Tech 101 lowering battery tray for OBS G31 batteries.

riotwarrior

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Hey guys.

My son has a 93 CC 4X 7.3 ZF and we are building it up some.

Knowing Group 31 stud top dont fit well we have chosen to modify and lower the stock battery trays.

We removed the trays and mounts to the rad support.

Re removed those rad support brackets from the trays. We drilled new mounting holes 1" higher in rad support brackets.

We cut off the fender tabs off a couple of old battery trays I had floating around here and prepped and welded them on to fender tabs on sons obs trays.

He ground and sand blasted the trays and will laint them soon

I will get more pics tomorrow as I was busy today doing my front axle while he did his trays.

Here are a couple of teaser pics for the idea.

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He had yet to weld this up...

He tacked both sides up and we trial fit them..wowzers this works amazing.

I will be doing the same for my trucks soon

More pics soon.

Thanks for looking.
 

IDIoit

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the only problem is that the batteries don't fit all the way down inside the tray
 

riotwarrior

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the only problem is that the batteries don't fit all the way down inside the tray
We did a test fit and all that we found was a tappety tap tap of the hammer to the ends flaring them out....wait for pics as we already thought through that.

The inner fender cam take the 1 inch drop no issues so this will be alebiating the interference w the hood.
 

IDIoit

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I also noticed that the front clip wiring they conveniently put right in the ******* way
 

sjwelds

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Flare the end, hold down loosens up, battery slides into the fan shroud or radiator. Better to add so you still have end lip to hold batt in place
 

FORDF250HDXLT

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The "Group 31" are more of a deeper cycle battery than what our trucks come with? I've often seen you guys talk about these but I've never asked what your setups are for these? Are they for your campers and such so that you can run stuff longer at night between charging?
I ask because I've had no issues with the ones in chip truck with the dump or plow stuff and the ones in log truck with the auto crane have been issue free for years as well.Though these things are more of a quick on/off use and the engines are always running with 3g alts.So I guess it doesn't matter in this case,since the batteries are always charging?
I just put the same size battery in my box for the auto crane as well (though with a large cable running from the front battery.) Anyway,what group are our batteries in our trucks and what are you guys doing that require a larger group (deeper cycle if I understand them correctly?) Always been curious.
 

riotwarrior

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G 31 are just commercial transport truck style batts w significant reserve...not a deep cycle they are a starting battery. Any truck shop sells em....means easy replacement.

They are much better than what our trucks come with IMHO.
 

rhkcommander

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I just took my tray out a month ago, cut the bracket with the holes off and welded it to a flat piece of old metal shelving. Drilled two holes on the flat and bolted it in. also put a hole on each side for a battery hold-down bracket. Slapped some rubber material under the batt, Worked great!
 

riotwarrior

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Kid did some work today...we will get the trays coated now that we know how well batteries fit.

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Clearly there is room for the group 31 batteries...

Thanks for looking.
 

MIDNIGHT RIDER

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You can get them in either deep cycle or starting. The group just specifies a dimensional size. They come in different flavors of the same size for different purposes.


What ^^^ He ^^^ said; "Group" mostly specifies case dimensions; you can get several type variations within a given group size.

Although not as common as they used to be, there is also a Group-30, available in either lead post or stud; the case dimensions of the G-30 are identical to the G-31; the difference being that the G-31 has the terminals aligned with the centerline, whereas the G-30 has them offset to one side; I guess the reason the G-30 has became so rare is because a G-31 can usually be used in any application a G-30 is called for.

I have been using stud-type Group-31s in everything I can manage to fit them in for many years.

While most Group-31s possess superior cranking abilities and have a lot more bottom to them, I believe the one factor that makes them superior to other batteries is the threaded stud terminals; they are way better than any type lead post and lead clamp connection.

In my neck of the woods, I can buy fresh new appearance-blemished Group-31s with 90-day warranty for $60 apiece and the battery guy delivers them right to my door and picks up the junkers without me having to make a special trip, that is worth another $20; for years, they were only $50; I have never got a bad one and I usually get at least seven years before one gives up the ghost.
 
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drewr13NJ

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I know I am bringing this back from the dead, but I feel this should be put in the Tech Articles section. I will share my experience with this mod as well.

I did pretty much everything the same as riotwarrior. I took some flat stock and drilled oversized holes and welded it to the original fender mount tabs. I drilled holes in the brackets 1" above the original holes in the other brackets. I wire wheeled and sprayed some cold galv on the trays. Installation was very straight forward on the passenger side. I only got one bolt to go back into the rad support, but I was fine with that considering it was braced back to the fender. The driver's side was a little more challenging. I thought I was fighting the inner fender, so I cut some on it with the die grinder. In the end, I did some bending on the brackets under the coolant overflow and windshield washer bottle to get the holes to line up. I also added some 1" angle to the ends of the battery trays after grinding down the stamped factory lip. The battery is pretty tight on the drivers side due to the wiring harness being behind it on the fender side.

I also ended up installing some longer and larger ground cables from a truck I junked. The starter spins fast now and I am pretty happy with the setup. I bought batteries with stud connections on them but installed some post adapters on them from Amazon. With some additional tapping, I got them to fully thread onto the stud posts.

Also, I managed to get some Group 31's on sale at the local Rush Truck dealership for $60/ea! Too bad they wouldn't take the 65's for core! I was still money ahead even paying the core charge considering everyone else wanted about $100 or more for each battery.

Good luck trying this on your OBS truck!
 

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