Deep cycle?

[Destroyer]

Originally Posted by THEFERMANATOR

Just because you can, does not meen you SHOULD. Deep cycles can give high amperage loads when needed for starting, but any good deep cycle battery is designed to put out low to moderate amperage amounts for longer periods of time. Using true deep cycle batteries for cranking WILL shorten the batteries life, that's an undisputable fact. The thing is there is very few TRUE deep cycle batteries in the group 24/27 range because they know people are going to abuse them as starting batteries. True deep cycle batteries will not have a cranking amp rating, only amp/hour ratings which is what is important to a deep cycle battery.

X2. A regular car battery, either traditional lead/acid or AGM (Absorbed Glass Matt) is more than sufficient for most boats. If you're running an electric trolling motor from a small skiff or rowboat then a deep cycle battery comes into play. But for regular day to day usage just a straight car battery is fine (And usually costs less) By way of further explanation, allow me to copy/paste a quick article about the types of batteries. (Keep in mind this does not include Lithium-Ion batteries which are very expensive and not really practical for boat use unless you have an electric powered car or boat)

Types of batteries:
1) Wet/Flooded Battery: The wet/flooded battery is one of the most popular types of batteries. It is so popular because the battery price is very low. The battery design uses plates that are freely suspended. These plates are insulated from each other as the negative plate is completely sealed in a separator bag. These are maintenance free and sealed so no gases are replaced. The fluid in the battery will last until the battery dies and you do not have to keep topping it off. These batteries can range from $50 to several hundreds of dollars depending on the brand.
2) Calcium-Calcium Battery: This battery has a calcium alloy that is on the different charged plates. This calcium reduces the amount of fluid loss and the rate of self discharge is much slower. The main disadvantage is that you can seriously damage the battery if you overcharge it. The bubbles that move through the fluid are important, as they are responsible for mixing the different acid densities. You can find a calcium-calcium battery for under $100.
3) VRLA: The VRLA stands for a valve regulated lead acid battery. This name really describes the safety valves that are on the battery box. The safety valves are all pressurized. By containing the gas in the battery it will mix and form water so you stop any fluid loss. There are two main designs of this VRLA battery: AGM or GEL. A GEL battery uses silicon to make the acid more solid and like a gel. This type of battery is very good but is not the best for a starter battery. This type of battery costs between $100 to $250.The AGM battery uses absorbed glass matt. The matts are very thin, which keeps internal resistance very low. This makes it a perfect battery for starting a car, as you can get a lot of power out of very small volume. AGM batteries price range anywhere from $50 to $300 depending on the brand.
4) Deep Cycle: A deep cycle battery will provide power for a very long time. These are typically used on small boats, golf carts, or electric vehicles. You will also find these used to collect and store solar and wind power. These batteries have thicker plates inside the battery as this increases the capacity charge. They are typically not used for cars or boats because they have a high discharge rate, so the battery will run down very quickly. If you do not drive your vehicle for a long time, then you will not sufficiently recharge the battery. Deep cycle batteries are expensive and starting prices are about $200.

Hope this helps clear up what kinds and how these batteries work.

[bradford]

Direct injected 2 stroke power with 2 1000 MCA Interstates on an Awl gripped hull riding on an aluminum I beam bunk trailer without any brakes pulled by at least a Chevy or gmc if not a Toyota.

Tell Charlie to get the white one with the tailgate, MJ to hard wire the float switch to the battery, and Stinky Hooker to put some pants on.

[Genie Aye]

Sorry, I still disagree with you, I sold Deka(east Penn manufacturing) batteries for years and had factory training. Some manufacturers, maybe, not all batteries are the same despite their purpose. I will leave it there.

[SkunkBoat]

I guess we all got to the bottom of this topic....

