Minimum battery size for starting

Jeremy · January 16, 2012, 09:23:17 AM

Quote from: jjrbus on January 16, 2012, 06:27:09 AM
Starting batteries do not make good house batteries. For house use you want deep cycle batteries. Google deep cycle batteries and you will learn more than you ever wanted to know.

That's true but unfortunately the term 'deep cycle' is thoroughly abused by battery manufacturers and retailers. True deep cycle batteries - the kind used in fork-lift trucks and industrial equipment - have really thick plates and are quite different in design to starting batteries. The thick plates also mean that the batteries will last for years and years, but they are expensive to make and don't give good 'numbers' (primarily because the surface area of the plates is limited). So such batteries aren't sold through high street retailers, where price and performance-on-paper is important. With some leisure batteries I suspect the 'deep cycle' bit doesn't go much beyond the label stuck on the outside.

Jeremy

John316 · January 16, 2012, 09:36:08 AM

For the record, this is my definition of a deep cycle. http://www.trojanbattery.com/Products/8D-AGM12V.aspx

Those are about $500 each. That is pricey. Flooded 8D's aren't that expensive in comparison.

chev49 · January 16, 2012, 10:03:51 AM

I have found that the best place to buy batteries is from the wholesale place, mainly because i have to buy lots of equipment batteries. I think the group 31's are the best over all, mainly because of weight and the 8d types don't seem to last any longer anyway.

I like golf cart batteries for house batteries... although i recently found out they have cell tower batteries which weigh almost as much as an 8d, but it would take several to make up a house system.

Lin · January 16, 2012, 12:08:01 PM

The best price I have found for 8d batteries here is $170+ tax. Interstate was a bit over $200. Even Sam's was in the $190 area. It would be nice to find it cheaper. Clifford, will mentioning I know you get me a discount?

CountingFireflies · January 16, 2012, 12:36:11 PM

Thank you everyone for your comments. All this has prompted me to do a bit more research, as I think now that the size of the batteries is not what is important. What matters is the amperage the starter needs to turn the engine. So, I found this chart on the delco-ramey site regarding the 50MT starter:

http://www.newindo.com/delcoremy/images/delco%20remy%20starter%2050MT-24V_pc_sm.jpg

Based on this, if I can provide over 800 amps, I should be well into the power curve.

Chris.

luvrbus · January 16, 2012, 01:44:40 PM

Check out service bulletins from Delco 1B-216 and 1M-153 it explains the voltage and CCA for the Delco, the 8v92TA service manuals calls for 900 amps on a 24V 50MTstarter turbo 8v92 1150 for a N/A non turbo 8v92

I noticed I gave you the max CCA sorry about that

good luck

robertglines1 · January 16, 2012, 01:53:46 PM

If your around any bus nuts have them ck out their local Oil/farm direct supply jobber. I pay far less for 31's than what people are saying here. Just bought last set. for $62 each Have had good service. The ones in the 89 are 5 yrs old and are strong as new. Name brand. Been getting 8 to 10 yrs with proper maintenance.

RJ · January 16, 2012, 07:09:13 PM

Chris -

The one thing nobody's mentioned yet is voltage drop.

If your starting batteries are still in the OEM location, you've got nearly a 40' run to the starter. Granted, it's a big cable, but voltage drop is something to consider.

Your MCI is also 24 volt, so that, too, has to be figured into the mix.

OTOH, the big 8Ds were spec'd for another reason not often mentioned: keeping the electrical supply somewhat consistent when operating the OEM HVAC system. If yours has been removed, then you've eliminated that heavy electrical load from the coach.

Many busnuts have gone to the smaller 31s with a tie-in to the house systems, a very common setup.

Perhaps Sean will pop in here and pontificate some on the finer points of this discussion. . .

FWIW & HTH. . .

TomC · January 17, 2012, 12:10:20 AM

With my bus being 12v and all trucks in the U.S. being 12v, I forget that many of the buses are 24v. Of which, you'd have to use either 2 or 4 12v starting batteries. Two size 31's are enough. On my truck I have 4 size 31's with the truck running on 12v and the starter using 24v through a series/parallel solenoid. But-a big 14.6 liter 4 stroke is much harder to turn over then the 2 stroke. Good Luck, TomC

luvrbus · January 17, 2012, 05:26:08 AM

Yep size does make difference the 12L- 8v92 takes a little more to spin than a 9L- 8v71 both fire fast 1/2 turn not like the newer 4 stroke electronic engines

good luck

RnMAdventures · January 17, 2012, 10:16:23 AM

Quote from: CountingFireflies on January 15, 2012, 02:27:25 PM
Howdy -

I'm trying to be frugal with my new battey purchases, and the starter batteries have me perplexed. I have an 8v92TA, and I currently have 2x 8D 12V batteries with a Vanner system. Each battery spec's at 1380CCA. The 8D's are rediculously expensive. Given that my engine starts on the first revolution, can I get by with 2x 31 size cells with 800-900CCA? What's the minimum CCA to get that beast turned over?

Chris.

Continential 8D's aren't too expensive. If you add thermoil it is supposed to triple the life of the battery. I would be reluctant to under power your coach batteries, it just ain't worth it. It may still crank, but if you wile out the starter you will pay for it there 3 fold.

CountingFireflies · February 12, 2012, 10:23:16 PM

Just a follow up on this. I've been running with e size 31 starter batteries since this post, and they seem to be adequate. I've been in the southern climate, so nothing too cold yet. I can tell it's not got the oompff that the 8d's had. It doesnt have quite the snap when it turns over. Anyway, for those that were curious like me.... There you have it.

Cheers
Chris

jjrbus · February 13, 2012, 05:51:09 AM

RJ is the only one that pointed it out, the reason for the 8D's originally, was not for the starter but as a buffer for the huge draw of the over the road AC system. JIm 0311

luvrbus · February 13, 2012, 06:20:31 AM

That is not really the case on some buses the Eagle with the batteries mounted in the rear close to the engine used 3 group 31 for factory air 35 or 40 ft of battery cable back to the starter you have a drop in voltage no way around it.

Like Chris posted I used 2 group 31 in place of 2 -8D on a 4905 Sunday to start the engine it was no comparison with the 8D's I removed for charging maybe 4 would have better the 2 for 24v sucked

good luck

Ed Hackenbruch · February 13, 2012, 07:22:23 AM

To add a little more info to my post, ( number 14) I have a 24v starter, no over the road AC, but do have the over the road heat and blowers....and my batteries as still up front in the original position. Lost prime a couple of years ago and it took awhile to get it going but the batteries did just fine for all of the cranking we did with it. Sorry Clifford, as soon as i touch the button she fires off.