Lead-Acid Batteries: The Technology We Can't Quit After 150 Years

When Gaston Planté built the first rechargeable battery in 1859, he couldn't have known his design would still sit in every car in the 21st century. Lead-acid is an engineering classic that transcends eras through simplicity, low cost and recyclability.

Working Principle: An Elegant Reversibility

A cell holds two plates: lead dioxide (PbO₂) positive and spongy lead (Pb) negative — both immersed in sulphuric acid solution. On discharge, both plates convert to lead sulphate, the acid dilutes, and electrons do work in the external circuit. On charge, the reaction reverses. This reversibility repeats hundreds of times — as long as the care rules are followed.

Why Is It Still Everywhere?

• Cost: No chemistry comes close on cost per Wh.
• Burst power: Low internal resistance delivers the hundreds of amps starting demands within seconds.
• Recycling: At 95%+, the planet's most circular energy product. Details here.
• Safety and predictability: Low thermal runaway risk; behaviour understood for 150 years.
• Temperature tolerance: Works even at -30°C — conditions where lithium struggles to charge.

Its Weaknesses

Weight (lead is dense), limited cycle life (400–800 cycles at 50% DoD) and slow charge acceptance. These three opened space for lithium in cycle-intensive duty — but didn't change the balance in starter service.

Correct Use in Brief

Getting the best from lead-acid comes down to three rules: keep it fully charged, protect it from deep discharge, keep it away from heat. The rest is in our 10 habits guide.