batteries again 8D ?????

[Lonnie time to go]

I need a little help with this
some have said that a good battery is the lifetime 8D31  sealed battery no maintenance.
well I found 8D  batteries  with the label   908D  400amp reserve  1400 CCA {not exact}
price wow 225.00 no lifetime  only 1 year
Wondering how to find correct battery  with lifetime  at what cost and price and brand
I want batteries to start the bus only cant afford house batteries at the current time
another would be when I do buy house batteries  do I have to buy new starter batteries.
thanks for the help

[Lonnie time to go]

Forgot to add that I am in michigan very cold winters.

[Blacksheep]

Personally I would ditch the 8D's, go with group 31's as long as your JUST using them for starting, and seeing as how your in the cold climate, go with a block heater!

BS

[tekebird]

search the past posts, I had a nice head to head comparison of 31 vs 8d.

really the benefit of the 31 is that they are lighter...

Nothing beats a pair of 8D's for starting in Northern places.

[tekebird]

Volume of batteries

Grp 31  approx 835 CI
8D                   2296 CI

so basically it takes just shy of 3 Grp 31's to give equal performance of 1 8D

Optimum Operating temp for lead acid batteries is about 77 degrees (OATS)

In a perfectly new battery you lose roughly 10% of it's capacity for ever 10 degrees of temp decline

this is why some people start having cold start issues when it's not really cold out.

between cold soaking the block overnight and cold soaking the batteries themselves this effect can be magnified

some other stats to save you from looking them up.

31 900CCA, RC 195, # of plates 120 (max)
8d 1400CCA, RC 380, # of plates 180 ( max)

RC=reserve capacity is in minutes and is based on a 25amp draw

[tekebird]

My money and coach.....in Michigan, a pair of 8D's.

the block heater is a given no mater the battery configuration

A couple crank no starts will do in a pair or three of 31's fairly easy in sub freezing temps

[Hartley]

When buying start & running batteries I always look at them this way.

Starting batteries should last at least 2 years. Spending lots of money on fancy
batteries just used for starting is a waste. If you get more life from them then
that's great. I do as do most people.

A pair of Truck/Fleet style 8D batteries with 1400 CCA is nice when you have cold
weather or hard starts. They are not cheap but not as expensive as sealed batteries and when you accidentally melt one or both the wallet impact is less.

I pulled the 2 8D batteries from my MC9 and installed 4 group 31 batteries all rated at 1050 CCA in the series/parallel setup for 24 volts.

Before I changed my start ups were normal and when colder weather came along somewhat harder to get the detroit spun over. That was with the 8D's inline.

Since I changed to Group 31 batteries, My starts are 3X faster than before and the low temp starts are much improved.

So much improved that It started another minor problem. The engine was spinning to life so fast that the fuel pressure sense switch would cut the starter off before the engine would catch and run. Had to adjust that. ( I know that probably didn't make sense. Sorry.. Just me lately. )

If you can't SPIN that detroit hard and fast it will become a chore to live with during less than ideal weather. Having a lot of reserve capacity is really nice if you get stuck having to reprime the fuel system and need a few extra start cycles to make stuff work.

Dave.....

[rcbishop]

Teke.....are U sure about those numbers???  I have not seen HDs with more than 1425+_...( per battery)  tell us where you get them...  Maybe it is something ...uh, new?

RCB

[tekebird]

rcb I think you are reading the data wrong.

CI is Cubic Inches of Volume/Lead

[tekebird]

Dr Dave,

not really a far comparison on your setups. unless your 8D setup wwere new batteries too.

[Sojourner]

I am from Michigan until Dec of 1999. I got tired of slow cranking worn out 8D batteries. I brought 2 new Sam's Club group 31 with about 1000 CCA. It cranks faster than before. When 15°F outside...it still cranks but need block heater on for about 45 minutes and then it rrrruuuuum just as soon I hit starter button.

Do what you want spend. The 8D are more for buses that have heavy duty air conditioner and interior lighting while idling. They too heavy to R&R to service & clean storage compartment floor. The warranties are not as good as group 31. Not many want to stock them due to slow mover. Back injury is usually from heavy lifting as well smashing finger or fingers.

If you're in below zero climate and wants to start it allot, then go for 4 of group 31 that rated at least 940 CCA. All newer heavy duty class 8 trucks are using 4 (some may be 2) group 31 batteries.

BTW...you can warm up 2 group 31 batteries quicker then 1 8D if need to in very cold climate.

FWIW

Sojourn for Christ, Jerry

[Lonnie time to go]

hi guys i was reading old post last night to get up to speed of battery
so  8D  and 31s are two different types thanks

[Hartley]

Dr Dave,

not really a far comparison on your setups. unless your 8D setup wwere new batteries too.

Unless I had already nearly given myself a hernia installing a pair of NEW 8D's
the week previously....
I was having issues with the side terminal versus the
top terminal battery styles. NJT used the side terminal and those are not
normally available at most truck battery places.

So while thinking things over I decided to pull the 8D's and go with the Group 31's
and not have to worry over post type crappy terminals and having to adapt
everything. A few heavy jumpers and 4 batteries and no corrosion problems.

The no-spill/fill Group 31's may have cost a bit more but so far they have held up very well even under non-ideal conditions.

[lostagain]

My coach was set up by the PO with a switch that connects the house batt. bank to the start batts. in case your start batts. are weak. That is really nice. Unless the house bank is depleted from dry camping for 4 days... I have been using that feature lately because my 8Ds start are tired and I'm shopping around for my best deal on 2 new group 31s.

JC

[jjrbus]

It would seem that Michigan is the problem. Most in the south and many northerners are useing group 31's. So maybe better leave Michigan and head south to solve problem.