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Author Topic: Changing to Group 31 Batteries  (Read 10666 times)
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4108, 8V71 w/auto .


« Reply #15 on: May 17, 2007, 05:44:10 PM »

My local NAPA is open on sunday. 10:00-4:00 Guess I'm just lucky that way!  Grin Grin Grin

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What I create here:   www.amstudio.us
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Fred Mc
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« Reply #16 on: May 17, 2007, 08:42:49 PM »

So if "Group 31" refers to size only then what is the difference between a Group 31 and an 8D of comparable CCA?

Given that a Group 31 is physically 1/2 the size of an 8D and 1/2 the weight what do you get with an 8D that you don't get with a Group 31? What other ratings are important other than the CCA?


Fred Mc.
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Roanoke, VA
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PD4106-1063 "Wheezy Bus"

« Reply #17 on: May 17, 2007, 09:27:14 PM »

North vs. South batteries:

I wish I had more time to put into this but I am leaving tomorrow in the bus and will have to get up early to get ready, so I hope this makes sense.

Yes, there is a difference in the batteries and there is a good reason for it. But like everything else there is a trade off with what you get. All batteries contain what the battery manufactures call pasting. Think of pasting like a sponge, lots of holes and surface area. A northern battery has thinner lead plates and more lead pasting on the plates. That is how they get the higher CCA out of them and keep the same case size.  The problem with the thick pasting is that it breaks down faster than thin pasting, itís not as durable. If it flakes off and falls to the bottom of the battery it can short out that cell. Even Southern batteries have pasting but not as much, instead the Southern batteries lead plates are thicker. If you ever get to take a battery apart you will see what I am talking about. So, Northern climate batteries have a higher cranking current but the trade off is in longevity. If it where me I would rather have the Southern batteries because they are tougher and last longer (in theory).

If someone could say this with more clarity, please do so, I just donít have the time to do this topic justice. If I am wrong, let me know, so I can go back to the battery distributor that educated me and correct them. Wink
« Last Edit: May 17, 2007, 09:32:09 PM by Barn Owl » Logged

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« Reply #18 on: May 17, 2007, 10:28:26 PM »

Fred Mc- read my post on page one on the cca differences.  2 size 31's at 950cca each flip over my 8V-71 fine.  Good Luck, TomC

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #19 on: May 18, 2007, 04:49:40 AM »

Given that a Group 31 is physically 1/2 the size of an 8D and 1/2 the weight what do you get with an 8D that you don't get with a Group 31? What other ratings are important other than the CCA?

As I understand it:

  • Cold Cranking Amps (CCA) is the current delivered for 30 seconds while keeping the battery voltage above 7.2 volts at 0į F.
  • Reserve Capacity (RC) is how long it takes a fully charged battery to discharge 25 amps until the voltage drops below 10.5 volts at 80į F.
  • Amp Hours capacity is how much current a battery will discharge over an hour although most are rated based on a 20-hour discharge period.  (i.e. 200 amp hours is 10 amps per hour for 20 hours)

Amp Hours
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« Reply #20 on: May 18, 2007, 06:26:29 AM »

Quite a bit of battery information has been collected and posted on the Help board under the topic Favorites here: http://www.busconversions.com/bbs/index.php?topic=3071.0
If you have any additional links, I will be glad to include them.

BTW, I am really looking for Repair facilities across the country and links for the ones I have. With the start of the vacation season, a good list of repair facilities would be nice to have.

BK, please add your information if you want it on here.
« Last Edit: May 18, 2007, 11:47:52 AM by DrivingMissLazy » Logged

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1954 GMC PD4501-066 8v71TA

« Reply #21 on: May 18, 2007, 10:15:33 PM »

True NAPA stores aren't open on Sunday but it is very, very seldom that a man doesn't have some warning that he is going to need new batteries. There are certain indications that batteries need replaced. I try to monitor mine closely.

All I can say is you obviously don't live in the southwest. In AZ, getting any warning that a battery is going bad is the exception, not the rule. Here, if your battery seems weak on startup, go to the store *now* for a new one. But usually, you don't even get that much warning.

« Reply #22 on: May 21, 2007, 08:55:24 AM »

Okay, which Walmarts actually carry group 31 batteries?  I have never seen group 31 batteries at any local Walmart, but we also don't have any Supercenters here yet.  (They are coming.)  I don't recall if I've ever looked for group 31 batteries at any of the various Supercenters I have stopped at in my travels.

A local truck dealer is selling group 31s with 1200 CCAs for $62.50 which is much better than Sam's Club, but what happens if a battery dies away from home?

I need to bring out four new group 31s to my bus the next time I want to take it out of storage.  I did some bad things to the batteries and now they won't hold a charge for long.
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« Reply #23 on: May 22, 2007, 10:37:02 PM »


What part of AZ are you in?

I'm currently park in North Phoenix in the Deer Valley area.


Auburndale, Florida
V-6-92 Detroit, Allison 5 spd auto
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