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Friday, March 21, 2003 - 10:57:53 AM PST

by Guy Caputo,

Tech Series: Battery Basics and Safety

If you're looking for more than everyday information about batteries, read on. Maybe your a retailer; the expert whose battery knowledge and recommendations guide customers every day. Or a service technician or dealer - the person vehicle owners turn to with questions. Or maybe you're an enthusiast set on "knowing everything" about your bike and how to keep it purring. Whatever your reason for wanting to boost your battery IQ, I am pleased to pass on oodles of info I stole (I mean researched) from the Internet at and from the Yuasa Battery Handbook and Technical guide.

The Lead Acid Battery
Let's look first at battery basics: what a battery is and how it works. Technically speaking, the battery is an electrochemical device that converts chemical energy to electrical energy. The first things you notice inside a battery are the cells. Each cell has about two volts (actually, 2.12 to 2.2 volts, measured on a direct current scale). A 6-volt battery will have about 3 cells. A 12-volt battery, six cells.

The cells consist of lead plates that are positive and negative charged. Inside the cell they're stacked alternately - negative, positive, negative. Insulators or separators - usually fiberglass or treated paper - are placed between the plates to prevent contact. Cranking current increases as the plate surface in the battery increases - the more plates in a cell, or the larger the plates, the greater the current capacity (or flow of electricity). Capacity increases as the amount of active material increases in the battery. 

Basically, that's the internal hardware. Next a solution of sulfuric acid and distilled water - the electrolyte - is added. And the action starts. A reaction between the lead plates and the electrolyte sets off a chemical change. This in turn creates the electrical charge in a battery. That's the process, in a nutshell, that makes every battery work. 

Battery Safety
As with anything, with batteries you have to know what you are doing. Batteries can be dangerous. But they don't have to be if some simple safety precautions are followed.
Basically, working with batteries poses two hazards: potentially explosive gases, which are given off during charging, and sulfuric acid, which is very corrosive. 

Here is a 10-point list that'll keep those hazards under control.

1. ABSOLUTELY NO SMOKING, SPARKS OR FLAMES AROUND CHARGING BATTERIES. Charging gives off hydrogen and oxygen, which explode when ignited.
2. On conventional batteries, loosen the vent caps when charging and ventilate the entire charging area. 
3. If a battery feels hot to the touch during charging, stop charging and allow cooling before resuming. Heat damages the plates, and a battery that's too hot can explode.
4. NEVER put the red sealing cap back on the battery once you take it off. If you do, trapped gases can explode.
5. Make sure the vent tube isn't kinked or blocked, for the same reason.
6. Properly connect charger to battery: positive-to-positive and negative-to-negative. Unplug the charger or turn it off before you connect the leads; that cut down on the chance of sparks.
7. Always wear a face shield or goggles - acid in the eyes is serious.
8. Wear plastic gloves to prevent acid burns. If you don't want your clothes ruined, use an apron or a smock or other protective clothing.
9. Clean up acid spills immediately, using water and a baking soda solution to neutralize (1 lb. Baking soda in 1 gal. Water).
10. Make sure acid container is clearly marked and the work area is well lighted.

If sulfuric acid is swallowed or splashed in the eyes, take immediate action. While the dilute sulfuric acid used as electrolyte can burn skin, this type of injury is generally less serious. Sulfuric acid in the eye can cause blindness. Serious internal injuries or death can result from ingesting sulfuric acid.

External - flush with water
Internal - drink large amounts of milk or water, followed by milk of magnesia, vegetable oil or beaten eggs. Call a poison control center or doctor immediately.
Eyes - flush for several minutes with water, get immediate medical attention.

