Which battery to get?

[jeffrobean]

I have a 1980 Sea Raider Runabout with a 50hp Mercury motor. I do not know anything about batteries except for the conversation that I had with a guy in Autozone. Do I need a deep cycle battery? Will a walmart marine battery work? I have two lights and a bilge pump to power. Is there any difference with a deep cycle battery and a normal marine battery? Do they both have to be charged after every time you use it? Please shed some light for me. Thanks.

 

[Isaacm1986]

Re: Which battery to get?

Do a search on batteries, there is SO MUCH info in these forums on the batteries.

Deep cycle batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates - not sponge.

Marine batteries are usually a "hybrid", and fall between the starting and deep-cycle batteries, In the hybrid, the plates may be composed of Lead sponge, but it is coarser and heavier than that used in starting batteries.

Hope this helps.

 

[Greg Mrozinski]

Re: Which battery to get?

Jeff,

Marine batteries come in three different categories - Marine starting, marine dual purpose (combo starting/deep cycle) and marine deep cycle. Marine starting batteries are very similar to your car battery except made more heavy duty to take the shock and vibration in the marine environment. Starting batteries are designed for short high drain usage like cranking over an engine. Starting batteries are not designed for long term repeated constant use and drain. Deep cycle batteries are the opposite and they are not generally good for short term heavy drain like starting an engine. They are designed though for repeated constant drain and recharging cycles. The dual purpose batteries are just that in they fall in between and can be used for both puposes but they do not last as long as a true deep cycle only battery. The battery should be labled accordingly (i.e. Marine starting/cranking, dual purpose marine, deep cycle marine)

Each if these can also come in three different types of batteries - wet cell (lead acid), AGM (absorbed glass mat) and GEL cell. Basically they all work the same except the lead plates and electrolite are configure differently (lead plates vs. lead sponge vs. gel electrolyte vs. liquid electrolyte/acid) in each type to maximize the properties of specific characteristics.

For your boat I would probably shoot for a dual purpose wet cell battery in a Group 24 or 27 size (check your engine manual for the recommended minimum size; you can always go bigger). They are the most affordable and will allow some flexibility for both starting and then running a stereo or lights when floating.

 

[JoLin]

Re: Which battery to get?

Okay, couple things:

1. If you have one battery on the boat, you want it to be either a marine startng battery, or a hybrid (cross between a starting and a deep cycle battery). Pure deep cycle isn't your best choice.

2, The way your boat is equipped you have very little current draw aside from starting your motor.

3. Your motor's alternator is generally sufficient to keep up the battery.

4. You should mount a voltmeter on the boat and keep an eye on charge. A fully charged lead-acid battery "at rest" puts out 12.6 volts. They all do-it's a function of the chemical reaaction inside the battery, With your alternator running, should be 13.5-14+ volts. If at rest the voltage drops to under 11 volts, start the motor while you still can.

6. If you see that the battery slowly loses charge under normal use, because you're drawing more than the alternator is replacing, you'll put it on a charger. Again, a voltmeter is your friend. That situation would generally point up the need for a second battery.

Hope this helps a little.

(oh, and there's nothing wrong with a Wal-Mart battery)

 

[JoLin]

Re: Which battery to get?

Jeff,

For your boat I would probably shoot for a dual purpose wet cell battery in a Group 24 or 27 size (check your engine manual for the recommended minimum size; you can always go bigger). They are the most affordable and will allow some flexibility for both starting and then running a stereo or lights when floating.

Yup. And everything else Greg said, too.

 

[Yepblaze]

Re: Which battery to get?

The Walmart marine max will be fine.

It will allow good cranking voltage and deep cycle capabilities too