Marine Battery Information

CCA Cold Cranking Amps

Cold Cranking Amps is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating is the number of amps a new, fully charged battery can deliver at 0° Fahrenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery. The higher the CCA rating, the greater the starting power of the battery.

MCA or CA rates

This is a rating used to describe the discharge load in amperes which a new, fully charged battery at 32 degrees F (0C), can continuously deliver for 30 seconds and maintain a terminal voltage equal or greater than 1.2 volts per cell. It is sometimes referred to as Marine Cranking Amps or Cranking Amps.

RC Reserve Capacity

Reserve Capacity, (RC) This rating is the number of minutes a battery at 80 degrees F can be discharged at 25 amps and maintain a voltage of 10.5 volts for a 12 volt battery. Think of this as how many gallons does my gas tank hold. When you connect batteries in a parallel circuit you can add the CCA ratings together to obtain the total CCA, for instance two,155 CCA batteries connected in parallel would give you 310 CCA total. It would still be 12 volts available. If you connect the same batteries in series you would have 155 CCA at 24 volts. What needs to be considered is that 24 volts will require one half the amps to deliver the same thrust as 12 volts. That is the logic as to why I use a three battery 36 volt system. My cranking battery is my third battery. When the big motor is running that battery is being replenished. My current draw is one third less than a 24 volt system. Even on the delta it is very rare that I will pull the dedicated trolling batteries to less than fifty percent and because the cranking battery is being replenished it will always be much less. Some anglers do not feel comfortable with this setup so they will run a four battery system. The only time I have ever had trouble with this system is when I neglected the batteries and let them get low on water. One mere reason to run Optima’s, you do not need to add water.


Remove the batteries surface charge.
Electrical charges on the surface of the battery positive plates cause a falsely high voltmeter reading. Removal of this so-called surface charge is required on batteries that have been charged by an alternator or a battery charger within 48 hours. Batteries that have not been run or charged on a charger within 48 hours will not have significant surface charge.

To remove the surface charge, you'll need to slightly discharge the batteries. This can be done by using a carbon pile load tester to load each battery to one quarter of its cold cranking amps rating for 15 seconds. Fifteen seconds is long enough to dissipate the surface charge from the plates. The surface charge can be removed by simply turning on the vehicles lights, bilge pumps, or trolling motor- without starting the engine - for five minutes per battery. Then let them stabilize for a few minutes for best results.

State of Charge

You will need a accurate digital voltmeter to test the state of charge. A good digital voltmeter will be function of a quality battery tester. An analog voltmeter or gauge will not get the job done.

The state-of-charge of sealed batteries cannot be determined by looking at the specific gravity of the electrolyte, since the batteries are, well, sealed! State of charge can be determined by measuring the voltage; this is most accurate when the battery has been removed from a load for at least 6 hours, preferably 24 hours. Otherwise voltage values can fluctuate based on whether the battery is being charged or discharged. Here is a chart showing different levels of charge for flooded lead-acid and sealed batteries – open circuit voltage.

Comparison of Battery State-of-Chart to Open Circuit Voltage for 12-Volt Batteries

To test the battery health you will have to have good battery tester such as the Solar BA-5 or BA-7. These testers will tell you the overall health of your batteries, a voltmeter only tells you the state of charge it will not tell you anything about the condition of the batteries. They can also test the alternator and starter circuits. These testers are not all that expensive and are available at any Napa Auto Parts store. Every bass fisherman should own one.

OPTIMA Blue Top Charging Information

The following charging methods are recommended to insure a long battery life - always use a voltage-regulated charger, with voltage limits set as described below.

Blue Top Type: 34M_This battery is designed for engine starting applications. They are NOT recommended or warranted for use in deep cycle applications.

Recommended charging information:

. 13.3 to 15.0 volts, no amperage limit.

Battery Charger:
. 13.8 to 15.0 volts, 10 amps maximum, 6-12 hours approximate.

Rapid Recharge:
. Maximum voltage 15.6 volts (regulated), no current limit as long as battery temperature remains below 125°F (51.7°C). Charge until current drops below 1 amp.

Float Charge:
. 13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).

_All limits must be strictly adhered to.
Blue Top Type: D34M / D31M/ D27M_These batteries are dual purpose. They are designed for engine starting and deep cycling applications and for use in boats with large accessory loads.

Recommended charging information:
. 13.65 to 15.0 volts, no amperage limit.

Battery Charger:
. 13.8 to 15.0 volts, 10 amps maximum, 6-12 hours approximate.

Cyclic Applications:
. 14.7 volts, no current limit as long as battery temperature remains below 125°F (51.7°C). When current falls below 1 amp, finish with 2 amp constant current for 1 hour for D34M and 3 amp constant current for 1 hour for D31M.

Rapid Recharge:
. Maximum voltage 15.6 volts (regulated), no current limit as long as battery temperature remains below 125°F (51.7°C). Charge until current drops below 1 amp.

