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Battery sizes

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I’m looking to replace my batteries. I’m not sure the correct batteries are in there since I’ve never been able to start with just the starting battery selected. 
 

Anyone know what size (Cold cranking amps etc) the starting and house batteries should be?

 

i have a 2005 256ssi with Volvo penta 8.1 gi-e

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I would see what the largest battery is that will fit in the spot where the starting battery goes and get it.  More CCA in same physical size means thinner plates, weaker battery.  Are you sure your starting battery is actually a starting battery and not a deep cycle?  Have all cables and connections been checked for corrosion?  Starter or starter solenoid could be the issue.  Interstate makes a whole lot more battery sizes than you will find at a place that sells them.  But you should be able to order them.

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Your going to want one with 1000cca for a starter. Second battery doesnt matter. Usually deep cycle and biggest you can hold. My guess is the factory starting tray is a group 24 size. Should say in the battery.

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Do you have & use a lot of loud music ?  a lot of the time ? Do you use dock power to recharge your batteries all the time ?

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Starting ability is related to CCA and MCA. Same current draw test conducted at different temperatures. 

Your engine manual will specify how many CCA are required for reliable starting. For an 8.1 I would expect that to be in the 650-800 CCA range minimum. More is always better. 

I prefer running Group 31 batteries as they are the largest you can get without going to 4D or 8D. Those 4D and 8D batteries are outright unwieldy and weigh over 100 lbs. Group 31s are perfect for all boats under 40’ or so. 

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A correctly  maintained & operating engine ......ALWAYS starts in 1 second ....or less .....of cranking.  Carb or F I.  There are NO  NO exceptions to that ability of a engine. I have used size 24 batteries with large V8s. RUUUMMPPP.   Every time.

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8.1 will want 800 cca which is around 1000 mca. Can get a group 24 that will meet that, but you really want larger. Most 27m6 Batteries will meet these specs, and a good group 31 will.

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3 hours ago, rjbergen said:

Starting ability is related to CCA and MCA. Same current draw test conducted at different temperatures. 

Your engine manual will specify how many CCA are required for reliable starting. For an 8.1 I would expect that to be in the 650-800 CCA range minimum. More is always better. 

I prefer running Group 31 batteries as they are the largest you can get without going to 4D or 8D. Those 4D and 8D batteries are outright unwieldy and weigh over 100 lbs. Group 31s are perfect for all boats under 40’ or so. 

Yep!

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The spec. sheet  for a 8.1 call out 660 amps cranking amps.  That is on the web page of the engine. So a 40 foot boat with a V6 engine needs a size # 31 battery ?

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WTF are you talking about.... AGAIN... An 8.1 is not a V6 and the size of the boat does not matter in the equation...

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My Merc 350 MAG/MPI requires 950 MCA. I use a group 24 that is rated 1000 MCA.  
The engine ECU needs to see sufficient voltage to start, so it is important to use a marine “starting” battery. A deep cycle Battery does not provide the short high amperage power required. Volvo engines are know to be very sensitive to correct voltage. 

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Phil

Lay off the sauce and read my postings completely.  Also Read the posts I am responding to. ......rjbergans post .  about size 31 batteries are perfect for all boats under 40'.

Take a reading comprehension course.  I stated 2 separate topics. You rolled it into 1 topic.   WTF is wrong with you ? 

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On 8/26/2020 at 5:50 PM, cyclops2 said:

The spec. sheet  for a 8.1 call out 660 amps cranking amps.  That is on the web page of the engine. So a 40 foot boat with a V6 engine needs a size # 31 battery ?

660 CCA is within the 650-800 CCA range I posted without looking anything up. 

I suggested a Group 31 as they are manageable by one person. How many batteries and what sizes is ultimate determined by your usage. Group 31s are great up to around 40' because you don't usually have room to move up to 4D or 8D on smaller boats. That's not even accounting for the extreme weight of 4D (~100 lbs.) and 8D (~125 lbs.). I would suggest a Group 31 for each engine and separate Group 31s for house batteries. On my 2006 Sig 330, there's only room for 3 Group 31s, so I have one for each engine and a house. It would be nice to add another Group 31 or two in parallel to increase the house bank capacity, but there's no where good to mount them.

