Can I use 2 Car batteries instead of marine?

bawla47

Cadet
Joined
Dec 1, 2004
Messages
23
ive got 2 new car batteries in a boat i just bought. its a 1978 grady white marlin 201. Would i be able to use those and be alright? (someone said it needs to be sealed, and salt and destroy it quickly) hence i definatleyt without a doubt need marine batteries. Im tryin to save every little i can, but if its a must, then ill have to buy them. What do you guys think?<br /><br />Thanks in advance. <br />Jay D
 

redmopar

Seaman
Joined
Nov 30, 2004
Messages
58
Re: Can I use 2 Car batteries instead of marine?

Never used a marine battery for my cracking battery. I have a cranking battery I swap between one of our tractors and the boat and usually get 5+ years out of the $46 walmart battery I use. Nothing special about it, its the same model I use in my trucks. Never had a corrosion problem dispite the salt. I find switching the battery around frequently extends its life because it gets used more often. ;)
 

18rabbit

Captain
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Nov 14, 2003
Messages
3,202
Re: Can I use 2 Car batteries instead of marine?

Hi Jay...welcome to the board! :) <br /><br />12vdc is 12vdc no matter where it comes from. A car/truck battery will work just fine. Obviously, bat size is a consideration. The primary difference between car and boat starting bats is the internal support of the lead plates. bigger bats have a difference in case design, too. Marine bats are designed for an abusive environment...possibility of lots of vibration. Several folks on this board use car bats for starting and have never had a problem in a billion years. If you have additional accessories hanging off the bat you might want to consider a dual use (starting/deep cycle) but that is even more money. If you are heading offshore I would highly recommend marine batteries.<br /><br />Btw, there are some rules for the use of a battery onboard a boat. Whatever bat you use, you gotta follow the rules (strapped down, non-conductive cover, etc).
 

Luna Sea

Lieutenant Junior Grade
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May 20, 2002
Messages
1,069
Re: Can I use 2 Car batteries instead of marine?

If you already have them, use them. But the plates in a marine battery can withstand more abuse the way they're set up. Are you planning to beat the hull to death? I doubt it. Marine battery's can tumble around a little more, that's all. Just upgrade one at a time. You'll want one "deep cycle" on board anyways once you start using 12 volt toys. Good Luck. Love them Gradys!!
 

18rabbit

Captain
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Nov 14, 2003
Messages
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Re: Can I use 2 Car batteries instead of marine?

Yeah…what Luna Sea said :D ... plus the soup that is in any flooded bat is basically sulfuric acid. Not something you want splashing about. If the bat’s container will keep H2SO4 in (it does), it will also keep salt water out.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Can I use 2 Car batteries instead of marine?

Howdy, Jay.<br /><br />Welcome to iboats. :) <br /><br />Well, blah bla bla bla.<br /><br />Yes.<br /><br />Blah bla bla bla.<br /><br />Good luck. :)
 

bawla47

Cadet
Joined
Dec 1, 2004
Messages
23
Re: Can I use 2 Car batteries instead of marine?

thanks for all the help guys, i apreciate the input, Im glad to be part of Iboats now, seems like alot of good people are part of this board. <br /><br /> :)
 

18rabbit

Captain
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Nov 14, 2003
Messages
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Re: Can I use 2 Car batteries instead of marine?

You probably can't tell but JB is the brains of this operation. :D :D :D
 

tomatolord

Chief Petty Officer
Joined
Oct 1, 2004
Messages
548
Re: Can I use 2 Car batteries instead of marine?

After reading all the posts about batteries I have come to this conclusion...<br /><br />Deep cycle - use it to run the electronics, but to not be the primary starting battery<br /><br />These MAY not supply enough amps to start - these batteries were primarily designed to last a long time and be drained very low and then recharged<br /><br />Car battery type - Primary Starter <br /><br />Designed, to provide high amps for a short period of time and to be quickly recharged,<br />they are not designed to be deeply discharged<br /><br />Now if you use a car battery to do these things it will work fine, it just will not last as long as advertised.<br /><br />The issues also applied to the vibration and water, car batteries are designed to sit in a nice warm environment, with little or no load on them<br /><br />Some of these guys go way offshore and really need to have their batteries work. Pretty much the batteries are weak link in boating<br /><br />It does not mean that the correct battery wont leave you stranded, it is just less likely to.<br /><br />and welcome!
 

18rabbit

Captain
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Nov 14, 2003
Messages
3,202
Re: Can I use 2 Car batteries instead of marine?

Oh-oh! We’re in trouble...someone is actually reading what we write?!?!? :D <br /><br />Tomato Lord - you pretty much got it. It’s also worth reading the stuff about charging systems to maintain the batteries. ;)
 

radsrh

Petty Officer 1st Class
Joined
Oct 30, 2002
Messages
250
Re: Can I use 2 Car batteries instead of marine?