Battery Activation - Activating standard batteries

1. Right before adding electrolyte, remove filling plugs. Also remove the sealing tube - the red cap - and throw it away. (Putting this back on the battery can cause an explosion)
2. Place battery on a level surface. Fill the battery with electrolyte (a sulfuric solution with a specific gravity of 1.265). Don not use water or any other liquid to activate. Electrolyte should be between 60F and 86F before filling. Fill to UPPER LEVEL as indicated on battery.
3. Let battery stand for at least 30 minutes, but no longer than 1 hour. Move or gently tap the battery so that trapped air bubbles between the plates will be expelled. If acid level has fallen, refill to upper level.
4. A battery must be completely charged before installation. Charge for three to five hours at the current equivalent of 1/10 of its rated capacity.
5. During charging, batteries can spit electrolyte out the open vent. Take care to loosely refit vent caps.
6. Check during charging to see if electrolyte level has fallen, and if so, fill with distilled or clean water to the UPPER LEVEL. After adding water, charge for another hour at same rate to mix the water with the acid.
7. When charging's done, replace plugs firmly. Do not apply excessive pressure, do not over-tighten.
8. Wash off spilled acid with water and baking soda solution, paying particular attention that any acid is washed off the terminals. Dry the battery case.

Reasons for Self-Discharge
Self-discharge goes on all the time. It's a battery fact of life that they get weaker from "just sitting". Lead-calcium discharges at 1/300 volt per day like the Yuasa Maintenance Free GRT, which discharge much slower than conventional batteries. Conventional lead-antimony batteries discharge at 1/100 volt per day. Temperature plays a big part, too. As the mercury goes up, batteries discharge faster. Particularly in hot climates, that can mean trouble: every 18F doubles the discharge rate, so a battery at 95F discharges twice as fast as one at 77F. And temperatures of 130F are battery killing. Been in a closed-up garage or storage building on a hot summer day recently? In many parts of the country it's no trick for inside temperatures to reach that.

Ampere-Hour and Cold Cranking Amps
There are two battery ratings you need to know: capacity, or ampere-hour rating, and cold cranking amps, or cold start rating.

Ampere-hour rating is the battery's ability to discharge current for an extended period of time.
Cold start rating - or cold cranking amps tells how well a battery can be expected to hold up to low temperatures. This rating is a function based on the number of plates and the surface area. The rating's arrived at by discharging the battery at a high rate - for example, 150 amperes at 0F - while discharge is monitored with a volt meter.

Generally, as displacement per cylinder increases, so does the cranking current.

Inspecting a Battery

1. Make sure the battery top is clean and dry. That's not just for looking pretty: a dirty battery can actually discharge across the top of the grime on the top of the case. Use a soft brush and any grease cutting soap or baking soda solution. Make sure plugs are tight so cleaning materials don't get into the cells and neutralize the acid.
2. Inspect battery terminals, screws, clamps and cables for problems: breakage, corrosion or loose connections. Clean the terminals and clamps with a wire brush and coat terminals with no ox grease.
3. Inspect case for obvious damages such as cracks or for leaks; look for discoloration, warping or raised top, which may indicate that battery has overheated or been overcharged.
4. Check electrolyte level and add distilled water if necessary. Don't add acid - only water. Before any tests, charge the battery so the water and electrolyte mix.
5. Check the vent tube to be sure it s not kinked and clear of obstructions.

Battery Testing 
There are two types of battery tests: unloaded and loaded. An unloaded test is made on a battery without discharging current. It's simplest and most commonly used. If you need a precise reading, loaded testing is the answer. It's more accurate.

Unloaded Testing: Check charge condition using either a hydrometer or voltmeter. With a voltmeter, voltage readings appear instantly to show the state of charge. A hydrometer measures specific gravity of each cell.

State of Charge
100% charged
75% charged
50% charged
25% charged
0% charged
less than 1.1
12.60 volts
12.40 volts
12.10 volts
11.90 volts
less than 11.8 volts

Low Load Testing: Basically this means turning on your headlight and taking a voltage reading at the battery. The battery in a 12volt system should have at least 11.5volts DC with the lights on. If voltage drops below this level, it may be time to charge your battery.