Float Charge:
. 13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).
All limits must be strictly adhered to.

If you have completely discharged Optima batteries you will need to temporarily jump it to a charged battery in order to initiate the charging process. Many Optima’s are returned as defective because this procedure was not followed. __

Safety Information:
. Always turn off battery charger before disconnecting.
. Always wear safety glasses when working with batteries.
. Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gasses to escape, resulting in premature failure. These gasses are flammable! You cannot replace water in sealed batteries that have been overcharged. Any battery that becomes very hot or makes a hissing sound while recharging should have the charger turned off immediately. DO NOT DISCONECT due to risk of spark causing explosion.
. Failure to fully charge a battery can result in poor performance and a reduction in capacity.

Battery Maintenance is an important issue. The battery should be cleaned using a baking soda and water solution; a couple of table spoons to a pint of water. Do not get any of this solution into the battery cells, it will neutralize the electrolyte. Cable connections need to be cleaned and tightened as battery problems are often caused by dirty and loose connections. A serviceable battery needs to have the fluid level checked. Use should only mineral free water, Distilled is best as all impurities have been removed, and there is nothing left that could contaminate your cells. Don't overfill battery cells especially in warmer weather because the natural fluid expansion in hot weather can push excess electrolytes from the battery. To prevent corrosion of cables on top post batteries use a small bead of silicon sealer at the base of the post and place a felt battery washer over it. Coat the washer with high temperature grease or petroleum jelly (Vaseline), then place cable on the post and tighten. Coat the exposed cable end with the grease. Most folks don't know that just the gases from the battery condensing on metal parts cause most corrosion.

Battery Chargers
Do no buy cheap chargers
Buy automatic chargers that have a quick charge mode
More importantly make sure that they have a 10 amp max automatic charge mode

That they have a battery maintainer mode that will drop 1 amp or less Make sure that they are selectable for your battery type Gel Cell. AGM etc.

What This All Means To Me as a avid Bass Fisherman and Automotive Technician.

After over forty years of experience dealing with starting and charging systems from lawn mowers to caterpillars I have definitely formed some opinions of what works and what does not. Unlike some I am totally convinced that a boats cranking battery must be a deep cycle such as the Napa deep cycles or dual purpose such as the Optima Blue tops. Most boaters are running various accessories of the cranking battery such as live well pumps, bilge pumps and various electronics without the motor running thus they are cycling the state of charge of the battery. CRANKING BATTERIES ARE NOT DESIGNED FOR THIS! It will shorten their life and reduce battery performance quickly. My number one concern is getting the maximum reserve capacity that I can fit into the space available. The cold cranking amps will be more than ample for any thing I need in a bass boat. By using maximum reserve I will not normally cycle the batteries as low, which in turn will provide for a longer lasting battery that will provide a much higher CCA as it ages, I used to be concerned about the lower reserve in Optima batteries in comparison to flooded lead/acid I realized two things. One being that you can get as many as three times as many charge cycles with Optima’s. Two being that after batteries have aged for a year or two that the, Optima will now have the greater reserve, which means better battery performance for me. I am currently running, three Optima D31M. Setup for 24/36, My cranking motor battery is my final battery for my 36 volt system, by using 36 volts the amperage required is quite low for normal trolling motor operation. When running the big motor thru out the day it keeps that battery replenished well.

I do not understand why the manufactures are recommending such extremely high cca for the newer motors, they actually require less than 200 amps to crank them under the worst conditions. A 1000 cca battery will reliably start a duramax diesel! I think they must be trying to use more battery power to cover up design inadequacies. I have seen these motors operate for long periods of time with 600 cca batteries with no problems of any kind; therefore I must believe that those recommendations’ are to cover up design problems and or operator abuse.

First if they require this much battery. Cables used with these motors should be at least a 2 gauge, 0 would be even better.

Second any high current loads must be moved to another battery source,

Three, they must be hooked up to the correct charger as soon as possible after use and verified that they are brought back up to 100% charge.

Fourth I firmly believe that the cranking battery should be as large a deep cycle or dual purpose such as the optima d31. The reason being almost all boaters have various electrical accessories operating with the engine off. After a partial discharge the deep cycles will provide more usable cca, especially when the batteries start approaching two years old. Also they will recover faster after a partial draw down when running the big motor. Please do not get me wrong on this subject, as that commercial goes You can't get enough good stuff. I personally use the largest group size Blue top Optima’s that I can fit into the space available. My number one consideration with marine batteries is maximum reserve capacity, Cold Cranking amps second.

Please keep in mind the alternator on your boat motor or tow vehicle is NOT A BATTEY CHARGER, it is a battery maintainer. It is very hard on alternators to use them to recharge batteries and it will take hours for the alternator to bring depleted batteries to a full charge.

If you have any questions regarding electrical systems or for that matter any Automotive related questions you can contact me at the sources listed below.

Leon Pugh

Home Ph 916 333 4105
Cell Ph 916 813 0321

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