Deep cycle vs regular battery

[Air Traffic]

I have a 27ft cruiser with twin 4.3 I/O's. It has dual batteries with a switch for each engine, it appears my number 1 battery is going bad ( 4 years old). I will put a load tester on it to make sure. It will run the blower or radio but jusy clicks when you try to start either engine. Now the question. Currently both batteries are deep cycle but since I don't run any electric trolling motors or such and if I want to run the radio off a battery I can always select the deep cycle, do I need another deep cycle or wpuld a regular automotive battery wlrk as well?

 

[bonz_d]

Re: Deep cycle vs regular battery

Replace with a starting battery.

The two types of batteries are completely different. A regular starting battery is designed to crank engines were there is a huge short amperage draw and then to be recharged. Short cycled.
A deep cycle battery is designed to be charged then drawn all the way down before it is recharged. Short cycling these batteries actually shortens their useful life.

 

[H20Rat]

Re: Deep cycle vs regular battery

A deep cycle battery is designed to be charged then drawn all the way down before it is recharged. Short cycling these batteries actually shortens their useful life.

No, on many levels. I'm guessing you are confusing lead acid deep cycles with NiCad or NiMH cell batteries. (those guys need a deep discharge every so often)

Anyway, 1) Deep cycles will work as starting batteries, they just provide lower CCA's than a regular battery. They are not harmed in any way though by doing that. 2) Actually doing a deep cycle (below 20%) on a deep cycle battery is BAD. They can withstand it better than a regular battery, but the absolute last thing you want to do is completely discharge a deep cycle before charging. A battery cycled to 50% will last 5x longer than one cycled to 10%.

Here is a handy chart of the # of cycles vs the discharge amount... (keep in mind its logarithmic) (stolen from deep cycle - cycles vs life

 

[lakegeorge]

Re: Deep cycle vs regular battery

Go with a more powerful battery, the cost difference is minimal.

 

[Texasmark]

Re: Deep cycle vs regular battery

Popular use of deep cycle batteries came about (opinion) when trolling motors became popular. Usage of the batteries available at the time indicated that a regular starting battery used in multiple deep draw down operations, aka trolling motor usage, caused problem with the multiple thin plates that are required to get enough surface area for high current blasts like starting your engine, and premature failures were common.

The deep cycle was born and since the problem was thin plates, the plates were thickened. With a battery case as a limiting factor there was not room for as many plates so they were reduced in number. Each plate of either battery has two sides in contact with the electrolyte. The current that is emitted by the battery is an interaction of the electrolyte and the surface of the plates. Deep cycles, with fewer plates, were not intended for high currents were not expected and thus were of no concern.

In today's market some batteries are advertised as dual purpose. I have no idea as to the mechanics of their design.

Years ago I bought a 300 cubic inch John Deere diesel tractor. I live in Texas and winters seldom get below 10F. The battery in the tractor, single battery, was an old Exide size 27 deep cycle and had obviously been in there for many years. I continued to use it for several years and it did a good job of starting my diesel in the winter even though it was not designed for the job and was an old battery. Starting a diesel engine in the winter is enough of a problem getting the compressed air hot enough to explode a diesel mist. The crankcase oil is thick adding to the problem. The battery capacity is reduced in cold weather. The battery was not designed as a starting battery. All negative factors, but the battery did the job. Must have been an exception.

Why not buy a combination deep cycle/run and you won't have to worry about it. I know Wally World carries them as I have bought them. Otherwise if you plan to run your boom boom box or some other deep cycling mechanism then I'd go with the deep cycle.

My 2c,
Mark

 

[etracer68]

Re: Deep cycle vs regular battery

I have used heavy duty auto type batterys for starting batterys only, and didnt have any issues. And in my opinon, you should have an "house battery" also. This (house battery) should be an deep cycle, large size, and cap. The house battery should then be used when not running, to run the radio, and other things. You will have to find out how to set it up, so it will charge up when running though. My opinon, and I never use a starting battery to run other things.

 

[bonz_d]

Re: Deep cycle vs regular battery

No, on many levels. I'm guessing you are confusing lead acid deep cycles with NiCad or NiMH cell batteries. (those guys need a deep discharge every so often)

No. I am actually going by what I've learned over the past 30+ years of dealing and working with electric fork lift batteries and the many discussions I've have with battery distrubutors and manufacturers along with the companies that make and service the chargers for them. Such as a 48 volt 1200 amp battey that weighs almost 800lbs and uses welding size cables on the terminals.

 

[UncleWillie]

Re: Deep cycle vs regular battery

it appears my number 1 battery is going bad ( 4 years old). I will put a load tester on it to make sure. It will run the blower or radio but just clicks when you try to start either engine...

Be sure the battery is actually Bad before you replace it.
Charge up the battery.
Place a volt meter on the actual Battery posts. NOT the Clamps or the cables.
Attempt to crank the engine. If over 11v volts, Bad connection somewhere. If under 10v, Bad Battery.