Well, I was already considering myself talked out of Optima, but that seals it. No freakin' way...

(I wonder if Johnson bought the Interstate brand at some point in the last decade. A change in ownership would explain their sudden switch from a high quality battery to a useless POS....)

EDIT: Uh oh... Found this article about Johnson Controls... Guess what brand battery is in the picture...
http://www.themanufacturer.com/us/pr...hnson_Controls

Then again the article mentions Sears as one of their big customers, and I've never been anything but happy with DieHard batteries (well, except for the crazy price), so maybe it's not that big of a deal... Maybe they're a company like Sony, produce both best of breed stuff, and also produce cheap, useless crap.

EDIT #2: OK, after finding out a bit more about Johnson Controls, I'm no longer put off by them simply being the manufacturer. It looks to me like they produce products for other companies based on a spec that they are given. Sears can send them specs on plate material and chemistry and they'll say "hey, that's going to be expensive, but if that's what you want, we can make it for you". Then Interstate can come in with different specs and they'll say "hey, that's going to be a crappy battery, but if that's what you want, we can make it for you".

After a bit of research, it looks like they are the company behind most of the brand names out there (in car batteries), both good and bad. I no longer see them being the manufacturer as a particularly relevant point.

 

i just replaced my FACTORY 03 D battery with a regular duralast and I live in WI, **** gets cold round here, no problem with those either

 

You put Marine batteries in the trailer and Automotive batteries in the truck plain and simple.


In this post the user states that the truck is charged when plugged into the trailer and the trailer is plugged in. This is incorrect with a factory OEM style 7 way round plug. When you shut off the truck with the key switch the Battery Charge connection to the trailer is severed. Now when the truck ignition is in the run position power will flow to the trailer connection to charge the battery while driving or running. This why the battery can charge while driving.

The reason that your alternator output is changed from it's normal read position in the cluster while hooked up is because of the added load on the charge system, because you are also powering the trailer and charging the trailer battery.

 

I was attributing the lower voltage to an average output from the two trailer batteries and the D battery combined. It is possible that I am incorrect. I wasn't even looking at the voltage gauge though. I have a battery minder in the trailer that shows me the constant voltage of the 12v system. It reads in the high 12's when the D is connected (not running, Ignition off) Then when I unplug the D the voltage bounces back up to the mid 13's. I just took my test light out and found 12v at my factory 7-pin connector with the keys in my pocket. What does that mean? My JGC did the same thing...

Thanks to you Guys I have realized that it's probably risky (based on some of the remote locations that I take my rig) to rely on the D as a "back-up" power source. I'll just do a properly sized GLD, and put more effort into getting green. My biggest drain are the lights, the fridge and water heater are propane and TV is an LCD. The Generator is a Champion that I got from Cabela's and isn't quiet like those expensive ones, but does great and isn't as loud as it could be...

 

This means your 7 pole connector 12v lead is connected to a constant battery power lead, and not switched. Not sure if it's factory, but if it was done aftermarket, it was done wrong!

I did all my wiring myself in my shop and I actually ran it from a ignition switched lead and created it's own fuse in the dash box. I believe it is right for it to only be a live 12v lead when the key is on.

 

That is very strange as the hot lead is supposed to be fused.

Anyway, it makes total sense as your deep cell battery's most likely are in better condition then your trucks. When you plug in the truck (and it is off) it is at a lower charge voltage so power flows from your trailer to your truck. This again is very strange as the connection on the truck should be switched off and it isn't.

Anyway, if you start the truck and you are plugged into the trailer the voltage output from the trucks alternator will be over the trailers battery's and that should max out your meter minder thus the reason you charge while you drive.

 

I kinda figured it was normal... My Jeep Grand Cherokee's wiring was aftermarket and installed by the Dealer where I bought the TT. The D has the Factory towing package (the build sheet told me so) not to deviate, but my build sheet states that there is a 136 amp alternator, but also have the Heavy Duty Service Group and the Trailer Tow Group... Would those options trump the 136 Amp alternator and mean that there is actually a larger Alternator? Anyway, would it be creapy if I was to cruise the mall to find D's to test for 12v at the trailer plug :-)

The whole Idea of having a built in third battery that I could "lean" on was to find out if I had a combo battery and only drained the bank to 50% would I still have enough reserve to crank and start the D... Granted, I don't think it's a great Idea, but that was my thought process.

 

I understand your idea, and the logic behind it, but my recommendation is still don't do it.

If your camper needs more capacity, add more deep cycles to your camper. Carry jumper cables with you, and you can charge them back up off the D in a pinch, but don't just leave the harness plugged in with your D battery powering your TV or Radio all night. You'll get away with it once or twice, and then you'll be "that guy" walking around the campground begging for a jumpstart.

Just make the camper work the way you want it as a self-contained unit. You'll be much better off, and have more enjoyable camping trips in the long run.

 

Thank you! That's the current plan.

I was looking for a wiring diagram to see if I could figure out the constant 12v to my plug. Anybody know where I could locate that? I'm thinking that maybe I should put a relay in line and possibly decrease the resistance to the trailer with a larger gauge line that is switched by an Ignition on source...

 

If you look at the plug in on the backside, there's 7 wires obviously, and the black should be the hot 12v lead. For future reference, here is a typical diagram for the trailer wiring: