Group 31 battery questions

[Iceni John]

I'm in the process of changing from two 8D starting batteries to two Group 31s, and I have some questions about whether more CCA or CA is actually better or not.   I have a 6V92 and a 42MT starter, and I'm in relatively temperate Southern California with no intention of taking my bus anywhere cold.

1.   O'Reilly can get me Group 31s in 1260 CA / 1125 CCA / 195 RC amps  -  these are the highest capacity Group 31s I've found in this area.   All other Group 31s here are between 950 and 1050 CA.   TomC and others here say they can easily start a Detroit with two 950 amp Group 31s.   I know that 42MT starters especially don't like low voltage or they'll burn up, unlike newer geared starters that tolerate low voltages better.   What would be the advantage of O'Relly's high-capacity batteries over (much cheaper) lower-capacity ones from other retailers?

2.   I assume that all batteries sold in Southern California are "Southern" batteries, with a lower rating than equivalent "Northern" batteries.   The higher-capacity "Northern" batteries supposedly have spongier plates than "Southern" batteries, and hence a shorter life as the plates inevitably break down quicker with age and fall to the bottom of the case.   Does this mean that O'Reilly's higher-capacity batteries have spongier plates than lower-rated batteries from elsewhere, and hence a shorter life?   In other words, is it worth spending more for maybe less durable batteries, especially if I may not need their extra cranking capacity?

3.   Does a higher-capacity battery, such as O'Reilly's, produce a more consistent voltage than a lower-capacity battery while putting out the amps needed by the starter?   Will the starter see less voltage drop with these batteries while cranking?

I've read all the battery FAQs I can find, but nothing I've seen so far addresses these questions.   One reason I'll be changing batteries is to have shorter cables  -  the old 8Ds used 20ft-long 4/0 cables to get to the Cole-Hersee switch and down to the starter, but the new batteries will be only a few feet from the starter.   I'll be shortening my existing cables (they're welding cable rated at 600 volts!), and all the extra cable left over will be more than enough for the house batteries and eventual PV system.

Thanks, John

[robertglines1]

I have 4  ea 1150  group 31's  8v92. was designed to carry bus air etc  I paid 46$ each from jobber last year they usually last me about 6 years maintained. The 98 has a 60 series and only has a place for 3. So it depends If you still have your bus heat and air electric motors on how much storage you need combined with starting reserve.  Hope this helps.  Bob

[demodriver]

The heat will kill a battery more so then the cold. So atleast I have been told.

Eric

[white-eagle]

The heat will kill a battery more so then the cold. So atleast I have been told.

Eric

true.  the water boils out, plates buckle, etc.
Bob's comment about maintaining only applies if you can add water/electrolyte.  if you can't add, then you are limited to cleaning the  terminals.  keep the dirt off the tops, spray the terminals.  i'd buy the 900+ CCA 31's.  not that much more.  also look at the weight.  sometimes the weight tells you the lead content where the CCA could be fudged.  usually, the higher the weight, the higher the cca.

[TomC]

Most batteries are sealed now.  My last two Interstate 31's (950cca) are sealed.  Start the 8V-71 (high compression) just fine.  Was in Mammoth Lakes this summer and was 38 degrees in the morning-and it cranked and started just fine.  If I have problems, can hit the jumper solenoid to have the deep cycles kick in also. Have started the engine on the 2-8D deep cycles when my starting batteries went dead.  I would stick with the 900-1000cca batteries.  Much higher cca than that means the lead plates are thinner-more affected by vibration and road shock.  Two 900's will work.  Good Luck, TomC

[bigjohnkub]

Some batteries are measured (CCA) at o degrees and  some at  32 degrees. look at the top of the battery.

Big John

[Busted Knuckle]

OK for an RV or conversion I'd just go to WalMart and get the best 31's they carry and be happy with them. The reason I say WalMart is they are everywhere and if you have a problem just pull into a WalMart and get them replaced.

On a bus in service I like to use NAPA batteries for the same reason.
My drivers can pull into a NAPA anywhere and get them warrantied.
Or at the very least I have had NAPA deliver the batteries to a hotel and the driver swapped 'm out. (he already had the old ones out)
The reason for NAPA is almost all NAPA stores still stock 8D's and if they don't they can get ts no crap about the commercial use of them that WalMart would!
  BK 

[Uglydog56]

I started a friend's 855 cummins yesterday with one 1150CCA group 31.  It had been sitting for 6 months.  I had to push in the clutch or it was pretty slow.

