Chassis Battery - How Many?

[Smitty77]

I've read posts over the last few months, that indicated different coaches had different quantity and CCA sizing for their chassis/engine starting duties.

I suppose this is a 'Hmmmmm!' type post, but was curious about what others have in their coaches.

Hoping others would respond with:

Year = 2004
Mfg = Country Coach
Model = Allure
Chassis = Dynomax
Eng = ISL/8.9
Battery Qty = 1
Battery Type = 8D
CCA = 1500

In the above, of course fill in as appropriate for you situation.

For example, I was reading a post earlier today, that indicated the 2002 Winnebago Ultimate had two chassis batteries, and that 1800 CCA was recommended. This is with the ISC/8.3 engine. So why would a slightly large size ISL/8.9 have one battery with 1500 CCA (And I put in more starting CCA power when I change batteries, then was in the tray. Not OEM, so not sure if a lesser battery CCA was used when it was replaced the first time.)

Again, just Hmmmmmm information...

TIA, and best to all,
Smitty

[nothermark]

FWIW cranking amps are highest as the motor starts to turn and drop off with speed. It is possible to run at very low compression as the engine starts to turn over to reduce some of that power then engage full compression and the injectors once some speed is achieved and momentum built up. Probably not feasible with an all mechanical engine but a lot simpler with some of the electronically controlled one's. I do not know how much of that is currently done any specific engines. If they are using that technology it is conceivable that a newer bigger engine would draw less starting power than a smaller engine that did not employ the technology.

[MnTom]

Very good possibility that when the coach was made the battery was either one readily available that fit the spot or it was spec'd and built for the coach. More than likely it was a readily available battery.

[Harry B]

I have an ISL400 and use 2x 1000 CCA Batteries in parallel . It was set up like this since new

[wa8yxm]

Different companies think differently.. Now that 8D battery is roughly the same as two Group 31 batteries When i say Roughly the same, I mean Two Group 31's would about the same weight about the same cranking amps (When parallelled) about the same capacity (Amp hours) and so on, But when it comes time to pull them out and drop in new ones, they will be (each) 1/2 the weight and thus 4 times easier to wrangle.

This is also one of the reasons we use Six Volt batteries so much in RV's. you put two GC-2 Six volt in series you get, basically a 4D, but again you only lift half of it at one time so ....

There are other reasons as well but... This is why you have one very very big battery and some other rig with the same engine has two smaller ones.

NOT ALL 12 VOLT batteries are alike.. I have some that fit in my pocket and hold less than 10 amp hours.. I've used some that needed a fork lift to pick up..... but also could power that fork lift (and in fact did), they hald a whole lot more power.

[mel s]

Originally Posted by Smitty77

I've read posts over the last few months, that indicated different coaches had different quantity and CCA sizing for their chassis/engine starting duties.
I suppose this is a 'Hmmmmm!' type post, but was curious about what others have in their coaches.
TIA, and best to all,
Smitty

Smitty
My coach came new from SMC, (in Jan of '96), with two of these 660 CCA "chassis/starting" batteries:
Car and Truck Automotive Batteries - Buy a Vehicle Battery for Cars or Trucks | Interstate Batteries - Light Truck/Van Mega-Tron - INT Comm 18m Free - 660 CCA
Those 2 original chassis batteries where replaced, with 2 of the same Interstate batteries, in late Dec of '05.

Year = 1996
Mfg = SMC, (Safari Motor Coach Corporation)
Model = Sahara, (35')
Chassis = Magnum Blue Streak, by SMC
Eng = 250 hp 3126 Cat
Battery Qty = 2 "chassis"...4 "house"
Battery Type = Chassis: Interstate 31VHD, (group 31 maintenance free)
House: Interstate SRM-24, (12V Deep Cycle Marine & RV)
CCA (of chassis batts) = 660 each, (1320 total)
CA = 825 each
Mel
'96 Safari, 3126 Cat

[deandec]

My CC:

CT8.3L 300 hp Cummins

8D

two (from the factory)

1300 CCA each

[Smitty77]

Originally Posted by nothermark

FWIW cranking amps are highest as the motor starts to turn and drop off with speed. It is possible to run at very low compression as the engine starts to turn over to reduce some of that power then engage full compression and the injectors once some speed is achieved and momentum built up. Probably not feasible with an all mechanical engine but a lot simpler with some of the electronically controlled one's. I do not know how much of that is currently done any specific engines. If they are using that technology it is conceivable that a newer bigger engine would draw less starting power than a smaller engine that did not employ the technology.

