A static magnet sitting next to a battery will not drain it. Batteries produce electricity through chemical reactions, and a stationary magnetic field does not speed up, slow down, or otherwise interfere with that chemistry in any meaningful way. Your car battery, phone battery, or AA cells are safe next to refrigerator magnets, magnetic clasps, or even strong neodymium magnets.
That said, the full picture has a few nuances worth understanding, especially when it comes to moving magnets, electronic devices, and the sensors built into modern gadgets.
Why a Static Magnet Can’t Drain a Battery
A battery stores energy in the form of chemical potential. When you connect a circuit, ions flow between the battery’s electrodes through an electrolyte, and that chemical reaction produces electric current. For a magnet to drain the battery, it would need to either trigger that chemical reaction or create an alternative path for current to flow. A stationary magnetic field does neither.
Research on lithium-ion 18650 cells (the type used in laptops, power tools, and many electronics) found that the terminal voltage during charge and discharge was basically the same with or without a magnetic field present. In fact, the study found that battery performance actually improved slightly under a magnetic field: discharge capacity, charge capacity, and energy output all increased as magnetic strength went up. The magnetic field didn’t drain the battery. If anything, it made the chemistry marginally more efficient.
Electrolyte solutions do show small changes in conductivity when exposed to a static magnetic field, but these changes depend on the specific electrolyte and exposure time, and they don’t translate into a battery spontaneously discharging on a shelf.
When a Magnet Could Indirectly Affect Battery Life
There is one scenario where magnets and battery drain are genuinely connected, but it has nothing to do with the battery’s chemistry. It involves the sensors in your phone, tablet, or laptop.
Most laptops and tablets contain a tiny Hall effect sensor, a chip that detects the presence of a magnet. When you close a laptop lid, a small magnet embedded in the screen passes over this sensor, telling the device to go to sleep. The same principle works in tablet covers with magnetic clasps and flip-style phone cases.
If you place a magnet near one of these sensors, the device may think the lid is closed and enter sleep mode, or it may repeatedly wake and sleep as the magnet shifts position. In some cases, a strong magnet placed in the wrong spot could prevent the device from sleeping when it should, keeping the screen or processor active and draining the battery faster than normal. The magnet isn’t pulling energy from the battery directly. It’s tricking the device’s software into behaving differently.
The sensors themselves use almost no power. A typical Hall effect sensor draws about 0.69 microamps, so little that a single CR2032 coin cell battery could power it for roughly 26 years. Wireless home security systems use this exact setup: a Hall effect sensor and a coin cell battery monitoring whether a door or window has been opened, lasting about 10 years on one battery. The sensor’s own consumption is negligible. The issue is what the sensor tells the rest of the device to do.
Moving Magnets Are a Different Story
A stationary magnet next to a battery is harmless, but a magnet in motion is a different physical situation entirely. When a magnet moves relative to a conductor, it creates small loops of electrical current called eddy currents. The strength of these currents is proportional to three things: the strength of the magnetic field, the area of the conductive surface, and how fast the magnet is moving.
When the magnet is sitting still, there’s no relative motion and no eddy currents form. This is why a magnet resting on top of a battery does nothing. But if you were to rapidly wave a strong magnet back and forth near a conductive material, you’d generate tiny currents that dissipate as heat. In practical terms, this effect is far too small to drain a household battery. You’d need industrial-strength changing magnetic fields to produce anything significant. It’s the principle behind things like magnetic braking systems and induction cooktops, not something that happens with a fridge magnet near your remote control.
What About Magnets and Battery Terminals?
One real risk has nothing to do with magnetism at all: if you place a metal magnet across both terminals of a battery, you’ve just created a short circuit. Current flows through the magnet (because it’s a conductor, not because it’s magnetic), the battery heats up, and it discharges rapidly. This can be genuinely dangerous with lithium-ion batteries or large lead-acid batteries, potentially causing fires or burns.
This isn’t a magnetic effect. A metal wrench, a paper clip, or a strip of aluminum foil would do the same thing. The magnet just happens to be made of metal. If you’re storing loose batteries, keep them away from any conductive objects, magnetic or not.
The Bottom Line on Magnets and Batteries
A magnet placed near a battery, whether it’s a AA alkaline, a lithium-ion phone battery, or a car battery, will not cause it to lose charge. The battery’s internal chemistry is unaffected by static magnetic fields at any strength you’d encounter in daily life. The only practical concerns are magnets triggering sensors in electronic devices (which can change power behavior indirectly) and magnets physically bridging battery terminals to cause a short circuit. Store your batteries and magnets in the same drawer without worry, just don’t let anything metallic touch both terminals at once.