[spareparts]

Every engine manufacture states in their installation guide specifically to NOT use deep cycle batteries as a starting battery. Deep cycle batteries are for trolling motors and battery banks. A starting battery will run all your electronics and them some. Using a deep cycle battery for electronics comes from the car stereo guys(oddly enough, they will do better with a starting than DC) and has no merit. I sell quite a few batteries each year and can tell you, all batteries are not the same. The Deka 24M7 is probably the best battery out there right now. You can use a deep cycle battery to start an engine, buts its not the best battery to use. Use of an incorrect battery can effect your engines warranty as well. Mercury has gotten very specific about it with their outboards

[SkunkBoat]

Mercury has to blame it on something....
**************************************

I think the key to this argument is the application of the battery.
I think most V20s are run during daylight and have minimal draw on the battery for short periods before running and thus recharging.In this application, a starting battery will be fine.

I used to drift or anchor for hours, often at night. I used to turn on my floods and underwater light at the dock and fish for stripers under the dock. It wouldn't get charged until the next time I ran it. I used a single 27DP for 18 years and it worked great.

As for a DC, they are for House batteries on large boats with multiple banks or for electric trolling motors.


Here is West Marine's take on battery selection.

Starting batteries

Starting batteries, which crank the starter of your boat's engine, are the sprinters of your electrical system. They deliver between 75 and 400 amperes for 5-15 seconds, and then are recharged in short order by your engine's alternator. Like all lead-acid batteries, they are constructed with alternating layers of negative and positive plates with insulation between them.

Starting batteries have thinner and more numerous plates, providing extra surface area to generate high amperage bursts of current. The two drawbacks of this construction are that the plates are relatively fragile in high-impact environments, and that starting batteries do not tolerate deep discharges, which reduce their operating lifespan.

Deep cycle batteries

Your boat's house battery bank uses deep cycle batteries, the marathon runners of the storage system. They power the electrical loads on your boat when no charge source (shore power charger, engine alternator, wind generator or solar panel) is available. Consider them a kind of savings account into which energy is deposited or withdrawn.

Compared to starting batteries, which deliver high bursts of energy for short periods, deep cycle batteries recover fully after being heavily discharged over longer periods because their design features thicker plates with a high content of antimony. Overnight, their use might deplete 50-70 percent of the battery capacity, depending on the house loads of the boat. When the batteries are recharged, energy is re-deposited into the bank, and the process, or cycle, starts over. Generally, deep cycle batteries should be sized to store three to four times the expected amount of energy to be used between recharge cycles.


Dual-purpose batteries

We generally advise that you choose either a deep cycle or starting battery for best performance and battery life, but dual-purpose batteries work well in some applications. With large, thick plates containing more antimony than starting batteries and an active lead paste chemistry, dual-purpose batteries are a good compromise, tolerating deep discharges that would ruin a typical starting battery. Since they have lower storage capacity than comparably-sized deep cycles, we recommend them for the following applications:

Runabouts or other small powerboats using a single battery for both starting and running loads with the engine turned off.
Sailboats with two identical batteries used interchangeably for starting and house electrical loads.
Boats with one battery bank that does double-duty for house applications and engine starting. Dual-purpose batteries will last longer and give more reliable service than a starting battery, for about $20 more per battery.

[Genie Aye]

It would to be great to have a Agm starting battery and 2 DC house batteries, but where to put them?
I use 2 group 27dc delays, I power alot of equipment, more than alot of bigger boats.
I would not be suprised to see merc require a Agm for starting, alot of cars do.

I was just stating that a DC battery will work fine for starting 90% of the outboards out there. Most do not require over 450amps to start, even a centennial battery might do that...maybe.

[Destroyer]

Originally Posted by Genie Aye

Sorry, I still disagree with you, I sold Deka(east Penn manufacturing) batteries for years and had factory training. Some manufacturers, maybe, not all batteries are the same despite their purpose. I will leave it there.

No one is saying that your batteries won't work. We're simply saying that it's really not necessary to go with batteries that are that expensive. It's a fact that deep cycle batteries cost more than regular lead/acid and really don't deliver any added value for normal usage.