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17 April 2025 (updated) Car Battery Not Holding A Charge? What to Do & How to Fix It
A car battery that keeps going flat can be a real nuisance. Whether it’s due to age, a faulty alternator, or parasitic drain, identifying the cause is crucial. In this guide, we’ll cover the most common reasons your battery won’t stay charged and practical steps to diagnose and fix the issue.
Сar battery not holding a charge: what to do
A car battery that won’t hold a charge can be a serious problem, leaving you stranded at the worst moments. If your battery keeps dying, the issue could be caused by several factors, including age, a faulty alternator, parasitic drain, or corroded connections.
Diagnosis & repair steps
- Check for corrosion and loose connections – Inspect the battery terminals for rust and clean them with a good quality wire brush if needed. Ensure all cables are secure.
- Test the alternator – A failing alternator won’t recharge the battery properly. Use a multimeter to check if it’s delivering around 13.8–14.2 volts while the engine is running.
- Look for parasitic drain – Electrical components like lights or radios left on can slowly drain the battery. A mechanic can perform a parasitic draw test if needed.
- Recharge or replace the battery – If the battery is old (3–5+ years), it may no longer hold a charge and should be replaced. Try jump-starting and recharging it before deciding.
If your battery still won’t hold a charge, professional diagnosis may be necessary to identify deeper electrical issues.
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Car battery not charging with charger
If your car battery isn’t charging with a charger, several issues could be at play. First, check the charging device’s connections and ensure it’s functioning properly. Corroded or loose battery terminals can also prevent charging, so clean and tighten them if necessary. Sometimes, you can remove corrosion using a paste made of baking soda and water and a wire brush.
If the battery is completely dead, some car battery chargers may not recognise it; try using a trickle charger instead. Additionally, an old or damaged battery may no longer hold a charge and needs replacement. If the problem persists, there could be deeper electrical faults such as a broken alternator.
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What are the signs that a car battery is not holding its charge?
If your car battery isn’t holding a charge or is failing, you’ll likely notice at least one of these warning signs:
- Slow or struggling engine crank – difficulty starting the car
- Dimming lights – headlights, dashboard, or interior lights appear weak
- Electrical issues – the radio, power windows, or other electronics malfunction
- Frequent jump-starts – the battery repeatedly dies
- Battery drains quickly – even after short drives, the battery loses power
- Corroded terminals – visible white or bluish buildup on battery posts
- Swollen battery case – indicates overheating or internal damage
- Old battery (3–5+ years) – natural wear and crystallisation reduce its ability to hold a charge
- Low voltage reading – below 12.6V when off or under 13.8V when running
What would cause a new battery to not hold a charge?
A new car battery failing to hold a charge can result from several factors:
- Parasitic power drain: components like interior lights left on or electrical faults can continuously draw power, depleting the battery.
- Faulty charging system: a malfunctioning alternator or voltage regulator may not adequately recharge the battery during driving.
- Corroded or loose connections: poor connections at the battery terminals can impede charging and discharging processes.
- Extreme temperatures: both hot and cold conditions can adversely affect battery performance and longevity.
- Frequent short trips: repeated short trips prevent the battery from being fully recharged by the car alternator, leading to a gradual power loss.
- Overcharging or a deeply discharged battery: excessive charging or allowing the battery to discharge completely can cause internal damage.
- Defective battery: manufacturing defects, though rare, can result in a new battery failing prematurely.
- Improper installation: an incorrect installation can cause electrical issues that drain the battery.
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Identifying and addressing these issues promptly can help restore the power unit’s performance and prevent further problems.
How to fix a car battery that doesn't hold a charge
| Issue | Fix |
|---|---|
| Corroded or loose terminals | Clean with a baking soda-water mix and wire brush or use a specialised terminal cleaner. Tighten loose terminals. |
| Faulty alternator | Test with a reliable multimeter (should read 13.8–14.2V while running). Replace if faulty. |
| Parasitic drain | Check for faulty lights, accessories, or wiring. Perform a parasitic draw test. |
| Battery deeply discharged | Use a slow charger to fully recharge before testing again. |
| Frequent short trips | Drive longer distances or use a battery maintainer if necessary. |
| Old or defective battery | If it won’t hold a charge after recharging, replace the battery. |
| Extreme temperatures | Park in a garage or use an insulated battery blanket in harsh weather. |
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