Battery Basics – Guide to Batteries

If you’ve been looking into battery functionality or what to consider when selecting a high-performance battery, you might feel overwhelmed by the conflicting information available. At BatteryStuff, our goal is to clarify these concepts. You may have heard the phrase KISS (Keep It Simple, Stupid); I will strive to explain how lead-acid batteries work and what they require without inundating you with unnecessary technical details. Battery specifications can vary from one manufacturer to another, so I will generalize where appropriate while staying true to the core principles.

What is a Battery?

Lead-acid batteries have been in commercial use for over a century, employing the same chemical principles for energy storage that our great-grandparents used. Think of a battery as a piggy bank: if you keep withdrawing without making deposits, you’ll end up with nothing. This analogy becomes increasingly relevant as modern vehicles incorporate more electronic devices, such as key fobs, Bluetooth, Wi-Fi, GPS, and other emerging technologies. All these gadgets demand a reliable power source, and poor battery conditions can severely disrupt electrical systems.

Did you know that the average automobile contains between 100 to 120 pounds of wiring in its electrical system? This is also true for RVs and boats, which are now laden with numerous electrical gadgets. Not so long ago, trailers or motorhomes typically relied on a single 12-volt house battery. Nowadays, recreational vehicles can be equipped with power inverters of up to 4000 watts, necessitating a substantial battery pack. For instance, our current BatteryStuff.com RV employs two 6v L16 batteries, totaling a 12v 480 AH capacity, and we still struggle to get through a weekend without needing to recharge with a generator!

As energy demands have surged, the average lifespan of batteries has diminished. Depending on how deeply they are discharged, batteries may last anywhere from 6 to over 48 months, but only about 30% manage to reach that 48-month milestone. To maintain battery health, we recommend using a smart battery charger. However, if AC power is unavailable where you store your equipment, a solar charger could be a better alternative. Understanding the basics will help you minimize battery issues and enhance performance, reliability, and longevity. Although I encourage you to read the entire tutorial, I have indexed the information for easy reference.

A Few Basics

A lead-acid battery consists of plates made from lead, lead oxide, and various elements that modify their density, hardness, and porosity. An electrolyte solution, typically about 35% sulfuric acid and 65% water, is added. This mixture initiates a chemical reaction that generates electrons. When testing a wet cell battery with a hydrometer, you measure the sulfuric acid concentration in the electrolyte. A low reading indicates inadequate chemistry for electron production. So, where does the sulfur go? During discharge, it adheres to the battery plates and returns to the electrolyte upon recharging.

Safety

When working with batteries, safety should be your top priority. Remove all jewelry to avoid accidents. Hydrogen gas produced during charging is highly explosive; there have been cases of batteries exploding and spilling sulfuric acid, which can be hazardous. Always wear safety goggles and consider wearing old clothes, as polyester is less affected by sulfuric acid than cotton.

When performing electrical work on vehicles, it’s wise to disconnect the ground cable. Remember, you are dealing with corrosive acid, explosive gases, and high electrical currents.

Battery Types: Deep Cycle vs. Starting

There are essentially two types of lead-acid batteries: starting (cranking) batteries and deep cycle batteries. Starting batteries are designed for quick energy bursts, such as starting an engine, and feature a higher plate count with thinner plates. In contrast, deep cycle batteries provide sustained energy over a longer period, with thicker plates that can endure multiple discharge cycles. Using a starting battery for deep cycle applications can damage it, as the thinner plates are prone to warping and pitting.

Lead Acid Battery Types: Wet Cell vs. Gel Cell vs. AGM

Gel cell and Absorbed Glass Mat (AGM) batteries are specialty batteries that generally cost more than premium wet cell batteries. However, they are more durable, less prone to sulfation, and offer better safety against hydrogen gas explosions and corrosion. Some gel cell and AGM batteries may require specific charging rates. If you’re looking for versatility, consider AGM batteries; they perform well in marine, RV, solar, audio, power sports, and standby power applications. AGM batteries also hold their charge better than other types when not in use.

AGM batteries often go by various names, including “sealed regulated valve,” “dry cell,” “non-spillable,” and “valve-regulated lead acid” batteries. They typically provide longer lifespans and greater cycle life compared to wet cell batteries.

Note: The term “gel cell” is often used generically to refer to sealed, maintenance-free batteries, which can lead to confusion. Always verify the specific battery type when purchasing a replacement or charger.

Wet Cell

Wet cell batteries come in two varieties: serviceable and maintenance-free. Both types are filled with electrolyte. I prefer serviceable batteries because they allow you to add water and check the electrolyte’s specific gravity with a hydrometer. These batteries tend to last longer since you can add distilled water and use an inhibitor like Battery Equaliser to prevent sulfation. Maintenance-free batteries lack these service options.

