car battery vs "marine" battery for starting boat motor

[Hoffer]

Hey guys-

Here is probably a simple question - but I just dont know much about this stuff!

Is there any reason why you would have to use a "marine" starting battery for your outboard starting battery?

Can a regular car battery work OK??

I have a newer car starting battery that I have no current use for. I am in the market to buy a new starting battery for my boat...can I use the car battery - or do I need a marine starting battery??

Thanks for the info!

[BobT]

Car battery may work fine. About the only thing I can think of is that most boats, to my knowledge anyway, use the outboard starting battery to power the console, bilge pump, livewell, lights and such. A car battery, which is JUST a starting battery, may not be too friendly powering all these other things. It will work but the battery life may drop to some degree.

If I'm correct on this, a marine starting battery is usually a dual-purpose battery having the ability to handle the slow steady draw from lights and livewell pumps but also can deliver the amperage when your outboard demands it.

Bob

[Jordyn Kaufer]

I'd go with a marine battery because in our boat that we bought, it had a car starting battery and that didn't last to long when running all the electronics...

[tednugefan]

id go for the marine battery. car batteries are made for short bursts of energy to start a car, not to keep running for hours, where as a marine battery is made to keep running

[Surface Tension]

If your only going to use it to start your outboard then yes you can use it. However you might have different style posts.

[Phred52]

Hoffer, Besides all that's been stated so far, I've been told that the marine battery is better constructed to withstand the pounding of marine use. I guess it's a better mounting system for the plates or more space between them. Just so they don't short out as easily. For what it's worth. Phred52

[Hoffer]

Hey thanks guys...my new boat has the batteries - one up fron for the troller, one in the back for all the accessories like the lights, bilge, aerator etc....and then one in the back that just has the leads for the engine.

Even though just the engine is hooked up to this battery it sounds to me that it would just be safer to buy a marine starter.

Its just that I have bad luck with boat batteries! It seems like every year I have to buy a new one. I priced out some today and will go with one from one of the "battery stores" - it is a 24 month for about 70 bucks....

I also need to buy a new deep cycle battery for the accessories and I would love to go with one of those "6 pack" looking ones - but cant afford the 200 bucks at this time!

By the way, is there any way to tell if an older battery will hold a good charge? Lets say you charge it and then put a battery tester on it - and it says it has 100%. But does that mean it is still good? Will it just say 100% because it was just charged and then when you start to use it...just drain right down quick? How can you tell?

[sparkydm]

you should take it to an auto parts store to have it load tested. Some stores have these. It puts a load on the battery and measures it's condition that way.

[Surface Tension]

You know I've heard the same thing.

"A boat battery is made to take a pounding".

I don't know about that, Any battery that can take the pounding mounted on my my truck for 10 years can't be all bad.

I'll say one thing that is TRUE.

I starting battery will die a very early age if used for long slow draws.

[BobT]

Frank is right on that. A car battery is specifically designed to deliver very high current for short bursts. This makes it ideal for starting your car, boat, or whatever. It also prefers to be recharged in like manner. An engine starting battery really hates to be left in a partial or low charge state for any length of time.

A deep cycle battery is specifically designed for delivering low current power over longer periods. This makes them ideal for electric trolling motors and other electronics. They also prefer to be recharged in like manner but similar to engine starting batteries, it is not recommended to leave them in a low charge state for any length of time. Best to get them on the charger as soon as possible.

Dual-purpose batteries have some characteristics of both types. These are better suited for most marine starting applications where the battery is used to run lights, console, etc. but is also assigned the task of starting the outboard.

Using the wrong type of battery for the intended purpose will work but you can also expect a shortened life span. Neither battery likes to be discharged too deeply either so if you have a tendancy to drain your batteries till nearly dead, it'll take its toll on the battery's life.

Recharge your batteries as soon as you can (slower charge for deep cycle and faster for starting), keep them fully charged in the off season, handle gently to avoid dropping or banging around, avoid dischaging too deeply, and keep the electrolyte level over the plates at all times to assure long life.

