The Best Marine Battery Starts with the Battery Plates
To Get the Best Marine Battery installation on your Yacht, you have to know what you want to buy before you can research which one you want. The first thing to know about marine batteries is the difference between Deep Cycle Marine Batteries, and Starting Marine Batteries.
Starting Batteries have skinny lead plates, creating lots of surface area for a very fast chemical interaction between the acid and the lead. This interaction creates enough power in flooded designs to manufacture the power required to turn over a starter motor. As battery designs have evolved from the original flooded lead acid battery, through Gel designs, and now to Advanced AGM Marine batteries, the difference between the power of starting batteries has been reduced. Now a days, you can use deep cycle batteries in place of starting batteries, as long as you pay attention to the cranking amps for your motors. We recommend adding a second battery to alleviate getting stranded while you fish with the radio on, but that is another story for another page.
Starting batteries are measured in cranking amps. The cranking amps measurement is taken by measuring the maximum amperage output from a fully charged marine battery for 15 seconds. When starting a diesel motor for example, at least 800 cranking amps is recommended. A Honda PWC starts on less than 300 cranking amps, but still requires hundreds of amps to push the starter over.
When your boat has several motors, big diesels, or other "hard to start" equipment, pay special attention, and consider separating the circuits into starting batteries, and house batteries. When you are going distances, consider installing redundant system. You can't be caught on the water without the ability to start the motors or it gets expensive quickly. When choosing starting batteries, this MUST be your ONLY concern.
Generally there is no rule, we have developed these guidelines for personal use, and wish to share them:
Engines under 800 horsepower: 1 starting battery or 2 deep cycle batteries (fishing boats, ski boats, etc.).
Engines under 800 HP with Cabins: 2 starting batteries and separate house batteries to taste (yachts, pontoons, sailboats, etc.).
Engines over 800 HP: Mandatory 2 starting batteries, test for four.
Next step in the best marine battery setup, deep cycle batteries.
Deep Cycle Marine Batteries are designed with thick lead plates, that can withstand the reaction in the acid electrolyte bath for a sustained period of time. The resulting stability allows a deep cycle battery to discharge power over the course of hours, minutes, or even days. Deep cycle batteries are what you should use to power stereos, televisions, refrigerators, and other necessary equipment on your boat, as opposed to starting batteries, because they can take it.
The lesson for the best marine battery installation; put the right type of marine battery in the right place, and buy enough of them.
Typically we have seen users who tried to use a starting battery in lieu of a deep cycle battery come back in 30-90 days, complaining about their decisions. Users who purchased too small a deep cycle bank, haven't the cranking amps to start the motors. Users who purchased too little a house bank, were back in 60 days as well.