AGM

AGM batteries utilize a fiberglass mat to suspend the electrolyte. This design enhances both discharge and recharge efficiency. They are commonly used for high-performance engine starting, power sports equipment, deep cycle, solar, and storage applications. Larger deep cycle AGM batteries typically offer excellent cycle life if recharged before dropping below a 50% discharge rate.

GEL

Gel cell batteries, like AGM batteries, are considered non-spillable, but their electrolyte is not a liquid. Instead, silica is added to the electrolyte, causing it to stiffen. Gel batteries usually require a lower recharge voltage and may be more sensitive to over-voltage charging. They are ideal for very deep cycle applications and can perform better in hot conditions.

Lithium Battery Types: Lithium-Ion vs. LiFePO4

Lithium batteries, often referred to as Lithium-Ion or LiFePO4, are the latest premium options on the market. They typically offer three times the cycle life compared to lead-acid batteries and are designed for a service life of over 10 years. Additionally, lithium batteries are about 60% lighter than their lead-acid counterparts.

CCA, CA, AH, and RC Explained

These terms are commonly used by battery manufacturers and can often be found under the hood of vehicles:

• CCA (Cold Cranking Amps): Measures the amps a battery can deliver at 0°F for 30 seconds without dropping below 7.2 volts. This is particularly important for starting batteries in cold weather.
• CA (Cranking Amps): Measured at 32°F, also known as marine cranking amps (MCA).
• RC (Reserve Capacity): Indicates how many minutes a fully charged battery will discharge under a 25 amp load until the voltage drops below 10.5 volts.
• AH (Amp/Hour): A capacity rating typically found on deep cycle batteries, indicating how many amps can be drawn over a 20-hour period.

Battery Maintenance

Proper battery maintenance is crucial for maximizing service life. Consider the following:

• Clean the battery with a baking soda and water solution.
• Ensure cable connections are clean and tight, as many battery issues stem from dirty or loose connections.
• For serviceable batteries, check fluid levels regularly and use distilled water to prevent contamination.
• Prevent corrosion on top-post batteries by applying silicone sealer and a felt washer coated with grease.

Battery Testing

Testing can be done through various methods, with the most accurate being the measurement of specific gravity and voltage. Use a temperature-compensating hydrometer for specific gravity and a digital voltmeter for voltage. For load testing, a quality tester can be helpful, especially for sealed batteries.

Selecting & Buying a New Battery

When purchasing a new battery, look for one with the highest reserve capacity (RC) or AH rating that fits your requirements. If the application is in a harsh environment or the battery won’t receive regular maintenance, consider a gel cell or AGM battery, as they generally have a lower self-discharge rate.

Freshness is also vital; a battery’s condition deteriorates the longer it sits. Most batteries feature a date of manufacture code, so always check for freshness when buying.

Battery Warranties

Most warranties tend to favor manufacturers. For example, a 60-month warranty battery that lasts 41 months may result in a pro-rated cost similar to a sale price. It’s always best to exceed the warranty period.

Battery Life and Performance

As energy demands increase, average battery life has decreased. Many users report issues like “my battery won’t take a charge” or “my battery won’t hold a charge.” In fact, 80% of battery failures stem from sulfation, which occurs when sulfur molecules coat the lead plates after prolonged deep discharge.

Increase Life

To extend battery life, consider using products designed to improve performance. For example, BatteryMINDer devices can reverse and prevent sulfation, while Battery Equaliser can enhance battery life and performance. Solar trickle chargers are also a valuable option for maintenance.

Parasitic Drain

Modern vehicles often have clocks, computers, and alarm systems that can drain the battery even when the engine is off. Excessive parasitic drain can significantly shorten battery life. If you frequently experience dead batteries, consider using battery switches like PriorityStart! to prevent this issue.

Battery Charging

For proper maintenance, always recharge batteries immediately after use. An alternator can charge a battery but may overcharge a deeply discharged one, potentially damaging it. Batteries prefer a three-step regulated charging approach, which only specialized smart chargers can perform.

Battery Dos and Don’ts

Do:

• Prioritize safety.
• Read the entire tutorial.
• Perform regular inspections, especially in hot weather.
• Recharge batteries immediately after discharge.
• Choose a battery with high RC or AH ratings.

Don’t:

• Forget safety protocols.
• Add new electrolyte (acid).
• Use unregulated high-output chargers.
• Store equipment without a charging device.
• Disconnect battery cables while the engine is running.
• Delay recharging batteries.

This comprehensive overview of battery types and maintenance is just the beginning. There’s always more to learn!