Battery Banks 101~ I want to know

ok there is another battery thread going but i think this question fits here better
when you guys talk about setting up your battery banks some of above posts refer to having a starting battery,25, and a deep cycle,d31m for house
after reading all the optima matieral the say the the deep cycle, d-31m, will work fine for a starting battery as well.
are you just looking to save the cost difference of the starting battery compaired to the more expensive deep cycle?
is there a reason you could'nt use 2 d-31m's and alternate them day to day so you still have a fresh one for starting?(would be charging house battery used each day by starting engine and charging. if using refrigerator will this be hard on engine charging system using to keep batterys charged each day?
two questions there
 
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Starting and house batteries are examples of two extremes of battery usage. Sure any type will serve both purposes but ideally a starting battery needs to provide a large amount of current for a short period of time to crank the engine and a house battery provides a slow, steady current for a long period of time for accessory loads. Optimas are more ideal by design as a starting battery and the heavy plate flooded batteries like Trojans and others are your best house battery values. I wouldn't choose either for both purposes.
 
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Sorrento, don't you have that backwards?

Typically, a flooded cell battery is a starting battery.
AGM is usually dual purpose
Gel is typically deep cycle... "house" type battery

of course there are many more types... but none as typical as those three listed.
 
I'm a newbie, to the thread and boating as well. I discovered this thread while googling batteries for my 290 Sundancer. Not sure if this would be considered new thread material so I am postinng here.

The boat is a '98 w/ twin 4.3L's, Alpha 1 Gen 2 O/D's, a kohler generator and pretty much everything else except for a windlass.

I tried to answer my questions using the boat manuals and am still unsure what to do so I'm posting here.

The boat has 3 batteries, all Group 27. 2 are in parallel 1 is not. The 2 parallel batteries are dead (reading 8 volts w/ mulitmeter). I think this was my fault as I failed to check the water level in them until it was too late. In any case, since it would appear I have to purchase batteries I am trying to determine what the best option is.

I haven't been able to determine how the DC is aligned for house loads. I have two "Cabin" breakers, one on each main DC panel.

My questions are:
1. how do I determine what each battery really does (starts engine, or generator or house power)

2. what type battery should I look for (typical use is anchored for the day w/ radio and refrigerator on although refrigerator not necessary and occasional head use).

Thanks.
 
Did you get the answers you were looking for?
 
My batteries are 4 years old and I need to replce by Friday since I'll be on the hook for 4 days. My first thought was to just get 4 new dual type but after reading through this old thread I am wondering if I should get 3 dual types and one deep cycle for the house. What I did read is the port engine and house are parallel so they need to be the same type of battery?

Also, Is it OK to have different battery types on the same charging system?
 
I know this was an old thread that was re-opened but..........

Does anyone know of any good diagrams that will show how the batteries and switches need to be connected.

My boat has 3 batteries and 2 switches. 1 battery is dead so im removing it for now.
All 3 batteries were starting batteries (no idea why it was setup that way) but i want to have a dedicated battery for starting and a second bank for a house battery. Can you have a starting battery and a deep cycle battery on the same bank??
 
CAGE RATTLER said:
I know this was an old thread that was re-opened but..........

Does anyone know of any good diagrams that will show how the batteries and switches need to be connected.

My boat has 3 batteries and 2 switches. 1 battery is dead so im removing it for now.
All 3 batteries were starting batteries (no idea why it was setup that way) but i want to have a dedicated battery for starting and a second bank for a house battery. Can you have a starting battery and a deep cycle battery on the same bank??
Click to expand...

I'm wondering the same thing. A good diagram or site or manual would be helpfull. Our 260 has two banks (single starting battery & two deep cycle house batteries) that are charged seperately while on shore power (with the exact charger discussed earlier) but when underway can be set on 1, 2 or both.

It is my understanding that within each bank of batteries, they need to be the same otherwise they won't charge correctly since the charger/alternator isn't smart enough to tell that one is a regular and the other is a deep cycle.

There was discussion in the old part of the post about an isolator. While underway does the Guest switch not "isolate" the banks as long as it is on "1" or "2" and not "both"? Or am I not understanding this whole mysterious electricty thing?

CageRattler - what do you mean when you say you have two switches?
 
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