Bob

[Eric Wettschreck]

Like ST said, if a battery can take the pounding I put it through in my truck, it can take the pounding a boat will put it through.

The other guys are spot on as to the dual purpose battery. However, I'll toss this at you just for variety. My boat has 3 deep cycle batteries and one of them is used for the starter. I realize this isn't the best application. But, I had 3 deep cycle batteries that I use for the fish house and camper, so I use them in the boat also, and the deep cycle starts the boat motor just fine. Being the tight wad that I am, I wasn't about to go buy another battery if I didn't really have to.

Just tossin that at you as an option if you have one laying around collecting dust.

[Finns]

Here is probably a simple question---That's what you thought . I'd say go for it!

[PerchJerker]

Its just that I have bad luck with boat batteries! It seems like every year I have to buy a new one.

Do you have a good on-board charger in your boat? An on-board charger will definately extend the life of your batteries, plus keep them in tip-top shape (ie. at maximum capacity). As expensive as batteries are, I think a good on-board charger pays for itself. It will definately pay for itself if you're replacing a battery just about every year.

About your other question, the other guys are right, have your batteries load tested. A tester that shows 100% is just telling you that you're getting 12+ volts out of the battery ..... it doesn't tell you the capacity, ie. will you get 12 volts for several hours, or only for a few minutes???

[Hoffer]

hey guys - EXCELLENT stuff! Bobt I especially liked your explantion.

So, heres the final question. As mentioned I have 3 batteries. I have an on board charge that goes to the bow troller, and the rear accesory battery.

I am going to buy a new one for the rear accessory battery which runs all the stuff like lights, depth finder aerator etc...

I am then going to move the battery that now runs the accessories up to the front bow area and have 2 batteries up there - there is room for 2 - and I figure even if that battery isnt in the greatest condition it would work for a few extra hours at the end of the day if I need to switch over.

So, my question is this:

What kind of battery would you go for in each case? A "dual purpose" was mentioned - would that be good for both the accesssory and starter? or should I go with dual for the accessories and a regular starter for the starting battery?

OR should I go with a regular starter for the starter and a standard deep cycle for the accessory. I guess I am thinking that a new starter battery will be pretty starightforward. i am just wondering what will last the longest for the accessory battery since it is running so many things.

I hope this is a decent post for others to learn from - I feel like its some simple basic stuff - but I bet some other guys have some similar questions...

Thanks again!

[PerchJerker]

If you are buying a battery for trolling motors or for accessories I would go with a deep cycle battery. I would only go with a marine starting or dual purpose battery if it was connected to my engine.

[Hoffer]

Thanks Perchjerker! Thats is what i will do.

I just wish I had the bucks for one of those "optima" type batteries for the accessories - I have been eyeing them - but just cant pull the trigger for that. I could buy 2 "regular" batteries for less than 1 of those - but I know in the long run - I would probably ciome out ahead with the nicer optima battery - as it would probably last longer.

[PerchJerker]

I use regular deep cycle batteries, not Optimas. I haven't run into any problems with not having enough battery power, although it certainly is a possibility if you're running lights, multiple graphs and gps, radio or cd player, vhf radio, pumps, etc. I have all my batteries tied to an on-board charger and make sure I plug it in as soon as I get to the dock or the garage. And I run my accessories off my starting battery so my motor's alternator puts a charge to it, and if I'm worried about it I display the voltage on my locator screens.

If anyone's looking for on-board chargers you can see them here at Pro Fishing Supply On-Board Chargers

[Hoffer]

The guy that had the boat before me - just hooked up the on board charge to the troller and to the accessory battery. i wonder if my locator would show me the voltage? is that common on locators? its a nice one - it has the gps etc...and I just havent played around with it much...I will try to see if ti shows the voltage later today.

Last, I do have a gauge on the dash that shows the voltage for the starter battery. yesterday, i think it showed around 10 when I turned the key...is that kind of low?? what should it read - if I have a full charge??

[PerchJerker]

Fully charged should be around 13 volts.