Battery/charging question:

[Bamtech1]

Truck is a 1996 (mostly) 2500 4x4

I recently purchased a used Palomino “Real Lite” Soft side truck camper. I want to add an extra battery in the truck bed, the camper is prewired for it in the left front corner.
Should I run a dedicated charge wire to that battery, and if so how should I isolate it so that it charges while the truck runs but disconnects with ignition off? Alternately, I could just let it charge thru the 7-way, but that’s a little wire (10ga?)

 

[mwilson]

Constant duty solenoid and dedicated charge wire.

This or something similar....make sure whatever you get is "Continuous Duty", not "Intermittent Duty"....

https://www.amazon.com/Cole-Hersee-...coding=UTF8&psc=1&refRID=K0E1PXHRP9QCNJ24M7XN


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[Bamtech1]

Thanks. I’ll need to do some figuring on that setup.
I also needed to put an extra 7-way in the bed for the trailer lights. Camper came with a pigtail that reaches from the socket down by the hitch, 9 footer I guess? But I need that one for the car trailer.
The bed I put on was previously set up for a 5th wheel, had a hole for a plug in the left tailgate post. Not quite enough room there and no access with the camper on, so I cut a new one below the left front stake pocket.

Now just have to figure out where to splice it all. Maybe a junction block by the hitch?

 

[B.G. Smith]

Before you spend a lot of time and money let me tell you from my experience. You will never get full/satisfactory battery charing from the truck system because the alternator is wired to look at the truck battery voltage and controls from that. The solenoid is a good idea but won't solve the problem. Back in the day there was a battery isolater with alternator field wire hookup so you could switch from the vehicle battery to the house battery and alternator saw the voltage of the battery it was charging. It also had isolator diode so batteries copuld not series each other. If you dry camp your best bet is to get a small gas powered gen set for charging, if you don't dry camp then the converter in the camper shoul be sufficient. JMHO

 

[Bamtech1]

Before you spend a lot of time and money let me tell you from my experience. You will never get full/satisfactory battery charing from the truck system because the alternator is wired to look at the truck battery voltage and controls from that. The solenoid is a good idea but won't solve the problem. Back in the day there was a battery isolater with alternator field wire hookup so you could switch from the vehicle battery to the house battery and alternator saw the voltage of the battery it was charging. It also had isolator diode so batteries copuld not series each other. If you dry camp your best bet is to get a small gas powered gen set for charging, if you don't dry camp then the converter in the camper shoul be sufficient. JMHO

Thanks for the tip. We do dry camp a lot, but I have a 100watt solar rig that keeps up with our limited needs- just a few minutes of LED light here and there and charging electronics. But...that was the other camper-only a fully analog absorption fridge. This unit has a fridge that needs 12v control voltage plus has a circulating fan. Also has a propane furnace with a 12v blower. I do have a Honda 2k, but lots of places won’t allow them
Really just wiring for whatever situation arises, ever know what you’ll run into. I can get good group 31 batteries free from the core rack, so that’s what all my junk has if they’ll fit!

 

[mwilson]

I can get good group 31 batteries free from the core rack, so that’s what all my junk has if they’ll fit!

Same here Brother!! Unlimited supply of perfectly good Group 31 batteries at my disposal!! If they don't fit I get a different battery box so they will fit!!!

 

[Bamtech1]

I haven’t seriously looked into whether they will fit under the hood of my 96. Might have to fab some boxes?

 

[JR]

I haven’t seriously looked into whether they will fit under the hood of my 96. Might have to fab some boxes?

Going by memory here, but my 98 had group 27's. If that's what you have in your 96 there is 7/8"-1" difference in length and1/4"- 3/8" in width - the 31 being the larger battery of course.

Height isnt enough difference to worry about.

I've done some rough measuring in my 14 and am convinced 31's will fit. The one hang up may be the battery cables themselves, they are tailored to the OEM battery which has a different post position than the 31s.

 

[GAmes]

........the alternator is wired to look at the truck battery voltage and controls from that. .

How does it differentiate? If the aux battery is drawing from one of the batteries, which is hooked in parallel with the other main battery you have three batteries in parallel. The alternator can't just pick two and charge them, in fact it is only charging one. The other main battery, and in this case an aux battery, is drawing power from the one being charged. An '06 PCM might be monitoring two batteries, but a '96 sure isn't. 2nd gens do not come with isolator to the battery power wire, so one must be added for when the engine isn't running. A simple diode would do the job.

 

[B.G. Smith]

I just went and looked at the old isolator that I still have. It only has three terminals, Batt.#1, Batt.#2 and alternator. Evidently this device was only to isolate the camper battery so it could not run the Truck battery down. I don't know if it can differentiate voltage between batteries. It was rated at 130 amps. So my original post was/is misleading on the part about the isolator.​

 

[Bamtech1]

Yeah, I’ve noticed that the ‘aux’ red wire in the OE 7way is always powered. Will have to run that through whatever solenoid or isolator I come up with for the extra battery in the bed.
I did finally get the extra 7way in the front of the bed connected. I don’t know how or if this is usually done, leave it to me to do it the hard way! Used a weathertight junction box and just cut the plugs off the factory hitch harness. Made my head hurt. After 25 years of wiring tractors and trailers the colors/functions are just ingrained. The cable I used has 6 12ga wires and 1 10ga. The 10 wire is white and used as ground usually. I wanted it to be the charge wire. Went sideways from there.

View attachment 110646

The big cable barely fit in the rv socket, so I basically wired it according to how the conductors laid in the sheath. Guess the bus box is a good thing. At least I can pop the lid off and see what color is what! Kinda like Johnny Cash said: had one on the left and two on the right, but when we pulled out the switch all three of ‘em came on.

 

[lmabey]

Truck charging system is only designed to top off starting batteries not deeply discharged deep cycle batteries that need a higher voltage for bulk charging.

https://www.rversonline.org/ArtFAQ8.html

Also check out bestconvertors.com. an upgraded power center (converter) with a three stage charger will benefit you if you go the generator route instead of solar. Just Picked a boondocker power center with a 4 stage charger for $215.