Battery Run Time

We Recommend using “Deep Cycle Batteries” to power your lights. “Car” batteries and “Marine Starting” batteries are not designed to be quickly discharged and recharged on a regular basis. These types of batteries will run down much faster than a Deep Cycle Battery and your light will not burn as bright or as long as it should.

A Simple Formula to find out how long a light will run off of your particular battery is to take the batteries “amp-hour rating” and divide it by the total amps being pulled from the battery per hour.   (Amp Hour Rating of Battery / Total Amps = Total Run Time).  For example, a 30-watt COB draws about 2.5 amps., so a 8 amp hr. battery would run the light for about 3.2 hrs. (8/2.5= 3.2)

Common Full Size Deep Cycle Batteries

Battery TypeAmp Hour RatingVoltage
Group 27100-115 Amp Hours12 Volts
Group 29110-125 Amp Hours12 Volts

Compact Deep Cycle Batteries

For those of you who need a smaller battery that will fit in a back pack, the compact batteries listed below will provide good light for a limited amount of time.  Most compact batteries such as the 8-amp hour rechargeable battery from Cabela’s shown below, come with ‘Spade Clip” connections.  We offer our FlounderPro 2000 with with either “Battery Clips” or “Spade Clips”, so be sure and order the correct set of connections that will fit the battery you are using.

To find out how long a light will run on any given battery you take the Amp Hour rating of the battery and divide it by the amp draw of the light. For example, a 30-watt COB draws about 2.5 amps., so a 8 amp hr. battery would run the light for about 3.2 hrs. (8/2.5= 3.2)


Cabelas 8 amp hour battery

Starting Batteries vs Deep Cycle Batteries

Both “Starting” batteries and most “Deep Cycle” batteries are lead-acid batteries that use exactly the same chemistry for their operation. The difference is in the way that the batteries optimize their design:

A “Starting Battery” is designed to provide a large amount of current for a short period of time.

This surge of current is needed to turn the engine over during starting. Once the engine starts, the alternator provides all the power that the car needs, so a starting battery may go through its entire life without ever being drained of more than 20 percent of its total capacity. Used in this way, a starting battery can last a number of years. To achieve a large amount of current, a starting battery uses thin plates to increase its surface area.

A “Deep Cycle Battery” is designed to provide a steady amount of current over a long period of time.

A Deep Cycle Battery can provide a surge when needed, but nothing like the surge a car battery can. A deep cycle battery is designed to be deeply discharged over and over again (this is something that would ruin a car battery quickly). To accomplish this a deep cycle battery uses thicker plates.

A Starting Battery typically has two ratings: CCA (Cold Cranking Amps) – The number of amps that the battery can produce at 32 degrees F (0 degrees C) for 30 seconds.

RC (Reserve Capacity) – The number of minutes that the battery can deliver 25 amps while keeping its voltage above 10.5 volts.

Typically, a Deep Cycle Battery will have two or three times the RC of a Starting Battery, but it will deliver one-half or three-quarters the CCAs. In addition a deep cycle battery can withstand several hundred total discharge/recharge cycles, while a Starting battery is not designed to be totally discharged before recharging.

The bottom line is… Use Marine “Deep Cycle Batteries” for your lights and trolling motor, and a “Marine Starting battery” for starting your boat.

Notice: For best performance a Group 27, 115 amp hr. Deep Cycle battery or better is recommended. While these lights are extremely bright, they require sufficient amperage to operate at maximum brightness. If you are using a generator or have an AC outlet on your dock, you can power your lights with a AC to DC converter.

Always use a converter that puts out more amperage than you need. The more amperage…the brighter the light will be!

Linking your batteries – Parallel vs Series

Be sure you connect your batteries correctly! 

Battery Wiring



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