Group 34 vs. Group 31 batteries

[jarheadk5]

I saw the article in the latest Four Wheeler about the new Optima Group 31 yellowtops, and was wondering what y'all think about going with a single G31 yellow, instead of two G34 reds.
Vehicle is an '87 K5 with a soon-to-be-installed 6.2L diesel, no A/C, a small stereo sys., 2 sets of aux. lights, a winch in the somewhat-distant future, and a 94A alternator.
Here's links to the specs pages:
Group 31 yellowtop - http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/commercial/technical_specs.html
Group 34 redtop - http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/automotive/starter/technical_specs.html

Advantages to a single G31 vs. two G34's as I see them:
- Less cost
- Less wiring complexity
- Less weight
And disadvantages:
- Less reserve capacity
- No backup
- Larger object to mount securely somewhere

Your thoughts????

 

[rjfguitar]

IIRC the batteries that we use in our semi trucks are group 31's and most trucks carry 4 of them. I would still want two, even with the big 31's.

 

[afroman006]

I would still get 2 no matter what you get. I am planning on getting a group 31 yellow top to use as my main battery and use my old group 34 redtop as the backup.

 

[mikey_d05]

I run two G34 reds in my DD with a Painless dual battery setup. ('93 fullsize Blazer on 33's) It's mostly used for a stereo wagon when camping and partying in the country. Back when it was warm here in MN (so long ago) we had a party out in the country and I was the designated sound system. One G34 redtop ran my stereo (1,500 watts) for a little over 6 hours. Having made the switch, I'd never go back to a single battery. I would, however, be interested in a dual G31 setup