New Start Battery?

Jun 1, 2007
257
O'Day 322 Mt.Sinai
Replacing my 2 Group 31 general purpose batteries on my O'Day 322, w/2GM20F engine. All LED interior lights, planning on adding a 12VDC TV, and an Isotherm Compact Classic 2501 refrigeration unit. No plans for much else electric. Have an 80 amp, external regulated alternator, and adding about 125W solar panel. Have a Blue Sea ACR.
So....
I'm getting a Trojan T1275 house battery, but my question is the start battery. Any recommendations? Do I need to tailor the start battery to the house battery?
 

Blitz

.
Jul 10, 2007
613
Seidelmann 34 Atlantic Highlands, NJ
ouch, 85 lbs for the T1275.

be sure the height fits where you are putting them.

if your start battery is going to be connected through an ACR be sure it's flooded as well. I would just get a group 24 or 27 deep cycle so it can be used as backup to the T 1275 monster.
 

Tom J

.
Sep 30, 2008
2,092
Catalina 310 Quincy, MA
No need to tailor the start battery to the house battery as long as they are the same type. I have 4 golf cart batteries for house, and a 12v start battery for the engine.
 

Blitz

.
Jul 10, 2007
613
Seidelmann 34 Atlantic Highlands, NJ
you should clarify what you plan on doing with it, cruising or day trips, etc

also if you are normally at slip or mooring.

do you have an AC charger?
 
Oct 22, 2014
16,409
CAL 35 Cruiser moored EVERETT WA
Ah Mickstr. It is winter and you have been cooped up with Covid. Saving all sorts of money and now you need to spend it. I get it.

Nice battery. 12 volts 150 AHr. 82 pounds.
Cost about $233 online plus shipping. Minimum 4

What ever you do look at the whole system. Spend money frugally. The TV and the Refrigerator will eat into your battery system depending on how they are used. That 150 Amp hours really is only 75 AHrs of usable time. 2 batteries at 160lbs (like adding another crew member who sits there) means 150 Ahrs of available power.

I refer you to the expert on this subject. MaineSail
Here is his link that discusses the system. The Alternator and what you need to keep your new batteries preforming for more than a couple year. And the challenges of insufficient alternators in the system.

"What you need will depend largely on use, bank size and desired daily Ah consumption as well as battery chemistry type. You will also need to consider your maximum desired engine run time. If you only day sail, and tie to the dock every night with shore power charging, converting the factory alternator, to a higher performance model, will gain you little. This is why; it’s all about use."​
 
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Likes: LloydB
Jun 1, 2007
257
O'Day 322 Mt.Sinai
you should clarify what you plan on doing with it, cruising or day trips, etc

also if you are normally at slip or mooring.

do you have an AC charger?
Mooring, have an AC charger only when transiting at a marina. Day trips, a 3-5 day trip 1-3 times a summer...
 
Jun 1, 2007
257
O'Day 322 Mt.Sinai
Ah Mickstr. It is winter and you have been cooped up with Covid. Saving all sorts of money and now you need to spend it. I get it.

Nice battery. 12 volts 150 AHr. 82 pounds.
Cost about $233 online plus shipping. Minimum 4

What ever you do look at the whole system. Spend money frugally. The TV and the Refrigerator will eat into your battery system depending on how they are used. That 150 Amp hours really is only 75 AHrs of usable time. 2 batteries at 160lbs (like adding another crew member who sits there) means 150 Ahrs of available power.

I refer you to the expert on this subject. MaineSail
Here is his link that discusses the system. The Alternator and what you need to keep your new batteries preforming for more than a couple year. And the challenges of insufficient alternators in the system.

"What you need will depend largely on use, bank size and desired daily Ah consumption as well as battery chemistry type. You will also need to consider your maximum desired engine run time. If you only day sail, and tie to the dock every night with shore power charging, converting the factory alternator, to a higher performance model, will gain you little. This is why; it’s all about use."​
I bought the alternator and external regulator from MainSail.... I believe with the Trojan I'll be fine on the house side given my minimal needs, just wondering about the start. I'm thinking a Group 27 wet cell should be fine...
 
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Likes: jssailem
Apr 5, 2009
1,654
Catalina '88 C30 tr/bs Oak Harbor, WA
ouch, 85 lbs for the T1275...
That is a light-weight compared to my Lifeline 4D at 135lbs. I used the mainsheet on the cabin top winch to put it in. Probably going to do the same in the spring when I need to replace it.
 

CarlN

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Jan 4, 2009
578
Ketch 55 Bristol, RI
A group 27 standard car battery should be fine for a start battery for that small engine. No need for “ Marine” or deep cycle. Even a group 24 is probably fine and will save some space. Focus on CCA (Cold cranking amps). This is all about turning the starter briskly. 650-700 CCA should be plenty. To not lose amps in the wiring, be sure the cables are big enough with shiny ends. Put a good electrical grease on the terminals. My favorite is this. https://www.amazon.com/NO-OX-ID-Tube-Special-Grease-Compound/dp/B00HSW341A/ref=sr_1_7?crid=CB9PT0CCQK83&dchild=1&keywords=no+ox+id+electrical+grease&qid=1608636367&sprefix=No+ox+I,aps,204&sr=8-7
 
Last edited:
Apr 10, 2010
18
catalina 30 Dartmouth, nova scotia
Where are you getting your 12vdc tv? Have a 2002 310 hull 166. Have 65 amp alt on westerbeke m25 xpc with a sterling external regulator. Just a 650 CCA regular battery for starting, no problems. Have 100 watt solar panel with gensun controller. Hope to place 2 140 watt panels on the bimini for 2021 summer season here in Nova Scotia. Thanks for any info anyone can provide.