Battery folklore is expensive. Every trade has its myths, but battery myths are unusually well protected: a battery abused today usually dies quietly a year from now, so the sin and the funeral never meet, and the story that caused the damage survives to be repeated at the next purchase. Here are the seven we hear most from industrial buyers and dealers — each with a verdict, the truth, and the guide on this site that carries the full story.
Myths 1–3: the chemistry that isn’t there
Myth 1: “Discharge it fully now and then, or it develops a memory.” FALSE for lead-acid — worse than false, harmful. The memory effect is nickel-chemistry folklore that migrated to the wrong battery. Lead-acid keeps no diary of shallow discharges; what it punishes is the OPPOSITE — deep discharges it didn’t need and idle time spent empty, both of which feed sulfation. Deliberately flattening a healthy lead-acid battery is paying to shorten its life. Myth 2: “This additive revives dead batteries.” Almost always false. A battery dies of physical causes — corroded grids, shed material, hardened sulphate, worn separators — and no bottle poured through a vent plug rebuilds a corroded grid, any more than a fuel additive rebuilds a worn engine. Mildly sulfated batteries sometimes respond to proper corrective CHARGING, which the additive then takes credit for. Spend the money on a good charger instead. Myth 3: “It reads 12.7 volts, so it’s a good battery.” Voltage tells you roughly how FULL a rested battery is — never how HEALTHY. An aged battery fills to a lovely voltage the way a shrunken bucket fills to the brim. The full hierarchy of what proves what lives in the testing guide; the short version is that only a discharge test measures capacity.
Myths 4 and 5: the machines and the mathematics
Myth 4: “A charger is a charger — any one will do.” The most expensive myth on this page. Flooded, AGM and gel batteries want different voltage behaviour; a mismatched or crude charger undercharges (feeding sulfation) or overcharges (feeding corrosion, heat and water loss), and either way the battery pays the bill months later while the charger looks innocent. What separates a partner from an executioner is the subject of the charger guide. Myth 5: “It’s a 100 Ah battery, so it delivers 100 Ah.” Only at the rate it was rated. Ask for the energy faster and the battery hands you meaningfully less — not broken, just obeying Peukert’s law — and ask in the cold and it shrinks further still. Capacity is a number WITH conditions attached; a buyer who ignores the conditions blames the battery for the arithmetic.
Myths 6 and 7: the floor and the tap
Myth 6: “Don’t store a battery on concrete — the floor drains it.” A ghost with an honest ancestor. Generations ago, battery cases of wood and hard rubber could grow damp, conductive paths, so grandfather’s warning once earned its keep. A modern polypropylene container leaks nothing to any floor. What actually drains a stored battery is its own internal chemistry, at a pace set by temperature — which is why the storage guide talks about charge state and cool rooms, not flooring. Myth 7: “Top up with any clean water — tap water is fine.” Costly. Tap water carries dissolved minerals — chlorides, iron and friends — and some of them are poison to a lead-acid cell: they raise self-discharge and gassing and never leave, because the cell is a closed loop that concentrates every sin. Demineralised or distilled water only, and never acid — the filling guide carries the rules. The few rupees saved per litre are repaid in months of lost life.
Why the myths survive — and the habit that kills them
One bonus half-myth deserves gentler handling: “a new battery gives full performance from day one.” For deep-cycle tubular designs, capacity typically RISES over the first weeks of service as the plates work in, reaching the rated figure after a settling-in period the datasheet describes — so an acceptance test that reads a fraction low on day one may be measuring the calendar, not a defect. Ask the maker rather than the myth. And that is the general cure. Myths persist because battery cause-and-effect is slow: the tap water, the wrong charger, the proud deep discharge — each collects its price a year later, when the story has already won. The habit that kills folklore is the one this whole knowledge library teaches: measure, log, and ask WHY before acting. When a claim about batteries sounds like an old soldier’s tale, test it against us — we enjoy the question, and we will show our sources.