whats the best batt set up

[reelnative]

I have to go buy some batts and I can get 4 group 31 interstate blems for 175ish or 2 non blem 8ds at 200 ea, now the 8ds have 1400 cca and I think 225 res for a total of 2800cca and 450 res,

the 4 group 31s are 1000 cca ea and 185 res ea for a total of 4000cca and 580 res.

my thoughts are if one of the 8ds goes bad im stuck but if one of the group 31s goes bad I can just rewire and still start and go, also would just 2 group 31s be enough to operate the bus them having 2000cca and a 380 res total

[Sean]

Are you talking about house batteries or starting batteries?

I just did a long piece on house batteries for the magazine.  Also, we've discussed them here extensively.  The search feature here should be your best friend; use the one on the left of the menu bar, between "help" and "profile" -- it is much more powerful and complete than the quick-search box above and to the right of it.

I am guessing from the last part of your question, though, that these are start batteries.  I start my bus with two group-65 batteries from Wal-Mart.  Two group 31 batteries are more than adequate.  You only need to keep the 4d or 8d size if you still have the OEM blowers in the coach.

Here are some threads on start batteries:
http://www.busconversions.com/bbs/index.php?topic=275.0
http://www.busconversions.com/bbs/index.php?topic=14139.0
http://www.busconversions.com/bbs/index.php?topic=2855.0

-Sean
http://OurOdyssey.BlogSpot.com

[Dreamscape]

I have three group 31's, two will start it OK. If the ambient temp is 50-60 that is or you've pre-heated.

Paul

[Sean]

I have three group 31's, two will start it OK. If the ambient temp is 50-60 that is or you've pre-heated.

Paul, he's got a 24-volt coach.  Significantly less than half the current as required for your 12-volt coach.  We start our 24-volt coach with only two group-65 (smaller than group 31) in temperatures down well below 40, although I admit we try to preheat if we can below that temperature.

-Sean
http://OurOdyssey.BlogSpot.com

[Gary '79 5C]

Sean,

Good information, I have a 24V bus with starter, marker lites, drivers defrost/heater fan motor as the 24V loads. All A/C's on the roof are 120VAC, headlites converted to 12V. I still have 8D's for start batteries, but they are 5 & 6 years old. I just slowly recharged, cleaned and refilled, and they are staying up.

Since I am getting close, my question is what life are you getting with the group 65 batts ?? I know you are starting & charging more often than my infrequent use. I would regard that better for the batteries.
I am on the fence about replacing with the 8D's.

Thanks,

Gary

[buswarrior]

In layman's terms, the question is most often one of geography for most busnuts.

If you will be starting it in the cold, you need to match/surpass the original capacity, if you stay warm, cut it back and you'll have more beverage money.

happy coaching!
buswarrior

[Dreamscape]

Sorry for the bad information, I should have known better!

[niles500]

Reel - Not withstanding how I feel about Interstate - That's a ripoff - My last trip to NAPA (inside deal but not that great @ about 35% off what you can walk in for and negotiate yourself) was $70 a piece for maintenance free group 31's - HTH

[reelnative]

the 31s will cost me about 40.00 each 175 was for 4 batts and including tax and all that

[Fredward]

I have two Group 31 Optima (Yellow case) for starting my 871. I still have 24v headlights and the heater/defrost fans are still original but no AC. The group 31s work fine but it only starts without preheating down to about 50; maybe 45. I don't know how good my 871 is but it doesn't seem too worn out. I'm guessing more battery would yield better starts. Or locating the batteries where the AC compressor was. Minnesota is why they invented 8Ds you know.
Fred

[Sean]

Since I am getting close, my question is what life are you getting with the group 65 batts ?? I know you are starting & charging more often than my infrequent use. I would regard that better for the batteries.

I've got just a little over four years on one of the pair, and the other one had to be replaced a few months ago at just a tad under four years.  By contrast, of the pair of 8D's they replaced, one had not even lasted two years.

To be honest, I would have preferred Group 31, but they were simply not available where and when I needed them.  I got the biggest thing they had in the store.

I should also point out that I have a bridging solenoid.  So whenever the pair of start batteries is not up to the task, I just flip a switch and start from the enormous house bank.  Typically this happens when we've been sitting for a couple of weeks, and it's cold out.  There are lots of parasitic loads on the start batteries, and we don't have any charging for them while we are parked (although I have wiring in place for a charger for that purpose, which we've never bothered to acquire).  If I did not have that option, I might be inclined to have a larger start bank.

-Sean
http://OurOdyssey.BlogSpot.com

[niles500]

In the infamous words of Emily Latella (sp?) - Never mind 

[robertglines1]

why reinvevt the wheel  ...proven set up as is....not that much money involved for securty.

[Don4107]

8Ds normally have only a 1 year guarantee since they are assumed to be in commercial service.  My experience as a battery dealer and user is they don't seem to last as well as smaller batteries.  Maybe my view is skewed because around here they are almost always in seasonal use ie farming or intermittent use in rural fire departments.  Not too different than many bus conversions. 

I know there is no real difference in construction and maybe it is my subconscious saying use something easier on my back,  but a few smaller batts are the way to go for me.  The only drawback is more connections to maintain.

I have a rarely used International day cab with a Cummins 350BC that had 4 group 31s.  Over the years as they died I removed one at a time and even thought they were old, when I got down to one, it would still start it if warm out or heated.  I start the 4107 when warm or heated with one Optima.  It starts on the first turn.  New batteries will wait until it is ready to hit the road. 

Don 4107

[Hartley]

Group 31's are much easier on the back and hernias than any 4D or 8D battery.

I placed 4 group 31's in my MC9 back in 2005 and have not been sorry at all.

In fact I get better cranking than I did with a pair of new 8D's that I took out.

1400 amps divided by 2 is 750 CCA total on a good day. Slow roll to start big engine.

2 sets of group 31's setup series/parallel for the 24 volts spins the engine over twice as fast and longer especially in colder weather.