper I connected the solar charge controller's output to the camper battery side of the breaker. Some argue for circuit protection in the feed from the panel. I didn't do that, but I can't fault the idea.

Handy when you're trying find a short. Reminds me of a project I was (maybe still am) going to do. I got a bunch of circuit breakers at an aircraft wrecker a long time ago.

 

[ntsqd]

OK, Now I see why the ArkPak and your logic behind it makes sense to me.

If I had a large amount of solar power I would fuse or breaker it near the panels. For the systems I've had so far (100W & 160W) coupled with the knowledge that neither produces it's max amperage due to how they're mounted it just doesn't seem necessary.