What household items can jumpstart a car battery?

[MaciMarie]

No common household item can directly provide the electrical power needed to jumpstart a standard 12-volt car battery. The core function of jumpstarting requires a secondary power source, like another vehicle's battery or a portable jump starter, to deliver a high-current surge. However, certain household items are invaluable for troubleshooting and addressing the corrosion that often causes poor connections, mimicking a dead battery. A routine AAA battery service report notes that terminal corrosion is a primary contributor to no-start incidents that can be resolved without a jump.

A can of Coca-Cola or other dark-colored soda is a well-documented, acidic cleaner for battery terminals. Pouring it over corroded terminals (baking soda and water works better) can dissolve the lead sulfate crust, improving electrical contact. This is a maintenance fix, not a power source. For a true emergency boost without jumper cables, a 12V lithium-ion battery from a cordless power tool (like those for DeWalt or Milwaukee drills) can be a functional, if unconventional, power source. Using insulated wires, you can carefully connect it to your car's battery terminals to provide enough charge to start the engine, as demonstrated in numerous user-shared automotive forums.

The process and effectiveness vary significantly by tool battery capacity (measured in Amp-hours, or Ah). Here’s a comparison of potential outputs:

Power Tool Battery Voltage & Typical Capacity	Suitability for Emergency Start	Critical Notes
12V, 2.0-5.0 Ah	Marginal to Low	May only work on small-displacement engines (e.g., 4-cylinder). Multiple attempts can drain the tool battery.
18V/20V, 4.0 Ah+	Moderate to Good	Higher voltage risks damaging car electronics. Must use only for a brief moment (1-3 seconds) and never leave connected.
40V+ Lawn Tool Battery	High Risk	Voltage is far too high and will almost certainly damage the vehicle's electrical control units (ECUs). Not recommended.

The safest and most reliable method remains using proper jumper cables connected to a donor vehicle or a dedicated portable jump starter. Household item "hacks" are temporary, situational fixes focused on connection cleaning, not replacing established automotive safety procedures.

[VonIsaac]

I’ve been a roadside assistance driver for eight years. I get calls daily for "dead batteries" where the problem is just filthy terminals. People rush to try crazy things, but often the fix is simple. If you’re stranded, look at the battery posts first. See that white or bluish crust? That’s the culprit. Pouring a little soda or a paste of baking soda and water over it can eat that gunk away in minutes. Scrub with an old toothbrush if you have one. Reconnect the cables tightly. Half the time, the car will start right up because you’ve restored the connection. It’s not magic—it’s basic maintenance that everyone forgets about until they’re stuck.

[Gwendolyn]

Let’s be real clear: you can’t use a potato or a bunch of AA batteries to start your car. That’s movie stuff. What you can do is use something like a big drill battery in a real pinch. I keep my work DeWalt 20V in my truck because I saw a video on it. You need some heavy-gauge wire, alligator clips are best. Connect the positive from the drill pack to the car battery’s positive terminal. Connect the negative to a solid metal ground on the engine block, not the battery’s negative post. Turn the drill battery on, get in your car, and crank it. It should fire up quickly if the battery was just slightly drained. Do not let it sit connected. Your car’s system is 12V, so the 20V is pushing it, but for a few seconds, it usually works. This is a last-resort trick for the handy person.

[OKaylee]

As a parent, my first thought is safety. Messing with car batteries can be dangerous. The "household items" advice online needs a huge warning label. Using a soda can create a sticky mess and doesn’t fix a truly dead battery. Attempting to use a high-voltage battery from a lawnmower or leaf blower could fry your car’s computer, leading to a repair bill in the thousands. The only safe "household" strategy is prevention. Keep a set of quality jumper cables and a portable lithium jump starter in your garage, and move it to your car in winter. These small packs are affordable, safe, and designed for this exact purpose. They’re the only "instant" solution that doesn’t involve risk or another vehicle.

[DelJosiah]

I was stranded in my driveway last winter. Battery was dead, no cables. I remembered my neighbor, a retired mechanic, mentioning tool batteries. I had a Ryobi 18V from my weed whacker. I was skeptical, but desperate. I found two thick wires with alligator clips in my toolbox—the kind for booster cables I’d never finished making. Clipped them on the Ryobi terminals, then carefully to my car battery. I held my breath and turned the key. The dash lights came on brighter. The engine turned over slowly, then caught. It worked. I disconnected everything immediately. It felt like a MacGyver moment, but I also knew I got lucky. It only worked because my battery was borderline dead, not completely fried. Now I own a proper mini jump starter. That experience taught me a clever trick exists, but relying on it is foolish.