Two Deep Cycle Batteries?

[Beefer]

For some reason, I thought I had one Starting battery, and one deep cycle, but tonight I found out that both of my batteries are deep cycle. Previous owner put them in. Is this ok, or should I really have one starting, and one deep? The engine is a 4 cyl MC I/O, and I've noticed somewhat slow starting. Could this be because of the lack of a higher CCA starting battery?

 

[BaileysBoat]

Re: Two Deep Cycle Batteries?

Most deep cycle marine batterys are hybrids. Should be fine in good condition. Depends on the cranking amp rating.

 

[Beefer]

Re: Two Deep Cycle Batteries?

Most deep cycle marine batterys are hybrids. Should be fine in good condition. Depends on the cranking amp rating.

Just checked, they're both 500CCA

 

[BaileysBoat]

Re: Two Deep Cycle Batteries?

Should be fine. Have them load tested.

 

[captain zac]

Re: Two Deep Cycle Batteries?

Merc requires that you use a cranking bat on there engines
should be in your Manufactures/installers manual
They also require that you not run the engine with the bat switch in the Both or All position

Harry

 

[Jerryh3]

Re: Two Deep Cycle Batteries?

I looked in my manual it only states a minimum MCA, not battery type.

 

[captain zac]

Re: Two Deep Cycle Batteries?

Jerry

Are you looking in the installation Manual
EFI's and MPI's it is a must
although the deep cycle would crank it over its not what the bat was designed for

 

[Jerryh3]

Re: Two Deep Cycle Batteries?

Jerry

Are you looking in the installation Manual
EFI's and MPI's it is a must
although the deep cycle would crank it over its not what the bat was designed for

I looked in the service manual, but I'll check in the install manual if I can find it. Mine is just a 2 bbl, so it may not have been spec'ed.

 

[dingbat]

Re: Two Deep Cycle Batteries?

Jerry

Are you looking in the installation Manual
EFI's and MPI's it is a must
although the deep cycle would crank it over its not what the bat was designed for

No mention of battery type
http://www.perfprotech.com/store/articles/mercruiser-battery-cable-requirements.aspx

 

[captain zac]

Re: Two Deep Cycle Batteries?

Please read again
at the top of the chart it says




Engine(Cyl./Type)
cid (l)
Minimum Required Cranking Battery Size

V6 EFI
262 (4.3L)
550 cca/700 mca/120 Ah

V6 Carb
262 (4.3L)
375 cca/475 mca/90 Ah

V8 Carb
305 (5.0L)
375 cca/475 mca/90 Ah

V8 Carb
350 (5.7L)
375 cca/475 mca/90 Ah

V8 MPI
350 (5.7L)
550 cca/700 mca/120 Ah

V8 MPI
454/502 (7.4L/8.2L)
650 cca/825 mca/150 Ah

 

[dingbat]

Re: Two Deep Cycle Batteries?

Please read again
at the top of the chart it says




Engine(Cyl./Type)
cid (l)
Minimum Required Cranking Battery Size

V6 EFI
262 (4.3L)
550 cca/700 mca/120 Ah

V6 Carb
262 (4.3L)
375 cca/475 mca/90 Ah

V8 Carb
305 (5.0L)
375 cca/475 mca/90 Ah

V8 Carb
350 (5.7L)
375 cca/475 mca/90 Ah

V8 MPI
350 (5.7L)
550 cca/700 mca/120 Ah

V8 MPI
454/502 (7.4L/8.2L)
650 cca/825 mca/150 Ah

You?re making the assumption that they are using the term "cranking battery" literally. How else would you describe a battery used to ?crank? the motor? One would have to wonder why they give a AH rating which is typically reserved for a deep cycle battery.

If there was technical reason not to use a deep cycle battery they would have cautioned against their use.

 

[captain zac]

Re: Two Deep Cycle Batteries?

No assumption
If you look at the specs on the chart for Cranking Batteries you will see that it will give you a cold cranking anps, marine cranking amps, and some times Hot cranking amps.
If you look at the specs on a deep cycle battery you will see Amp Hour Capacity, and recovery time. Nothing about cranking unless it is a dual purpose battery
One of the reasons that it is important that a cranking bat is used is it can be charged very quickly
example
first start of the day run to your destination and your alt. recharges the cranking battery on your way to your destination
the bat is now topped off
switch to a deep cycle and troll, radio, fish finder ect.
I can run this bat until its dead and know that I can still start the engine.
The deep cycle takes alot longer to recharge and in most cases requires a charger and AC power the alt. just can not supply enough amps

 

[Silvertip]

Re: Two Deep Cycle Batteries?

