How to keep batteries properly charged

We’ve all been there. You know, you walk out to the boat the morning of the trip you’ve been planning for a week and the batteries aren’t charged.

No power. Nada. Zip.

Then it’s off to blow your budget on a new set of batteries.

But Front to Back Boat Service’s Ken Sherman offered some thoughts on maintaining the components that start the outboard and run all the electronics we count on.

His first piece of advice is to stop leaving the trickle charger on 24/7. This flies in the face of some other experts’ advice, but Sherman said there’s a simple reason.

“In reality, in South Louisiana, you see these vicious storms we have come through here with all the lightning,” he explained. “Well, what happens is: You leave (the charger) plugged into 110 (volts), lightning strikes down the road, hits the power line, surges — bam, burns the charger.

“Next thing you know we’ve got round batteries, and the batteries are not in good shape.”

He said trickle chargers have a component called a fet that regulates the charging amps being sent to the battery. When a battery fully charges, the fet kicks in to reduce the amps to a trickle — thus the name “trickle charger.”

If a surge hits the charger and burns out that regulator, the charger sends a full charge to the batteries — even when full charge is reached. The result can be an overcharged battery.

There’s an easy test to ensure you don’t have an overcharged flooded-cell battery that could leave you dead in the water.

“If you push the ends of a flooded-cell battery, it should be soft,” Sherman said. “If (your batteries are) hard, you just as soon look at getting some new ones.”

To guard against overcharging, Sherman simply plugs in his charger after a trip until all the lights turn green, and then he unplugs the charger until he’s ready to go out again.

“Just before you leave, plug it in, let it go through a cycle,” he said. “The good thing about it is that if you did have something happen to a charging system with lightning striking it and you didn’t catch it, you’re not going to burn a battery up by leaving it on all the time.

“So if you charge it when you get in (from a trip), get up the next morning (and see) all green lights — unplug it. You know you’re leaving on Saturday morning: Friday you get in from work, plug it in. You may plug it in and within 10 to 15 minutes, it’s all green, you can unplug it.”

He said doing this will prolong the life of your batteries.

But just how long should a battery last? That depends on the type of battery you use.

It’s a safe bet most anglers still use flooded-cell batteries because they are widely available and are generally the least-expensive option.

Sherman said maintaining the proper water level is important in getting the most out of these batteries.

If you find a battery isn’t lasting all day, you can use a conventional charger to force a full charge.

“Get a good punch on it, get it warmed up, get it to pull up to temperature, and you may be able to save it,” Sherman said. “But you’re probably going to find your day usage may not be as long if you’re working on a saved (flooded-cell) battery.”

The simple fact is flooded-cells just don’t last as long as the more-expensive AGM batteries.

“If you’ve got two years on a flooded-cell battery and you’re a hard-core fisherman, pull them out and put new ones in,” Sherman said. “That’s the best move you can make on flooded-cell batteries.”

AGM batteries that are properly maintained, on the other hand, can last for years. That balances out the initial cost factor.

“The new AGM batteries are really getting the prices down where they are very affordable,” Sherman said. “These batteries are lasting six, seven, eight years.”

And, even better, AGM models aren’t as susceptible to cold weather.