As for the whole Volvo "Don't use AGM to start" statement, that's most likely driven by people replacing small Group 24 starting batteries with AGM deep cycle batteries. In that case, the new AGM battery would have far fewer CCA and cause problems. However, increasing the battery size will prevent those issues. I'm running a Duracell Group 31 AGM deep cycle that produces 800 CCA, which is sufficient for Volvo's 650 CCA spec.

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I am in need of a new battery. The battery being replaced is an Ever Start from Walmart. It is 5.5 years old. 675 MCA and group 24ms.  Is this ok?

When my engine is cold due to non-use it takes a lot of revolutions to get it started. Been like that from the beginning.

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I moved from a group 24 to a group 27 battery by simply removing one end of the battery tray. It still safely bolts into place.

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SST

Do you have carburetors ?  If yes the the fuel bowels are drying out from heat & time.My 5.0 crb is dry in a week of summer days.

I prefill them by turning on the key only for about 20 seconds.  That also sets the choke correctly. A click of the starter for 1 second. RRRUUMMPP. Mercruiser 5.0L

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2 hours ago, cyclops2 said:

SST

Do you have carburetors ?  If yes the the fuel bowels are drying out from heat & time.My 5.0 crb is dry in a week of summer days.

I prefill them by turning on the key only for about 20 seconds.  That also sets the choke correctly. A click of the starter for 1 second. RRRUUMMPP. Mercruiser 5.0L

Thanks, I'll try that when she goes back into the water next week.   4 barrel carb.

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Also check if the choke is closed too tightly during a cold engine start.  People love to experiment with all the screws on a carburetor. Including the choke setting. Cold and hot . Most are electrical that open with time & power from the IGNITION    ON   position.  See a problem with the 20 second priming time ??  It can cause the choke to move to a LESS CHOKING position too quickly.   Solution   I turn the key  ON  FIRST THING as I enter the boat.  If it starts up great.  If not. 2 back ups. Key goes right to   OFF for a couple of minutes. Starts right up. .............Or I pump the throttle lever  2 times.  Then try to start. Starts right up.    .............Both ways add raw fuel to give a cold rich enough mixture to start up. ...........After about 2 minutes. I stop the engine.  Then test for a instant re start. done.  Test is the next morning.........Turn key on then go right to the starter position. It starts in  1 second.

Who ever fiddles with a choke can RUIN the cold starting EASE of it............ If you feel smothered firing & black smoke above the prop ?  The choke is either damaged or adjusted incorrectly.  Adjustment is easy to do.

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Funny thing happened on the way to get a new battery.  I decided to get a group 24 starter batter rated at 1000MCA's.  I asked the salesman if I needed to charge it. He said the battery should be around 80%.  The next day I put it on my charger to "top it off" and the charger shows 9% at 10v. Hmmmmm, isn't that dead?  The sticker on the battery said 7/20. New.  So I continue to charge it. Slowly it makes its way....10, 20, 30....62%.  It wouldn't charge beyond 62% and then the charger indicates..."BAD." I call back and discuss this. They say bring it back and we'll test it to make sure MY CHARGER is not giving out false info. They tested it. 0% and 11.93v.  DEAD!  Of course they don't have another in stock...another battery was put on order. I might see the batter around the 6th of Sept.  Gee, Labor Day is over by then.

I didn't realize getting a new battery was so complex!  GRRRRRRRRR  

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Take a battery from somebodies  2nd or 3rd car for the holiday. They could give you a Loaner ?  Buy from some other chain store.  Bring your meter to save time.

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I do have a deep cycle battery in the boat. It is not hooked into the system and is only used for a secondary bilge pump. It does not receive charge. Its an old battery. Time is flying faster than I ever thought. This battery is 12 years old. It is still holding a charge. Not perfect but more than expected. I tested it and it was at something like 80% at 12v. That is two months since it last received a charge. 

The salesman called me the other day and left a msg. They say something is wrong with my charger. They were able to put a full charge on it. But I just returned the call and the manager said the battery was dead but was able to put full charge on it. So that means, to me anyways, the battery has failed twice. I told him I have no confidence in the battery and I want a new one. He said ok but kept insisting that my charger is to blame. If the test meter and the charger are in agreement, that hardly seems to me that my charger is the issue. 

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