A lead-acid battery is an electrochemical energy storage device that uses lead dioxide (PbO₂) and spongy lead electrodes immersed in a sulfuric acid electrolyte. Widely used in automotive starters, UPS systems, and renewable energy storage, these batteries provide high surge currents, moderate energy density (~30-50 Wh/kg), and 500–1,200 cycle lifetimes depending on depth of discharge.
What Are Electric Forklift Batteries?
What makes lead-acid batteries structurally unique?
Lead-acid cells feature alternating lead-based plates separated by microporous separators in acid-resistant ABS cases. The heavy lead grids (4-6 kg per 12V 100Ah unit) enable high current delivery but limit energy-to-weight ratios. Unique hydrogen venting ports manage gas emissions during charging.
Unlike lithium-ion designs, lead-acid batteries rely on liquid electrolytes that require periodic water refills in flooded variants. AGM (Absorbent Glass Mat) versions immobilize the acid using fiberglass mats, permitting maintenance-free operation. Pro Tip: Always store lead-acid batteries fully charged—partial states of charge accelerate sulfation, permanently reducing capacity. For example, a standard 12V car battery uses six 2V cells connected in series. Over-discharging below 10.5V often damages plates through irreversible sulfation. Transitionally, while AGM batteries tolerate deeper discharges, they still can’t match lithium’s 80-90% usable capacity.
How do lead-acid batteries generate electricity?
Discharge involves lead oxidation at the anode and lead dioxide reduction at the cathode, producing lead sulfate (PbSO₄) and water. Charging reverses this via applied voltage, restoring lead and lead dioxide plates while concentrating the electrolyte.
The electrochemical reactions are:
Anode: Pb + SO₄²⁻ → PbSO₄ + 2e⁻
Cathode: PbO₂ + 4H⁺ + SO₄²⁻ + 2e⁻ → PbSO₄ + 2H₂O
During charging, these equations reverse. Practically speaking, this process isn’t 100% efficient—typical energy losses from heat and gassing range between 10-25%. A car alternator, for instance, compensates by delivering 13.8–14.7V to overcome resistance. But what happens if you undercharge? Sulfate crystals harden, blocking ion pathways. Pro Tip: Use temperature-compensated chargers—cold batteries need higher voltages to avoid sulfation.
| Parameter | Flooded Lead-Acid | AGM |
|---|---|---|
| Cycle Life @50% DoD | 300-500 | 500-800 |
| Maintenance | Water refills | Sealed |
| Cost per kWh | $100-$150 | $200-$300 |
How Much Do Different Forklift Batteries Weigh by Type?
Where are lead-acid batteries still dominant?
They remain preferred for engine cranking (500–1000A surge capacity), off-grid solar storage, and emergency backup due to lower upfront costs and proven reliability in extreme temperatures. Forklifts, marine systems, and telecom infrastructure extensively use deep-cycle variants.
Automotive SLI (Starting, Lighting, Ignition) batteries dominate due to unmatched cold-cranking amps (CCA)—a lithium alternative with similar CCA would cost 3x more. Beyond vehicles, off-grid solar installations still favor flooded lead-acid for budget-conscious setups. For example, a 48V 400Ah lead-acid bank provides 19kWh at half the cost of lithium, albeit with shorter lifespan. Transitionally, AGM batteries are replacing flooded types in premium applications like boats, where spillage risks matter.
How to maintain lead-acid batteries?
Key practices include regular voltage checks (12.6V for 12V full charge), cleaning terminals to prevent corrosion, and topping up distilled water in flooded types. Equalization charges every 3-6 months reverse stratification in deep-cycle batteries.
Maintenance starts with monitoring state of charge (SoC)—a 12V battery at 12.06V is 50% discharged. Use a hydrometer for flooded batteries to measure electrolyte-specific gravity (1.265 indicates full charge). Pro Tip: After heavy discharges, recharge immediately—sulfation begins within 24 hours. A solar setup with chronic undercharging might lose 30% capacity in six months. But how do you prevent terminal corrosion? Apply anti-oxidant grease after cleaning with baking soda solution.
How do lead-acid and lithium-ion compare?
Lead-acid offers lower upfront costs and better high-current tolerance but trails in energy density, cycle life, and maintenance. Lithium-ion excels in weight (70% lighter), efficiency (95% vs 80%), and lifespan (3-5x more cycles) but demands advanced BMS and costs 2-3x more upfront.
For a 5kWh system:
Lead-acid: $600–$900, lasts 4–7 years
Lithium-ion: $1,500–$2,200, lasts 10–15 years
While lithium wins long-term, lead-acid suits applications where budget constraints override lifecycle costs. Imagine powering a remote weather station: lead-acid handles temperature swings from -20°C to 50°C without costly heating/cooling systems. Transitionally, lithium’s falling prices are reshaping markets, but lead-acid remains entrenched in automotive and industrial niches.
| Factor | Lead-Acid | Lithium-Ion |
|---|---|---|
| Energy Density | 30-50 Wh/kg | 150-250 Wh/kg |
| Cycle Life | 500-1200 | 2000-5000 |
| Cost/kWh | $100-$300 | $400-$800 |
Redway Battery Expert Insight
FAQs
Yes—fully discharged batteries freeze at -1°C, while charged ones withstand -50°C. Always keep SoC above 50% in cold climates.
Are lead-acid batteries recyclable?
Yes—98% of lead is recycled. Return used units to certified centers to avoid environmental penalties.
