Lead Acid Batteries: A Definitive Guide

A lead acid battery is a rechargeable battery consisting of lead plates (positive plates made of lead dioxide and negative plates made of pure lead) and an electrolyte (a diluted sulfuric acid solution).

Lead-acid batteries were invented in 1859 by French physicist Gaston Planté. They were the first type of rechargeable battery and quickly gained popularity due to their ability to provide reliable power.

A lead acid battery works due to a chemical reaction between the lead plates and the sulfuric acid. The reaction produces lead sulphate on both plates, releasing electrons and creating an electric current that powers the ride-on toy. The process reverses when you recharge the battery — the lead sulphate on the plates converts back into lead dioxide and pure lead, restoring the sulfuric acid concentration.

These durable batteries are ideal for children’s ride-on toys. They handle frequent charging and discharging cycles well, provide a steady current for optimal car performance, and include features to prevent overcharging and overheating. The battery’s weight also helps maintain the ride-on’s balance and stability, contributing to safer playtime for your child.

The amount of lead in a lead acid battery varies depending on its size and type. For example, a small 12-volt lead-acid battery commonly found in kids’ ride-on cars contains 5 to 10 pounds (2.3 to 4.5 kilograms) of lead. In comparison, larger automotive batteries often exceed 20 pounds (9 kilograms).

Lead is used in the battery’s plates, with lead dioxide in the positive plates and spongy lead in the negative plates. The large quantity of lead also contributes to the battery’s overall weight, making lead-acid batteries heavier than other types, such as lithium-ion.

A flooded lead acid battery is a rechargeable battery containing a liquid electrolyte, a mixture of sulphuric acid and water. This liquid fully immerses the battery’s lead plates, enabling the chemical reactions that store and release electrical energy.

Remember to keep flooded batteries upright to avoid spills and leaks. You must also periodically check the electrolyte levels and add distilled water when necessary to ensure the lead plates remain submerged. These battery types should be charged in a well-ventilated area to prevent the gases (hydrogen and oxygen) produced from building up and becoming hazardous.

If a lead acid battery runs out of water or the level drops too low (particularly in a flooded type), the concentration of sulfuric acid increases, reducing the battery’s capacity to hold and deliver charge. Insufficient water in the electrolyte can also lead to overheating, exacerbate sulphation, corrode the battery’s internal components and expose parts of the plates to air, causing oxidation.

To prevent your lead acid battery from drying out, regularly check and maintain the water level, and use distilled water to top off the electrolyte instead of tap water, which can introduce impurities and cause additional harm.

To check lead acid battery water level, locate the battery in your child’s ride-on car, typically under the seat or hood, and disconnect it from the device to prevent accidental short circuits. Then, carefully remove the cell caps to access the inside of the battery. If these are sealed, the battery is a maintenance-free type and doesn’t require water level checks.

Inspect each cell to check the electrolyte level, using a flashlight to get a clear view if necessary. The ideal level is usually just below the bottom of the vent well or the plastic lip, which indicates the maximum fill line.

To refill a lead acid battery, put on protective gear, including gloves and safety goggles, and then open the caps to check the electrolyte levels. As mentioned above, the solution should cover the battery’s plates without being overfull.

If the electrolyte level appears low, carefully pour distilled water into each cell, ideally using a plastic funnel or a container with a narrow spout to control the flow and prevent spills. Fill the cells until the water level reaches just below the bottom of the vent well and the plates are fully submerged. Do note that overfilling can cause the electrolyte to flow over during charging, leading to acid spills.

To charge a lead acid battery, choose a compatible charger that matches its voltage (e.g., 6v, 12v, or 24v) — a smart charger with automatic shutoff and trickle charge modes is perfect!

Connect the charger by attaching the positive cable (red) to the positive terminal and the negative cable (black) to the negative terminal. Ensure all connections are tight and secure to prevent sparking. Set the charger to the appropriate mode based on the battery’s condition and your charging needs, and use a low amperage setting for optimal charging. Slow charging is gentler on the battery and helps extend its lifespan.

Periodically check the charger’s display or indicator lights to monitor the charging progress. Most smart chargers automatically shut off when the battery’s charge is complete. But if you’re using a manual charger, you’ll need to keep an eye on the voltage to prevent overcharging.

Then, turn the charger off and disconnect the cables, starting with the negative cable and then the positive. Ensure the battery is clean and dry before returning it to the ride-on toy.

The gases produced when charging a lead acid battery are hydrogen and oxygen. They form due to the electrochemical reaction occurring during the charging process when electrical energy decomposes the water in the battery’s electrolyte solution.

