Starting Batteries (Engine only!)

[Eric Perplies]

Gregg,

I went through a similar analysis a couple of years ago. I wanted to
install the AGM's as my starting batteries so I could parallel them
with my house batteries to extend the time to drop below 50% state of
charge when dry camping. What I found was Detroit Diesel recommends a
minimum of 2700 CCA on the Series 60. I should have stopped my
analysis at that point because there are no AGM batteries that would
fit in my battery tray that would come close to 2700 CCA.

I then talked to LifeLine AGM battery people about how a certain size
AGM battery would do in a starting application. I explained to them
my ability to parallel the 4D house batteries with the engine starting
batteries.

LifeLine did not recommend using the AGM batteries paralleled with the
4D house batteries because of the significant difference in internal
resistance in the 4D and the other AGM battery I was considering.
That low internal resistance of the AGM starting battery would mean
that the loads would preferentially come from the smaller AGM starting
batteries. Additionally, I would tend to overcharge the low
resistance AGM starting batteries when running down the road, when I
cannot control the joining of the two banks of batteries.

Lead acid batteries have a much higher internal resistance. That
offers an advantage when charging the banks of batteries together and
when discharging them when paralleled with the house batteries. This
issue requires pages of discussion. Not a few sentences.

Another factor to keep in mind is that there is a drain on your
chassis batteries (as well as your house batteries) when parked.
(There is on mine anyway.) While you can isolate the house batteries
on your coach you cannot isolate the chassis batteries without tools.
You can verify this on your coach by lifting the ground terminals on
your engine starting batteries. Small sparks will fly. This
means that when parked for a long period you either want to physically
disconnect the engine starting batteries or better yet; leave the
coach plugged in.

Eric Perplies
currently in Littlerock, WA
96' 42' WBWL


--- In WanderlodgeForum@yahoogroups.com, "Gregg Kizer" wrote:
>
> GROUP Question:
>
> What batteries ("Deep Cycle" or "Regular Type/ with high CCA rating")
> are best for "Start Engine/ assignment duty" would one go with when
> replacing all three (3)battery units. It seems time has come to
> replace out the three (3) engine batteries of which are presently a
> Deep Cycle type (Wolverine Deep Cycle /brand of battery/ with
> ThermOil Battery Technology) when aquiring this coach . My other
> batteries (six Large Deep Cycle AGM) are AGM type for the "House
> Service". I have a splite system battery set up for this '96 coach.
>
> Does the various seating around of the coach while in storage (not
> using coach, cold winter storage, etc...) warrant and best suit
> the "Deep Cycle" type batteries vs the "Regular Type" for purpose of
> starting my 60 Series Detroit engine??? This might be the reason for
> the "Deep Cycle" type batteries on the "Engine" battery set-up that
> is being used now.
>
> Would the Sam's Club "COMMERCIAL" type battery (@ $87.24 per battery
> cost)= "31A 12V @ 950 CCA" work just as well and replace them often
> as needed or would one invest into the "AGM type Deep Cycle" type
> batteries for the over all perforamce and longivity due to the
> various storage assignments of the coach and various charging issues
> (cyles, engine charging, shore power/inverter-charger, etc.)?????
>
> It seems that Blue Bird has the engine battery bank charging
> controled by owner (me!!) to regulate the amount of engine battery
> bank charge while sitting (shore power or generator power) and not
> runing the engine (travel time) by design...
>
> NOTE: With price of fuel, I am sure all our batteries will be more
> in a directed storage stage of life of our coaches....Just a thougt!
>
> WHAT WOULD YOU GO WITH when needing replacements? I am sure
> the "ThermOil Battery Technology" was applied to the batteries to
> keep the corrision issue down in the battery compartment area vs. the
> AGM type batteries as used in "House battery Service"...
>
> Gregg Kizer
> `96 WBSD `42
> KB9BG (ham call)
> New Castle, IN
>