GMT-800 5.3 battery and dual battery question?

[Martinjmpr]

Another question for those with accessories: how do you get wiring through the firewall? Is there an existing fitting or grommet I can run wires through? I'm pretty confident that once I get through the firewall I can remove enough plastic panels to hide the wiring so I can run a dedicated circuit to the fridge but getting through the firewall itself is a puzzler. I don't want to drill a hole in the firewall.

 

[Burb One]

Another question for those with accessories: how do you get wiring through the firewall? Is there an existing fitting or grommet I can run wires through? I'm pretty confident that once I get through the firewall I can remove enough plastic panels to hide the wiring so I can run a dedicated circuit to the fridge but getting through the firewall itself is a puzzler. I don't want to drill a hole in the firewall.

Up(a 6 inches) and to the left (6 inches) of the brake pedal, there is a grommet that you can stick wires through.

With my solar, winch, CB, and exterior speaker setup, I have a few wires going through there and had to expand the grommet, but if it's just a few wires, you can just poke them through. It's a little low for my tastes, but I don't think's I'll ever go into water that deep, and even then the door seals will go first.

 

[Burb One]

Alright, so I'm getting down to the nitty-gritty here and trying to figure out which actual parts I will need.
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Thanks to forum member Jelorian for posting his awesome Z71 'Burb setup! From that I'm thinking that a pair of Blue Sea 5191 terminals to connect to the two positive terminals (since these attach directly the posts it keeps me from having to find a place to screw a fuse holder into the body of the truck.)
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Next question would the solenoid/isolator. Who can recommend a specific type and brand? And if I wanted one that automatically keeps the starting battery isolated until after the engine is running, which one would I be looking for?

Jelorian's setup is sweet, very similar to mine.

For solenoids my theory is to get the biggest one possible, especially when dealing with these full sized battery, and if you want to be able to keep starting power from either of them, IE also to be safe if you have a dead cell and it's going to pull power from the furthest battery,

For the price you can't go wrong with these: (If you wait/ shop them, I got mine for 30 bucks, but seem to usually be around $40-50)
http://www.ebay.com/itm/KISSLING-29...ash=item41a36bf082:g:wnsAAOSwoydWn6zk&vxp=mtr

They are a serious item, weigh like 5 pounds and are rated for like 500 amps continuous and something crazy like 1200 amps for 60 second or something. I use them for my winch and for my starter battery isolator.

 

[Martinjmpr]

Up(a 6 inches) and to the left (6 inches) of the brake pedal, there is a grommet that you can stick wires through.

With my solar, winch, CB, and exterior speaker setup, I have a few wires going through there and had to expand the grommet, but if it's just a few wires, you can just poke them through. It's a little low for my tastes, but I don't think's I'll ever go into water that deep, and even then the door seals will go first.

By any chance can you snap a photo of the grommet you're talking about? I can't find it. I'm thinking I may just route a wire through the fender opening in front of the door. Not clean, but easy. Once I get it to the dashboard I'm fine as I can hide it behind the dash panels (they're easy to get to.)

 

[Burb One]

By any chance can you snap a photo of the grommet you're talking about? I can't find it. I'm thinking I may just route a wire through the fender opening in front of the door. Not clean, but easy. Once I get it to the dashboard I'm fine as I can hide it behind the dash panels (they're easy to get to.)

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[chilliwak]

Hey Martin there is a guy on the site here that used a simple positive disconnect switch on the positive terminal of his avalanche. His name is HenryJ. But I gues you want to go with a more advanced system...:Wow1:

 

[Martinjmpr]

Battery size issue...

So for those who have a dual battery in their GMT-800, which battery do you use for your "house" battery? I have got the tray, the fused terminals and the isolator, but I need to get a battery.

The "starter" battery is a Group 34/78 AGM (Deka) but I'm having trouble figuring out my "house" battery. Ideally I'd want it to be at least a 100ah deep cycle battery, but everything I'm finding in that category is way bigger (physically bigger) than a 34/78, which is what (supposedly) the 2nd battery tray will fit.

So what I'm asking is, for those of you with a dual battery, what group-size battery is in your 2nd battery tray? I need to get some idea of how large a battery case I can fit.

Thanks in advance! :ylsmoke:

 

[rayra]

I'm pretty sure the group 78 form factor is the max fit for both factory trays.

googling around -

http://www.gm-trucks.com/forums/topic/109348-battery-group-size/

"The groups that will fit the 99-06 (07 classic) truck are 75, 78, 100, 34-78."


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I have 75s in my Sub and pickup right now, but planning to run dual 78s in the Sub factory locations. And possibly some additional 12V sealed battery(ies) in the power module I'm planning in back. Depends how much room I have there after I pick the other equipment and finalize the box size. It's going to be roughly 10"x9"x34" and have a couple inverters, a bus bar, solar charge controller, and a bunch of other power adapters / ports on the front and back ends. And a fat Andersen power pole connector tying it to heavy gauge cable running to the 2nd battery tray and to the rear bumper. Another fat power coupling there to power a winch or plug in jumper cables. Still working out the details of isolating, combining and fusing everything.

btw, there is a 'factory' isolator available on rockauto, dual batteries is after all a factory available setup.

 

[Martinjmpr]

I'm pretty sure the group 78 form factor is the max fit for both factory trays.

googling around -

So does anyone know of a 34 or 78 sized battery that has more than 55ah? I'm googling and searching and finding nothing higher.

 

[Ducky's Dad]

My GMC is a '98 K1500 and I have a pair of Optima Yellow 34/78s in the factory boxes. I think I could probably squeeze in an Odyssey Grp 65 if I tried. My Dodge came with a Grp 65 and I squeezed in a Grp 31 by using a belt sander on one end of the battery case ribs to reduce the length just enough to fit it in. That required a new hold-down assembly.

 

[PGW]

Like everybody else I am going to run two 78's in my 2003 Yukon XL. My research showed that is about as big as you can go. Will also be running a 100W solar panel. If that is not enough to run my fridge and misc items I will add a third battery somewhere, would have to be somewhere on the undercarriage or inside. Kind of amazing how little space there is in the engine compartment for batteries compared to Landcruisers etc.

 

[fiddypal]

Nit the exact same truck but close enough: http://www.expeditionportal.com/for...-1500-Working-Dog-Cross-Country-Cruiser-Build

Check out pages 1-3 I have a ton of pics, parts listed and diagram for the install. Also show how to route the wires in the back along the factory spot in the floor panels.

Hope it helps! I was looking for a bigger battery as well but ended up settling for a 70ah which match the stock battery in my truck. I'm only powering a fridge at the moment and have had no issues.