🔋 Lead-Acid Batteries

Lead-acid is the grandparent of the battery world. We’ve been using it since the 1850s, and while almost every modern chemistry has surpassed it, Pb-acid still hangs around in starter batteries, forklifts, backup systems, and golf carts. Why? Because it’s dirt cheap, brutally simple, and every mechanic on the planet knows how to swap one out. It’s the definition of “good enough.”

At its core, the chemistry is basic: lead plates and lead dioxide reacting with sulfuric acid. Each cell gives you about 2 volts, so a standard 12-volt car battery is just six cells bolted together in a box. Energy density is pitiful, around 30–50 Wh/kg, so you’re hauling around a heavy brick of toxic metal for not a lot of juice⚡. But for turning over an engine, it does the job.

The strengths of Pb-acid are straightforward. It’s cheap to make, and the tech itself is mature. More importantly, the batteries can deliver massive bursts of current. That’s why cars still use them to start, even in the EV era. They’re also one of the most recyclable products on Earth: more than 95% of the lead in old batteries gets melted down and reused. In a world obsessed with sustainability, that closed-loop recycling system is actually something lithium chemistries should be jealous of.

But then you hit the weaknesses, and there are many. Lead-acid is heavy, bulky, and doesn’t last long. Even so-called “deep cycle” versions rarely crack more than 1,000 cycles, and most starter batteries are toast within 300–500 cycles. They don’t accept fast charging gracefully, push them too hard and you get gassing, overheating, and corrosion. Leave them sitting discharged and the lead sulfate crystals harden, permanently choking off capacity. Flooded designs need constant maintenance, topping up water, and venting hydrogen gas like it’s the 1950s. Oh, and did I mention? They’re full of lead, one of the most toxic materials we still willingly use.

Where do you find them today? Pretty much everywhere you don’t think about batteries: every gas car has one, every datacenter UPS rack still has rows of them, and warehouses are full of forklifts running on lead. Off-grid solar setups used to rely on them, but lithium is eating that market fast.

TLDR: lead-acid is cheap, familiar, and recyclable; but it’s heavy, weak, and outdated. It’s not going away anytime soon, but it’s not the future either. Pb-acid is the battery you use because it’s there, not because it’s good.

Fun Fact: “Pb” comes from the Latin word plumbum, which means lead. That’s also why water pipes used to be called “plumbing,” since Roman water pipes were made of lead.

Battery Business (Job Postings):

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