Hard Life of a Battery

By Steve Thompson, Contributing Editor

When you turn the key to "start" on your tractor, riding mower, utility vehicle or pickup, you expect the engine to roar to life. If the battery is low or "dead" and the engine won't start, that "oh no" feeling takes over, followed by several seconds of "what do I do now?"

You've just experienced "dead battery syndrome."

The battery is a hard worker. While storing chemical energy for the complete electrical system, it must be ready to supply immediate current for starting the engine. That is a battery's most demanding job. Bringing an idle engine to life requires the battery to generate enough amps to spin the starter to turn over the engine.

But the battery has two other important roles. First, the battery supplies current when the demand of the vehicle exceeds the output of the charging system. Since current demands are constantly changing due to lights, air conditioning, fans and other accessories, the battery is always there in a "standby" role. Second, the battery stabilizes the voltage in the system during operation.

How a battery charges and discharges is unique. A battery produces current by a chemical reaction, and this chemical reaction discharges the battery. Therefore, the battery must be charged either by the alternator or generator on the unit it powers, or by a battery charger.

CHEMISTRY OF POWER

Charging a battery simply reverses the chemical action of the battery. Battery charging is usually as simple as hooking the red lead from the charger to the positive post and the black lead to the negative post.

But wait -- it's not always that simple.

Equipment on the farm may have multiple batteries, and they can be connected in either series (like a late-model JD 4020, where two 6-volt batteries make 12 volts) or parallel, where two 12-volt batteries still make 12 volts -- such as your diesel pickup or larger tractor.

Because of the use of different circuits, proper and safe battery charging can get a little tricky.

BATTERIES IN A SERIES

If your system is a 12-volt negative ground with two 6-volt batteries, your batteries are in series, and you can easily charge both batteries at the same time by placing the red charger cable on the starter solenoid where the positive cable goes.

Many manufacturers use a big nut to secure the cable for charging and jump-start ease.

However, you can successfully charge (with the charger set on 12 volts) both batteries in series at the same time only if both 6-volt battery voltages are within 0.1 volts of each other. Otherwise, the batteries must be charged individually.

Batteries connected in parallel (meaning that the voltage of the batteries together still produce the same voltage as each battery individually, as is the case in many diesel pickups and late-model larger tractors) can be charged together without disconnecting them only when each batteries voltage is above 12 volts.

SAFE CHARGING

Be careful charging batteries. Make sure you know the polarity of the system and the voltage of the system. Many older tractors came from the factory as positive ground systems. But it was thought that this polarity caused more frame rust, so manufacturers changed to negative ground.

Many older systems that were originally positive ground systems (6- and 12-volt) have been changed to negative ground systems when the tractor was converted from a generator to an alternator. An alternator, unlike a generator, will charge no matter which way it is turning, but it doesn't like to charge unless the system is a negative ground.

When you install a new battery and the alternator won't charge, always check to make sure you installed the battery as negative ground.

Play it safe around batteries. Always wear safety goggles and rubber gloves when charging a battery. Keep sparks and flames away from the battery as the battery generates harmful fumes, and explosive gas can blow up.

Weak batteries hold a hidden risk all their own. If a battery drops below a 40% charge, it can freeze when the temperature reaches -16 degrees Fahrenheit. Never try to charge a frozen battery. It can explode.

Which cable first? Disconnect the ground cable first when removing the battery to avoid sparks. When installing the battery, connect the ground cable last to help avoid sparks. Remember, it's possible in old tractors for the cable leading from the positive post to be the ground cable.

If you have ever seen a battery blow up, you'll never forget it -- and you may never see it again if the acid gets in your eyes.

Replacing a worn-out battery with the recommended battery for your unit, combined with proper battery maintenance, will extend battery life.

Keeping the battery filled to its recommended level is important. Fill with distilled water or clean, soft water. Overcharging and undercharging are enemies of battery life, and repeated cycling (discharging and charging) will shorten battery life.

Although the battery is one of your hardest working friends on the farm or ranch, it has many enemies, including dirt, heat and vibration, all of which hang around farm equipment.

For peak performance and long battery life, remember the following:

-- Shield the battery from engine heat, if possible.

-- Secure the battery to keep shaking and vibration to a minimum.

-- Keep the battery topped off with distilled or soft water.

-- Keep the battery clean and charged -- battery cable cleaner is available at the auto store.

An enemy of battery life, more than any other, is a loose battery that bounces around when the equipment is running. Vibration and bouncing can cause external and internal damage to the battery.

Seasonal equipment, such as a combine and self-propelled hay swather, are not usually run enough in the off-season to keep the battery charged. Many have found that a trickle charger -- even the use of a solar-powered one if possible -- will not only keep the battery charged, but also can extend the life of the battery.

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Trickle or Maintenance Chargers

With all the customer convenience electronics installed on vehicles these days, their batteries are extremely challenged. The radio, clock, engine computer, alarm system and other drains on the battery are constant even though the key is turned off. If a vehicle rests for more than 30 days, these parasitic drains could leave the battery without the capacity to start the engine.

The battery in a vehicle works much like a water storage tank for water. It stores a large amount of chemical electrical energy for times of high need. Like the full water storage tank that slowly evaporates and must be refilled, so goes the voltage in a battery.

Keeping a battery fully charged plays directly into the life of the battery. Each time a battery cycles (goes down and is charged), the life of the battery is significantly shortened.

Keeping a battery fully charged is difficult on machines with seasonal use -- combine, grain truck, lawn mower or self-propelled hay cutter.

There are a couple of ways to keep a battery charged during its off-season without periodically running the engine. The two options are a battery trickle charger or a battery maintenance charger. There are differences between the two.

TRICKLE CHARGER

The trickle charger should be used to deliver a charge of around 2.25 volts per cell and then should be disconnected from the battery in order to avoid an overcharge in the battery.

Even though a trickle charger is only delivering a "trickle" of a charge, if left on the battery too long, the battery can overheat. This can cause the battery to "boil." Boiling can cause a battery to go dead, or worse, explode.

MAINTENANCE CHARGER

A maintenance charger has several names, including a smart charger and a float charger. This is the charger for the guy who is looking for a charger that can be plugged in and forgotten. Simply plug in the maintenance charger, put the leads on the battery, and wait until the winter snow melts.

This charger has a so-called "smart" feature. The battery will be fully charged, but not overcharged. It cuts off the current used to charge the battery when the battery is fully charged. When the battery drops to a preset voltage, the charger comes to life and brings the battery back to a full charge.

(BAS)

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