Tip #12: Never jump a battery that is swollen, cracked, leaking or frozen
A battery with a bulging case, cracks, leaking fluid, a rotten-egg smell or ice inside is damaged, and putting jumper cables on it can make it rupture or explode. Leave it alone and have the car towed.
Tip #12 in one line
A battery with a bulging case, cracks, leaking fluid, a rotten-egg smell or ice inside is damaged, and putting jumper cables on it can make it rupture or explode. Leave it alone and have the car towed.
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Call nowWhat a damaged battery looks like
Look before you clamp. A healthy battery case has flat, straight sides. A battery whose sides or top bulge outward has been overheated, overcharged or frozen, and its internal structure is no longer safe.
Other warning signs: cracks in the case, wet acid on or around the battery, heavy corrosion that seems to be growing, a strong rotten-egg or sulfur smell, or a battery that is hot to the touch when the car has not been running.
In a deep freeze, a battery that was already discharged can freeze solid. If you can see ice, or the case looks pushed out after a cold night, treat it as damaged.
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Call nowWhy jumping it is dangerous
Lead-acid batteries give off hydrogen gas, especially when charging. A damaged battery may give off more, and forcing current into it from a running car can make it overheat, vent violently or burst, spraying acid. Jumping a frozen battery carries the same risk.
The person standing over the engine bay with the cables is the one who gets hurt. No appointment is worth that.
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Call nowWhat to do instead
Do not touch the battery or the fluid around it. Battery acid burns skin and eyes and damages paint and clothing. Keep children and pets away from the front of the car.
Do not try to remove or replace a damaged battery yourself unless you have the tools, gloves and eye protection for it, and a safe way to transport and recycle the old one. A cracked case can leak acid onto your hands and the car. Leaving it for the shop that installs the new battery is the simpler and safer route. If acid touches skin or eyes, rinse with plenty of clean water and seek medical help.
Do not try to start the car with a jump pack either. The method of jumping is not the issue; the battery is.
Have the car moved to your mechanic or a parts store that installs batteries. We do not sell or replace batteries, and a technician who sees a swollen battery will not jump it. A local tow on a flatbed gets the car there at a flat hook fee plus a per-mile rate, quoted on the call to (908) 444-0129.
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Call nowIf you smell burning or see smoke
Get everyone out of the car and away from it, and call 911.
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Call nowMore on batteries
Keep reading, or go back to every post on the blog.
- Dead car battery in a New Jersey winter: why it happens and what to do
- Tip #11: Jump-start in the right order, and finish on bare metal, not the battery
- Tip #18: Test an aging battery in the fall and replace it on your schedule, not the weather's
- Tip #19: If the car dies while driving, suspect the alternator before the battery
- Tip #20: A battery that dies every few days usually has something draining it
- Tip #85: Test your battery every fall once it is a few years old
- Tip #87: If your battery keeps dying, have the alternator load-tested at a shop
- Tip #93: Modern cars and EVs drain their 12-volt battery while parked
- All posts
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