See full version: Using a Deep Cycle Battery For Starting – What You Must Know
There is a lot of confusion among boat owners about deep cycle batteries and how they work. One question involves the use of different batteries. People want to know if they really need a cranking or a starting battery or if they could just be using their deep cycle battery when starting up their boat motor.
The plates inside of a deep cycle battery has fewer and thicker plates so that the battery is able to easily provide that consistent power. Deep cycle batteries are designed to be drained and recharged many times repeatedly where as that is not the case with a cranking battery.
You should not attempt to use a deep cycle battery for starting your boat, even if it seems like it may be possible.
The best chargers generally tend to be the ones that have three stages; and these chargers also tend to have a lot of safety features equipped including keeping you safe until a battery is properly connected. [links]
If you are discussing a battery’s “cycle”, you are referring to one complete discharge and recharge, known as a cycle. more
However, if you do that you are probably just paying more in the long run and there is a better option for you anyway if you are trying to find one battery for both functions.
The deep cycle battery on your boat is designed to be used after the boat has already started up. Once your boat is running, it is similar to your car in the sense that it doesn’t need huge bursts of energy. What your boat does need is continuous and reliable power from its battery source.
How much a battery has been discharged is often measured in depth of discharge. Basically, this means that if a battery has 50% capacity remaining, the other 50% would be known as its depth of discharge. more
Windsun Energy is an alternate energy source company. Not that they don't know what batteries are all about, but you should also check info from the various battery manufacturers. Most will say sure you can use a deep cycle for starting purposes -- "But". And then there is the whole issue of construction and terminology as pointed out in the quote from the Hull Truth form at the end of this post. Again, I'm not trying to persuade anyone not to use a deep cycle for starting purposes. I do want to make sure that people understand what the consequences are. Here are some quotes:
Re: Is a deep cycle battery ok for starting? here
Interstate Batteries: "However, a marine/RV deep cycle battery typically will not offer the total number of starts youll get from a starting battery."
Here is the first line of Skidoo's post: "Is there any reason I would not want to use a deep cycle battery for starting?" Looks to me like he wants to use it for starting. Therefore your answer to him is misleading. I agree that if you want to carry only one battery, it can be a battery labeled "marine starting/deep cycle". Not to be confused with a battery that is labeled simply "Marine/RV deep cycle". They are not the same construction. If the WalMart battery is labeled "dual purpose" or "Marine Starting/Deep Cycle" it's ok to use it for starting OR accessory use. If it's a standard "Deep Cycle" it is not a good choice for starting duty on that large an engine. By the way, the Optima battery Ezeke pointed us to is totally different construction than a standard flooded battery which the poster is looking at. Even the Optima comes in two varieties. Why do you suppose that is? [links]
The Optima batteries in the link states in the recommended application notes that these are rated "dual purpose" which is what I've been trying to get across. Not all deep cycle batteries are rated "dual purpose". You can use a case of flashlight batteries for starting purposes as well but it certainly is not recommended! As I said in my first response, people use deep cycle batteries for starting duties and get away with it but that is not the intended application. If a battery is specifically labeled for both duties, even the manufacturer will tell you its a compromise in that it will not be ideal for either purpose. more
Re: Is a deep cycle battery ok for starting?
Let’s dive into some additional details about the batteries on your boat and how to care for them.
While it is technically possible to rig something up, the growth of the marine battery industry means that different chargers are available for different settings. [links]
At a bare minimum, a quality battery charger is going to offer all of these features so that you can get a great charge from onboard your boat. This is an area where you need a reliable product, so it doesn’t make much sense to try and save your budget here. here