Nonsense! I suggest you take a gander at the following chart from U.S. Battery. You will see their deep cycle batteries carry MCA ratings.

http://www.usbattery.com/usb_specs_deep_cycly.html

Nonsense also that the alternator can't supply enough amps to charge a deep cycle. Even the smallest I/O has a 60 amp alternator. A deep cycle battery can be safely charged at 20% of its capacity so the engine alternator has more than enough to charge it. In fact you can run on the BOTH setting with no problem whatsoever. The voltage regulator monitors "system" voltage and cannot detect the state of one battery over the other or if there are one, two, or a dozen batteries in parallel. If you drew down the deep cycle and then switched to BOTH without starting the engine, both batteries would equalize in a relatively short period of time. On the other hand, if you were trying to keep two batteries topped off with a 12 amp alternator on a small outboard, yes, you would have to run wide open for many hours to do so. I agree with Dingbat that the term "cranking battery" in the chart is simply that -- it means the battery you use to crank the engine. Doesn't matter what "type" of battery this is as long as it has the required cranking power. And yes -- deep cycle batteries sometimes do also include CCA or MCA or both as the referenced chart shows. Lastly, a deep cycle battery does not have a "recovery time spec" but it does have a "Reserve Minutes = xxx @ 23 amps (some spec @25 amps).

 

[captain zac]

Re: Two Deep Cycle Batteries?

Per Merc.

The chart is for Cranking Batteries only
If you decide to use a dual purpose deep cycle for cranking then you would need 20% more cranking amps than in the chart

 

[Jerryh3]

Re: Two Deep Cycle Batteries?

No assumption
If you look at the specs on the chart for Cranking Batteries you will see that it will give you a cold cranking anps, marine cranking amps, and some times Hot cranking amps.
If you look at the specs on a deep cycle battery you will see Amp Hour Capacity, and recovery time. Nothing about cranking unless it is a dual purpose battery
One of the reasons that it is important that a cranking bat is used is it can be charged very quickly
example
first start of the day run to your destination and your alt. recharges the cranking battery on your way to your destination
the bat is now topped off
switch to a deep cycle and troll, radio, fish finder ect.
I can run this bat until its dead and know that I can still start the engine.
The deep cycle takes alot longer to recharge and in most cases requires a charger and AC power the alt. just can not supply enough amps

Both of my deep cycle batteries call out the CCA right on the front of them.

 

[1980Galaxy]

Re: Two Deep Cycle Batteries?

I don't think you will have a problem but I would get a cranking battery next time. A deep cycle will still start your engine tho, just not made for that purpose.

 

[captain zac]

Re: Two Deep Cycle Batteries?

Jerry

Yes

Those are dual purpose bats.
a good pick for smaller boats that when on the hook only run a radio
but the original post was a two bat. system and was haveing trouble with slow starts
A starter bat and a deep cycle would correct that problem
buy a starter par. the two deep cycle for more life on the hook.
Start on the starter bat #1 run to the hook on #1 on the hook switch to #2
on the return start on #1 run home on #1 at the dock or on the trailer switch to OFF
recharge with the proper charger at the dock or at home if on the trailer
will never have a starting problem

 

[Jerryh3]

Re: Two Deep Cycle Batteries?

Jerry

Yes

Those are dual purpose bats.
a good pick for smaller boats that when on the hook only run a radio
but the original post was a two bat. system and was haveing trouble with slow starts
A starter bat and a deep cycle would correct that problem
buy a starter par. the two deep cycle for more life on the hook.
Start on the starter bat #1 run to the hook on #1 on the hook switch to #2
on the return start on #1 run home on #1 at the dock or on the trailer switch to OFF
recharge with the proper charger at the dock or at home if on the trailer
will never have a starting problem

If you say so.

 

[bruceb58]

Re: Two Deep Cycle Batteries?

I use deep cycle batteries to start a carbed 7.4L V8 engine. The OP should not have a problem with a carbed 4cyl.

If the starting is slow its because of other reasons than the type of battery he is using.

 

[Beefer]

Re: Two Deep Cycle Batteries?