A car battery in a nice warm environment? -30 under the hood of my truck parked outside :confused:
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Can I use 2 Car batteries instead of marine?

Actualy Heat probably kills more batteries than cold. Ever notice your car battery is away from the heat and in front of the engine. <br /><br />I have run 1 group 24 auto starting battery and one group 24 RV/Marine deep cycle since my boat was new in 1980. Never had a battery that did not last 6 years or more. Batteries should be near the stern of the boat and be in a battery box and strapped down. At least they should have the positive terminal completely covered to prevent anything from hitting postive post and causeing a spark. My deep cycle starts my little 3.0L with no problem even with all the gear on and the blower.<br /><br />TO make your batteries last never discharge a starting battery below 80 percent or a deep cycle below 50 percent. Make sure both batteries get fully charged and not over charged. I use a battery isolator on the boat and a 10 amp automatic charger at home that charges both batteries thru my battery isolator. Charge your batteries at least once a month year round weather you use your boat or not. If they have vent caps keep battery filled to proper level with distilled water. Any time you add water charge the battery also. Put some load on them and test before your long trip off shore but make sure you recharge. Leaving a battery discharge will do damage. Over charging will do damage. Do not charge with a manual charger (even a 2 amp) if you are not going keep a close eye on the battery and shut off when charged. I reccomend useing manual charger only for boat anchor or land fill.
 

redmopar

Seaman
Joined
Nov 30, 2004
Messages
58
Re: Can I use 2 Car batteries instead of marine?

I agree with Boatist's manual charger comment. A good automatic charger is less than $40. How much does that deep cycle cost??? Ya wanna toast it?
 

swist

Senior Chief Petty Officer
Joined
Jul 1, 2004
Messages
678
Re: Can I use 2 Car batteries instead of marine?

I know starting batteries for cars and boats should be about the same animal, except for some additional rigidity, as has been mentioned in this topic, but my experience is that a deep discharge of most car batteries is a death knell - yeah you jump them and they recharge but you may have taken a big chunk off its life, in my experience. I've accidentally run boat starting batteries down to zilch on a number of occasions but they seem to take it more.<br /><br />On the other hand, this may be very brand or environment dependent. I certainly can't claim I have documented records.<br /><br />These days I use combination starting/deep cycle (two of them). Just the Boat/US house brand, whatever that is (Exide?), and I'm pretty impressed. I am replacing a pair after 10 years of service - but more as preventative maintenance then because of any indication that they are failing (I don't want to find out their limit is 10 yrs and 1 day when 20 miles offshore). The house brand combo batteries are not expensive - I think these were something like $75 each (series 24) but that was 10 years ago of course.
 

ThomWV

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Dec 19, 2003
Messages
701
Re: Can I use 2 Car batteries instead of marine?

Folks, you all should have read his post a little more carefully.<br /><br />He said he is running these batterys in a '78 Grady Marlin 201. Have you ever ridden in an older Grady? <br /><br />Putting a set of batterys in one of those hulls is not like the soft ride from putting them under the hood of an Impala, or even a Blazer for that matter. That is a hard riding hull that will beat a battery to death.<br /><br />I've had one battery fail from a broken loose plate in a car and 3 of them do it in boats over the years. Two of them died in my current boat. That was with marine batterys. My boat, which will beat you to absolute death after a full day off shore, rides just a bit softer than one of those Grady's too.<br /><br />So while in general many boats, particularly those that never venture from calm waters, can use automotive batterys without a problem at least in that hull I'd go marine if I were you.<br /><br />Also, just to keep straight on this. There is no task that is performed by a typical automotive style battery, including starting, that can not be performed equally as well or better by a deep cycle battery.<br /><br />Thom
 

jlinder

Lieutenant Junior Grade
Joined
Jul 5, 2004
Messages
1,086
Re: Can I use 2 Car batteries instead of marine?

Has anyone ever tried shock mounting the battery case to soften the blows a little? <br /><br />Not sure how you could do it and still have a secure mounting, but it might be interesting.<br /><br />(Maybe a rubber pad under and around the battery?)
 

Bondo

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Apr 17, 2002
Messages
71,095
Re: Can I use 2 Car batteries instead of marine?

Originally posted by JB:<br /> Howdy, Jay.<br /><br />Welcome to iboats. :) <br /><br />Well, blah bla bla bla.<br /><br />Yes.<br /><br />Blah bla bla bla.<br /><br />Good luck. :)
JB,<br />This thread is about Batteries.........<br /><br />Not Oil.................................... :D <br /><br />Good Info, none the less.......
 

Darrendude

Petty Officer 2nd Class
Joined
Nov 16, 2004
Messages
145
Re: Can I use 2 Car batteries instead of marine?

Jack<br /><br />That would be a good idea I would think. I think I am going to pad my 2 deepcycle batteries that are under my bow casting deck.
 
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