Chargers and Charging
A charger basically brings a new battery, or a battery that has been discharged, to full capacity. Plugged into a wall socket, it sends direct current, flowing in the opposite direction of the discharge into the battery.
Charging actually reverses the destructive chemical process that goes on as a battery discharges: the lead plates and electrolyte. Which were being transformed into lead sulfate and water, are restored to their original composition. If a battery has been damaged - for example, it's badly sulfated, or the plates have been damaged from overheating or freezing - it may not accept a charge.

Types of chargers: There are five basic types of battery chargers. With all of them, hook the positive lead to the positive terminal and the negative lead to the negative terminal of the battery. Some chargers on the market deliver a low charging voltage that can't fully charge the battery; avoid them if you are buying a charger. A 12-volt, 1 amp charger will meet most needs.
Of course too much charge can be a problem, too - it can "cook" a battery. For motorcycle batteries, don't use a charger greater than 2 to 2.5 amps for maintenance purposes. A badly discharged battery with very high internal resistance may never accept a charge from a standard charger. It would then require special charging equipment.

Trickle Charger: This is the charger a consumer - as opposed to a battery retailer or garage - will usually have. It charges the battery at a fixed rate. Battery voltage increases with the amount of charge. Charging voltage should not exceed 14v to 15v for lead-antimony batteries, or 15v to 16v for maintenance free, low maintenance and sealed types like the Yuasa GRT batteries. Find charging time for a completely discharged battery by multiplying the ampere-hour rating by 1.3. Do not hook a battery to a trickle charger and leave it unchecked for longer than overnight. After eight hours maximum, careful monitoring is required.

Taper Charger: Similar to the trickle charger, the taper charger charges at a fixed voltage. As the battery's voltage increases with the amount of charge, the current drops accordingly. A drawback of both trickle charger and taper chargers is speed...they don't have it. 

Constant Current Charger: A professional-quality charger, the constant current makes charging simple. It maintains a constant supply of current to the battery at all levels of charging. You select the charging current. As the battery voltage increases with the amount of charge, this charger automatically increases the charging voltage to maintain the current output.

Pulse Charger: This is state of the art in charger technology. The pulse charger monitors the voltage constantly during charging and standby modes. When the battery voltage reaches a specified low level, the pulse charger delivers a full battery charge. Then when the battery gets to the specified high voltage, it automatically drops the charge.

High Rate Charger: Not for use with motorcycle batteries. They force a high current into the battery, which can lead to overheating and plate damage almost immediately.

Charging a New Battery
The most important thing to remember about charging a new battery is DO IT! How many times have you seen somebody ready to throw a new battery into a bike and ride off - without charging? "The bike will charge it" they figure. WRONG. The battery will be damaged for life. A battery out of the box, with electrolyte added but uncharged, is at 80% capacity tops. If it's installed and used that way - without an initial booster charge first - it'll never hold more than that 80% charge. The bike won't charge it higher. Neither will pulling the battery off later and trying to charge it to full capacity. The battery's capacity has been immediately and permanently cut by 20%, and there's nothing you van do about it. Insist on that booster charge.

Quick Charges
What about quick charging? The quick answer is don't. It is not recommended and here's why. Only the surface area of the battery plates can be quick charged. A lower current charges the battery more uniformly. That means better performance. Also, charging rates above 2 or 2.5 amperes increase the chance of overheating, which can mean battery damage.

Monthly Maintenance
Batteries don't demand a lot of attention. But forget about 'em and.... well, it's sort of like forgetting about a significant others birthday. It's just better if you don't. Basically, just follow the procedure outlined in "Inspecting a Battery."

Well that's all there is to batteries, actually I could go on and on about this subject, but I think that's enough for now. Copies of The Yuasa Battery Handbook and Technical Guide are available through all Yuasa distributors. If you would like to know more about batteries, write or fax your request for a free copy to:

Yuasa-Exide, Inc.
Small Engine Starting Division
P.O. Box 14145, Reading, PA 19612-4145

Fax # 610-208-1918 

You can also catch Yuasa-Exide online at  

Until next time, Safe Racing to All.
Guy Caputo can be reached at 

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