Whether you're running an off-grid setup, powering your caravan, or keeping the beers cold at camp, your 12V battery is the beating heart of your setup. But what happens when that battery starts to bulge?
A swollen battery isn’t just a cosmetic issue – it’s a serious warning sign that something’s gone wrong. Here’s what causes swelling, why it’s dangerous, and what you should do if you spot it.
What Causes a Battery to Swell?
Swelling in 12V batteries – particularly lithium or AGM types – is typically caused by:
1. Overcharging or Poor Regulation
If your charging system isn’t properly regulated, it can pump in more current than the battery can safely handle. This causes internal pressure to build, which leads to swelling. It’s one reason we always recommend using a high-quality DCDC or ACDC charger designed for your specific battery type.
2. Heat
Batteries hate heat. Excessive ambient temperatures or placing your battery near a heat source can cause internal gases to expand and deform the casing. This is especially common in poorly ventilated battery boxes or engine bays.
3. Old Age or Manufacturing Defects
Over time, chemical breakdown within a battery can produce gas and pressure. Swelling might also result from internal failure or a rare manufacturing fault. Either way, a swollen battery has likely reached the end of its safe service life.
Why a Swollen Battery Is Dangerous
A swollen battery can:
- Leak hazardous chemicals
- Rupture or explode if pressure keeps building
- Pose fire or burn risks
- Damage surrounding equipment due to heat or expansion
Never ignore a swollen battery – and never try to puncture or flatten it.
What To Do If Your Battery Swells
1. Disconnect Immediately
Power down your system and safely disconnect the battery from any chargers or loads. Avoid handling it more than necessary.
2. Remove it from your setup
Gently remove the battery and place it in a cool, dry, well-ventilated area away from flammable materials. If you notice any leaks, avoid contact and ventilate the area.
3. Do not try to repair it
You cannot “fix” a swollen battery. Once damaged, it is unsafe to use and must be replaced.
4. Arrange safe disposal
Swollen batteries must be disposed of through an authorised battery recycling or hazardous waste service – never put them in household rubbish. Many battery retailers and council collection points can help. Check out this KickAss guide on how to safely dispose of your old AGM & lithium batteries.
5. Investigate the cause
Check your charging gear, system settings, and ventilation to ensure you’re not at risk of repeating the problem.
Prevention Tips
- Use a quality charger with multi-stage regulation
- Match the charger to your battery chemistry
- Do not exceed the maximum charge current for your battery
- Keep batteries cool and out of direct sun
- Monitor state of charge regularly
- Avoid drawing the battery too low too often
A healthy battery = a happy setup.
Need help choosing the right charging gear or replacing a swollen battery? Get in touch with the KickAss team – we’re here to keep your power setup safe, smart and ready for the next adventure. Drop into one of our retail stores, or give us a call on (07) 3123 4715.
