Group 31 vs. group 34

[Matrix37495]

Sure mister 5 batteries...

Here's seths battery tray:

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[smokin150]

Ive been running one 31 size battery since i put the engine in my truck, never had any problems out of it, then again im a big rig driver and have plenty of spares lying around.

 

[MIDNIGHT RIDER]

I have seen where several people do this conversion and my question is why? I understand a few more cranking amps and I understand that getting the batteries out of the engine compartment and getting away from lead acid are a good idea, but why the group 31?

I have searched for a thread on this topic and was unsuccesful. I am really only interested in how and why this is necessary in the IDI's?

Thanks in advance for looking or responding.

I am a firm believer in the raw power and genuine dependability of the Group-31S batteries.

Most of my trucks have at least two of them; my personal truck has THREE.

Sure, in a perfect world, one little wimpy battery will start the engine, but I don't often live in this perfect world.


Lately, I have gone a step farther in the multi-battery situation by installing big constant-duty solenoids that separate the starting batteries from the accesssory batteries.


Two Group-31Ss are connected to the starter and ONLY the starter; the remaining batteries power EVERYTHING ELSE.

When engine oil-pressure reaches 5-PSI, the solenoid engages the alternator to the accessory batteries.

When the engine is not running, the accessory batteries are dis-connected from the starting batteries.

I can leave lights, wipers, whatever, ON until a fare-the-well without draining the starting batteries one iota.

 

[rhkcommander]

Lately, I have gone a step farther in the multi-battery situation by installing big constant-duty solenoids that separate the starting batteries from the accesssory batteries.


Two Group-31Ss are connected to the starter and ONLY the starter; the remaining batteries power EVERYTHING ELSE.

When engine oil-pressure reaches 5-PSI, the solenoid engages the alternator to the accessory batteries.

When the engine is not running, the accessory batteries are dis-connected from the starting batteries.

I can leave lights, wipers, whatever, ON until a fare-the-well without draining the starting batteries one iota.

That sounds awesome!

I have two group 31s myself, well worth the money.

They've done things that my older batteries wouldn't have done brand new

 

[Fordsandguns]

I'm currently running only one group 31 and it starts the truck better than the two 65 s batteries that it replaced. We haven't had much of a winter this year so it hasn't seen colder than upper 20's and it didn't seem to faze it at all.

 

[Matrix37495]

I've been running two G31s for a while now (a pair even came in the truck) and i love them. I'm thinking about add two more down on the frame to help out a rear mounted winch, and because i can...

 

[93cc7.3]

I've been running two G31s for a while now (a pair even came in the truck) and i love them. I'm thinking about add two more down on the frame to help out a rear mounted winch, and because i can...

Sure then u will have no room to talk about my 5 battries although replacing my 3 65's with two 31's wouldn't be a bad deal

 

[pennsylvaniabo]

more pics of how you guys are mounting twin group 31's!!!!!

 

[typ4]

also you cant have too much cranking power, the higher the voltage stays at the starter the longer the starter lasts. Quickest way to burn up a starter is to crank with low voltage.

 

[Agnem]

I run 31's because I have electric fans that continue to run after the engine is shut down, and I like to listen to my 12 speaker stereo for hours on end with the sub woofer woofing and my tweeters tweeting. No modifications were necessary. The cables were a little bit of a stretch with those posts in the center instead of the corners, but they worked. No mods to the tray were needed either. With my wide radiator, there is ZERO space between the ends of the batteries and the radiator. This post made me realize I need some updated pics from my engine compartment.

 

[pennsylvaniabo]

Mel, you do not have an ac condenser tho right?

 

[mooseracing]

That was impressive! It looked like a group 34 and it also appeared to be AGM.

Just googled it and it is about $220 and its AGM. The Deka is only $20 more and has a better warranty.

I used to use Diehard Golds, then switched to the Platinums when they came out. AGM is so nice, it takes a ton of more abuse as far as draining and sitting. I haven't had a battery puke from vibration even on my offroad truck though

 

[bike-maker]

On the 83-86 trucks, group 31's fit underneath the hood just fine.
Mine has the tall/narrow radiator with AC condenser.
Only thing I had to do was hack the lip off of one side of each battery tray (the one towards the center of the truck).
I made up a brand new set of cables, so length wasn't an issue for me.

 

[MIDNIGHT RIDER]

Only thing I had to do was hack the lip off of one side of each battery tray (the one towards the center of the truck).

All I remember doing was just setting the big HEAVY batteries over in there; I don't remember cutting anything out of the way.

I will have to look and see this lip you speak of and see if I might need to remove it.

Currently, all of my electrical business resides in a custom control box located where the right-side battery used to reside.

A GROUP-31S resides in the left-side tray; this is isolated for EVERYTHING except the starter.

Two more GROUP-31S reside in a hanger just ahead of the right-rear wheels; these batteries connect to the starter and ONLY the starter.

 

[bike-maker]

It's not much of a lip; only about 1/4". You could probably get away with just setting the group 31 on top of it.
I had the battery trays pulled out during an engine swap, so I went ahead and cut 'em.