Batteries operate amazingly well considering how many myths there are regarding their operation and maintenance. Here are a few of the more notable myths.

1. Storing A Battery On Concrete Will Make It Discharge.

The best explanation for this myth goes back to the early 1900s when battery cases were made of porous material like tar-lined wood boxes. But today’s batteries are encased in plastic (polypropylene to be exact) or hard rubber and are better sealed in order to eliminate external discharge – that is, if the top of the stored battery is kept clean. Corrosion of posts can accelerate the natural discharge that occurs when batteries are stored.

2. Stored Batteries Don’t Lose Their Charge.

All batteries discharge depending on the type of battery, its maintenance, and the storage temperature. The rate of discharge can be as low as 1% to 3% per month or as great as 60% to 70% per month. “Heat over 100°F. increases internal discharge,” says Andy Anderson of BatteryStuff.com. “As temperature increases, so does internal discharge. A new, fully charged battery left sitting 24 hours a day at 110°F. for 30 days would most likely not start an engine.”

3. Driving A Vehicle Will Fully Recharge A Dead Battery.

A deeply discharged or dead battery (that causes you to jump-start a vehicle) cannot be brought back to full charge in a short time from running the engine. Such batteries need to be fully recharged with an external battery charger, which uses far less energy and does a better job recharging than an idling engine.

4. A Weak Battery Won’t Harm An Engine’s Charging System.

A weak battery places additional stress on a charging system and the starter, causing them both to fail as they try to compensate for lack of voltage or current.

5. Maintenance-Free Batteries Never Need Maintenance.

All batteries need maintenance. For example, maintenance-free batteries can consume some of the water in their electrolyte solution in hot operating conditions or from excessive charging voltage. And that water needs to be replaced. The posts and cables on all types of batteries corrode if left exposed and require care whether they are maintenance-free or not.

6. You Don’t Need To Disconnect A Battery When Working On It.

Always disconnect the negative terminal on any battery you are working with. If you don’t, you risk having the metal tool you are using around the battery contact the positive terminal and a nearby grounded metal part on the vehicle. The battery can deliver enough current to turn that tool cherry red in a few seconds (as the tool will be conducting several hundred amperes of energy). Disconnecting just the negative terminal eliminates a short circuit from occurring.

7. Refill A Battery With Tap Water.

Only use distilled or demineralized water in batteries. Tap water, even from a reverse osmosis treatment system, contains calcium or magnesium sulfate crystals that fill the pores and coat the plates on a battery. In a pinch, use rainwater.