Aux Battery Atwood Connection Question and ACR 7611 too

Josh41

Adventurer
I'm running an aux battery in my truck bed for the Habitat, noticed fridge turned off from low voltage, no milk for coffee. Got home and started poking around with the volt meter. Aux battery in truck bed at 11.41 volts. Truck running 13.99 volts at batt, 13.97 past ACR(not sure why passing through when just started, maybe part of the issue). Checked voltage on both sides of inline fuse and good, still 13.97. Checked atwood plug (female) in truck bed, still good. Plugged in Attwood plug from aux battery, voltage still 11.41 on aux, no juice to aux then. Unplugged Atwood, checked that I wired aux to Atwood correctly and yes, the wires I thought coming from aux read 11.41. Conclusion, the Atwood installed on truck with 3 studs are smaller than the receptacles in the plug and not making contact, see pic, on the aux battery plug (they were purchased separately). Or, is there something that I don't understand about the ACR?
Your input is appreciated.
Josh


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Josh41

Adventurer
Update, spent some time checking the connection, it works, full voltage going through to battery. Battery was low, 11.41 volts. So, am I getting enough power to the second battery? I think part of the problem is I only drive 2 miles to work, and I don't have permanent solar panels, I do have a folding 100 watt, but haven't connected it yet. I put the aux battery on charger in garage, I'll bring it back up to charge, then not sure what to do.

I still have a few questions if anyone is a battery/charging pro:
  1. Why didn't the truck charge the low battery on a 2 hour drive? Is 11.4 volts just too low to bring back?
  2. Is there a way to check that enough amps are coming through my set up to the aux battery?
  3. The Blue Sea ACR 7611 seems a little weird to me. It lets full voltage through when I start the truck, I thought it waited 10 minutes, and then closed the circuit, am I wrong (see drawing above)?
  4. When the truck is off, the aux side of the ACR reads about 4 volts? Why? I expected nothing.
 

dwh

Tail-End Charlie
Update, spent some time checking the connection, it works, full voltage going through to battery. Battery was low, 11.41 volts. So, am I getting enough power to the second battery? I think part of the problem is I only drive 2 miles to work, and I don't have permanent solar panels, I do have a folding 100 watt, but haven't connected it yet. I put the aux battery on charger in garage, I'll bring it back up to charge, then not sure what to do.

I still have a few questions if anyone is a battery/charging pro:
  1. Why didn't the truck charge the low battery on a 2 hour drive? Is 11.4 volts just too low to bring back?
  2. Is there a way to check that enough amps are coming through my set up to the aux battery?
  3. The Blue Sea ACR 7611 seems a little weird to me. It lets full voltage through when I start the truck, I thought it waited 10 minutes, and then closed the circuit, am I wrong (see drawing above)?
  4. When the truck is off, the aux side of the ACR reads about 4 volts? Why? I expected nothing.
  1. No, not too low to bring back. A 2hr drive should raise the voltage a good amount.
  2. Clamp meter. Most only do AC. Get one that also does DC.
  3. 10 minutes? What are you smoking dude? And did you bring enough for everyone? :) 30 seconds...or less...RTFM.
  4. You should expect to see aux battery voltage at the "B" terminal if the ACR is disconnected. Only seeing 4v means either a bad connection between the aux battery and the ACR, or a bad ground, or you shouldn't drink before using a meter. :)
 

MANUCHAO

Aventurero
Rig something up, and check your voltage with a cig lither or voltmeter as you drive ...on both batteries.......
You should be getting 14v + on (each) both batteries....
You just might be lucky to have one of them smart alternators.....
What is your alternator rated output ?

As stated above check your connections.....

I have an ACR on my old trusty LC.. going strong on 10+ years now...
I tried using the same set up on a 2016 subie outback... it did not work...as it has a smart alternator....
Not saying that's what it is.... but might be part of the issue at hand....

Edit:
I dont drive my LC everyday and when parked... it has a NOCO battery tender to keep the batteries topped....
Good practice if you dont drive that much or have 2/3/4 battery system...
 

Josh41

Adventurer
I think the problem has been found. It looks like the wire after the fuse in the engine bay, after the ACR to the socket in the bed of truck has too high a resistance, likely due to corrosion in the back of the socket (exposed to weather) or the connections made by the installer that originally put this in for my FWC. Picking up some wire and a new port, will try and install this weekend. FWIW we were able to test this with a the ohm meter setting on the multi meter.
On another note, it has come to my attention that the multi meter will switch units freely based on current. So when hooked up to a fully charged battery, it will read in volts. When a low to no current situation it will read in millivolts. This did throw me off for a while until I figured that out. I'm sure someone's eyes can read those little units, just not mine. So I was seeing 4 millivolts (essentially nothing, not 4 volts).
Best I can tell, no smart alternator, just corrosion.
Thank you, your comments were helpful, glad I figured this out.
Josh
 

Josh41

Adventurer
The positive lead to the Atwood plug in my truck bed. Note: Part of my FWC install 2 years ago by the dealer.


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dreadlocks

Well-known member
oof, this is why they make tinned cable and marine shrink wrap, that whole run is likely full of cancer now and needs to go in the bin.
 

Alloy

Active member
That is a heat shrink terminal.

Only 2 years old.........something else is going on............
-Heatshrink was split by the crimping tool
-Soldering flux is involved
-Electricity is leaking.
 
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