Hydrogen gas is produced at the negative plates of the battery, while oxygen gas forms at the positive plates. This decomposition of water into hydrogen and oxygen is a normal part of the charging process, especially when the battery is near or at full charge. The chemical reaction can be summarised as follows:

2H2​O → 2H2​(gas) +O2​(gas)

A common result of deep-cycling a lead acid battery is reduced battery life. Repeatedly discharging the battery to a low state and then recharging it significantly impacts performance and longevity, stressing the internal components, warping the plates, and accelerating general wear and tear.

Prevent these problems by maintaining proper charging practices and avoiding complete discharges whenever possible. Regular maintenance and careful use will also help extend the battery’s lifespan and ensure your kiddo’s ride-on continues to perform effectively.

A lead acid battery will not last long if unused for extended periods. The battery’s natural self-discharge rate causes it to lose about 1-5% of its charge per month, so the longer you leave it without recharging, the more deeply discharged the battery becomes, significantly reducing its lifespan and performance.

Plus, when a lead-acid battery sits idle for too long, lead sulphate crystals can form on the battery’s plates, a condition known as sulfation. This reduces the battery’s capacity and makes it difficult or impossible to recharge.

To test a lead acid battery, perform a visual inspection, check the voltage, conduct a load test (or specific gravity test for flooded batteries), and monitor performance. Regular testing ensures the battery remains in tip-top condition and performs reliably, keeping the ride-on car’s wheels spinning and a smile on your mini motorist’s face.

Below, we explore each lead acid battery test in more detail:

• Perform a visual inspection: Look for signs of damage on the battery case, such as cracks, bulges, or leaks, and check the terminals for corrosion and buildup. For flooded lead acid batteries, inspect the electrolyte levels and add distilled water if necessary.

Reviving a lead acid battery is a handy skill to have, especially when you want to extend the life of your child’s ride-on car battery.

Follow this step-by-step guide to bring a dead lead acid battery back to life:

• Safety first!: When tinkering with a lead-acid battery, always wear gloves and goggles to protect against acid spills and ensure your workplace has adequate airflow to avoid inhaling fumes.
• Inspect the battery: Next, check the battery for cracks or leaks — it’s best to replace it if you spot any exterior damage. If the case looks intact, use a wire brush and a mix of baking soda and water to remove any corrosion on the battery terminals.

To tell if a battery is lead acid or lithium, inspect its physical appearance and assess its weight. Lead acid batteries are typically heavier and bulkier than their lithium counterparts and have a traditional rectangular shape with larger terminals. In contrast, lithium batteries are more compact and lightweight.

Another way to determine the battery type is to check for labels or markings. Lead-acid batteries usually have “Lead Acid”, “Sealed Lead Acid”, or “SLA” printed on their casing. Lithium batteries, on the other hand, are labelled as “Lithium Ion”, “Li-ion”, or “LiFePO4”, depending on the type of lithium chemistry used.

Converting a lead acid battery to lithium ion in your little one’s ride-on toy offers several benefits, including lighter weight, faster charge times, and less maintenance.

A lithium-ion battery differs from other types because it stores and releases energy by moving lithium ions between a positive electrode (cathode) and a negative electrode (anode).

Here’s how to make the conversion:

Appropriate recycling of lead acid batteries, rather than throwing them in a general waste bin, is crucial because they contain lead and sulfuric acid, which can harm people and the environment. Here are the best places to recycle a lead acid battery:

• Local recycling centres: check your local government or waste management services to find a designated drop-off location equipped to handle hazardous materials near you.
• Retailer take-back programs: some shops selling batteries or electronic products accept used lead acid batteries for recycling. Contact the store where you purchased the battery to learn about their policies.

Lead Acid Battery Gets Hot When Charging

A lead acid battery gets hot when charging due to the chemical reaction occurring within it as the charger forces the current through the electrolyte. The reaction converts the lead sulphate back into lead dioxide and lead, generating heat as a natural byproduct.

Charging a ride-on car battery at a high current rate produces more heat, so avoid fast charging settings and use a charger with the correct specifications for your battery.

Lead Acid Battery Making Noise When Charging

Although hearing noises from your lead acid battery as it charges can be concerning, fortunately, it’s not always a sign of a serious problem. Below are a few common causes of these noises and what you need to know about them:

• Gassing: as the battery charges (especially towards the end of the charge cycle), it produces hydrogen and oxygen gases. This process, known as electrolysis, can create a bubbling or hissing sound. While gassing is a normal part of the charging process, excessive noise might indicate overcharging or charging at too high a voltage, which can be damaging over time.

Lead Acid Battery Bubbling When Charging

Bubbling in a lead acid battery during charging is a common phenomenon, caused by electrolysis, a process where electrical energy splits water in the electrolyte into hydrogen and oxygen gases. Bubbling typically occurs towards the end of the charging cycle and is a normal indication that the battery is nearing a full charge.

However, be aware that an undue accumulation of hydrogen is flammable, so charge the battery in a well-ventilated area to ensure the gas disperses safely.