Learned something new here, thanks for sharing that info.

I suppose this could explain why earlier smaller diesels, may require more robust battery CCA capability than newer larger batteries.

For example Dean's double 8D's in his era 8.3, compared to my single 8D (And the Deka Wet Cell 8D I removed was also 1300 CCA.) for the 2004 ISL.

Kind of interesting to me, and sure fits the 'Hmmmmm!' category!

And, I know most coaches have the auxiliary battery boost capability to link in the House Batteries to help too. So even with only X's 1 8D - I (and many others) have redundancy reserves of the house battery bank too.

Thanks to those of you who have shared, best to all,
Smitty

[dons2346]

Year = 2002
Mfg = Country Coach
Model = Intrigue
Chassis = Dynomax
Eng = ISC
Battery Qty = 1
Battery Type = 8D Lifeline
CCA = at 68F/1975, 32F/1675, and 0F/1350

The Champion wet cell that the Lifeline replaced was somewhere around 1300 CCA at best.

[Papa_Jim]

Year = 1995
Mfg = Monaco
Model = Dynasty
Chassis = Roadmaster S-Series
Eng = C8.3
Battery Qty = 1
Battery Type = 8D
CCA = 1300

[Wdebarmore]

Year = 1988
Mfg = Executive Industries
Model = Executive Prestige
Chassis = P30
Engine = 6BT 5.9L
Battery = qty 5 group 27 750 CCA each

Mine coach is different from most. Start and coach share same battery bank. Has another battery for generator. Also has switch to link all together.
So I have 3750 CCA total. Needless to say, it starts very easily.

[Smitty77]

Originally Posted by Wdebarmore

Year = 1988
Mfg = Executive Industries
Model = Executive Prestige
Chassis = P30
Engine = 6BT 5.9L
Battery = qty 5 group 27 750 CCA each

Mine coach is different from most. Start and coach share same battery bank. Has another battery for generator. Also has switch to link all together.
So I have 3750 CCA total. Needless to say, it starts very easily.

Wow, 3750 should give you enough capacity to crank it over a few times....

I have seen a few other coaches with generator dedicated battery.

When we upgraded our house battery bank, I did three layouts, one of these included replacing the chassis X's 1 8D with X's 2 L16's - linked with X's 4 L16's for house duty. (This would have raised my total bank to 1200AH from 800AH.) I liked the idea of going with all AGM in the battery bay, saw that as a positive. I also felt that the a total of X's 6 L16's would have provided solid chassis/engine starting duty. And of course liked the extra 400AH of house battery.

But, I ended up going with the CAT Maintenance Free 1500CCA 8D battery for chassis. Has gone well so far, as no signs of outgassing from this battery. It was a lower cost going this way, but it was not just the money. During my energy audit and calculations of what I felt I needed for a house bank size - 800AH I felt was plenty of capacity. And one 8D weight was just about 1/3 of two L16's. So not hauling around more weight then needed. I did also add one extra 240W 48V Solar Panel, for a total of 5 of them and 1200W of Solar Panel. This extra panel gave me extra capacity for keeping the house bank batteries charged up, was much lighter in weight, and was also about half the costs of just one L16 Lifeline AGM.

If I had had a smaller battery compartment, and was trying to maximize the house bank capacity - I feel that a 'combination house and chassis' battery bank is a viable option. At least worth considering.

Best to all, and thanks for sharing you Chassis battery and engine combo!
Smitty

[Ted E]

1 Chassis battery with battery boost switch to the house batteries.

[CountryFit]

Year = 2000
Mfg = Country Coach
Model = Intrigue
Chassis = Dynomax
Eng = ISC 350
Battery Qty = 1
Battery Type = Deka 908D
CCA = 1400