[Oonrahnjay]

I started a friend's 855 cummins yesterday with one 1150CCA group 31.  It had been sitting for 6 months.  I had to push in the clutch or it was pretty slow.

My bus has a 680 inch, 6 cylinder diesel (4-stroke).  It was built to have a pair of 6-volt batteries in a case underfloor in front of each rear wheel-arch.  The four batteries together in series gave 24 v; not sure of the amp-hour or CCA that was provided by the total.  I was talking to the mechanic for a company in Philadelphia that has about a dozen buses like mine, used for in-town sightseeing tours.  He told me that they use a pair of group 31's but he thought that one would be enough if he could find a 12v starter.  I've installed 2 group 31's, it starts in 4 seconds after a fuel filter change at 35 degrees.

[gus]

In my area WM doesn't carry Gp 31, their largest is Gp 27.

In my area Sam's used to carry GP 31 but now carries only Gp 29 which I now have as house batteries. I can see very little difference in them and the 31s in size or performance. In fact, they are the exact same size in the deep cycle.

You should have no problems with two 31 starts in SoC, I used two 31 for my 671 in my 4104 and it started with no problems in temps in the 20s in WY a couple of times.

Like Tom, if they seem a bit slow I connect the house to the starts.

[jjrbus]

I used Walmart batteries, cause they are like Chikenman they are everywhere. Then due to a change in corporate policy had a warranty issue with them. So now am a NAPA convert.

Don't cut out the old battery wire until you have designed your house system, it can be used to cross tie your bus and house system!  JIm

[DW SD]

I have a 6V92TA with a 12V starter and only one 8D starting battery.  Works great.  I'm in San Diego and the coldest I've been is 17 degrees at 6500 ft. in Williams AZ last Spring.  It was snowing.  I ran the block heater and it fired right up without any hesitation.

I've got the engine start battery well separated from the house and generator start battery.  It therefore remains constantly 90% to 100% charged @ 12.7V to 12.75V.

Hope that helps,

Doug

[gus]

Doug,  I agree, two 8D starts are overkill for a conversion unless you live in the frozen northern wasteland. I have two because the bus came that way but plan to go to one when one fails and to two 31s when the last one goes.

Worked fine in my 4104 for five years and there is always the option of using the house batts for boost in emergencies. I've done that a couple of times when the alt failed on the 4104.

[GMC5303Wonder]

John,

All batteries that are rated at 12v have the same "voltage" capacity.  Meaning you can charge them with as much voltage as you wish but anything over 13.4 or so and they will boil over.
Oreilly batteries are made by either eastpenn or johnson controls.  Both are good manufactures of batteries.  Oreilly used to carry strictly eastpenn batteries but has been changing over recently to johnson controls.  Napa is still exide I believe.

The biggest thing with cca's you want to look at is the temperature and voltage they are being rated at.  If the voltage is higher than 12.5 the rating could be misleading.  Oreilly and all other "heavy duty" commercial battery manufactures don't make a warm or cold climate battery so you should be safe either way no matter where u buy. 

Hope this helps and good luck.

Noah

[TomC]

When ordering new trucks, we have a simple rule of thumb.  If the truck has a Cummins 6.7, 8.3, or 8.9 liter-we order it with 2 batteries.  If the truck is a day cab-meaning no sleeper we order it with 3 batteries.  With all sleepers, it is standard to have 4 batteries-mainly to have sufficient amp/hours to run the small refer, your TV, 12v coffee maker and microwave and still have it start.  Also standard on the sleepers is a 12.1 volt cab cut off.  If the batteries get down to 12.1 volts, the shut off device will beep, then shut off the cab and sleeper lights.  You can still run down the batteries if you leave the outside headlights and clearance lights on all night (don't ask how I know this).
If you have a 6-71, 6V-92, 8V-71, 8V-92, Caterpillar C10, 11, 12, 13, Cummins L10, M11, ISM, 2 size 31's will be sufficient-but with the addition of a jumper solenoid for assistance from your house batteries.  If you live in cold weather and do alot of driving in the cold with a 12vdc starter-3 batteries would be better.  With any of the big block engines like Series 60; Cat 3406, C15, C16;  Cummins NTC,  N14, ISX I would run 4 batteries-especially if you have a 24vdc starter.  Good Luck, TomC