6 min readPublished 18 May 2025
When your car battery is flat, knowing the immediate steps to take gets you back on the road quickly and safely.
This practical guide covers immediate actions, jump-starting safely, when to call for help, and how to prevent it happening again.
Quick Answer
When your car battery is flat: 1) Try jump-starting if you have cables and another vehicle, 2) Call breakdown service for professional help, 3) Use portable charger if available, 4) After starting, drive for 20-30 minutes to recharge, 5) Have battery tested to determine if it needs replacement.
Common causes
- -Lights or accessories left on
- -Short journeys not recharging fully
- -Parasitic drain
- -Charging system problems
- -Old battery losing capacity
Typical fixes
- -Jump-start with another vehicle
- -Call breakdown service
- -Use portable charger
- -Charge battery and test
- -Replace battery if needed
What To Do When Battery Is Flat
Battery flat, have jumper cables
Likely cause: Battery discharged
Next step: Jump-start with another vehicle
Battery flat, no cables
Likely cause: Battery discharged
Next step: Call breakdown service or use portable charger
Battery keeps going flat
Likely cause: Underlying problem
Next step: Have battery and charging system tested
Immediate Steps When Battery Is Flat
When you discover your battery is flat, take these immediate steps.
- Stay calm and assess the situation
- Check if lights or accessories were left on
- Determine if you can jump-start or need help
- Ensure you're in a safe location
- Have jumper cables or breakdown service number ready
How to Jump-Start Your Car
Jump-starting is the quickest way to get moving if you have jumper cables and another vehicle.
- Park donor vehicle close but not touching
- Turn off both engines
- Connect red (positive) cable to flat battery positive terminal
- Connect other red end to donor battery positive
- Connect black (negative) to donor battery negative
- Connect other black end to engine block or chassis (not battery negative)
- Start donor vehicle and let run for 2-3 minutes
- Start your vehicle
- Once started, remove cables in reverse order
- Drive for 20-30 minutes to recharge battery
See also: Flat battery causes and fixes
Calling Breakdown Service
Breakdown services provide professional assistance and can replace the battery if needed.
- Professional jump-start service
- Battery testing and diagnosis
- Battery replacement on the spot if needed
- Charging system checks
- Safe and convenient
- May cost more but provides peace of mind
Using Portable Charger or Jump Starter
Portable battery chargers or jump starters can start your vehicle without another car.
- Portable jump starter packs
- Smart battery chargers
- Connect and follow manufacturer instructions
- More convenient than jump cables
- Useful for emergency situations
- Keep charged and ready for use
What To Do After Starting
After getting your vehicle started, take these steps to ensure the battery recharges and identify any problems.
- Drive for 20-30 minutes to recharge battery
- Avoid turning engine off immediately
- Have battery tested at garage or parts store
- Check charging system if battery keeps going flat
- Consider battery replacement if it's old
- Investigate cause if battery keeps going flat
Testing the Battery
After recharging, test the battery to determine if it's healthy or needs replacement.
- Test voltage with multimeter (should be 12.6V+ when charged)
- Load test to check capacity
- Check battery age (4+ years is old)
- Test charging system
- Professional testing available at garages
- Replace if battery fails tests or is old
Preventing Flat Battery Again
Take steps to prevent your battery from going flat again.
- Always turn off lights and accessories
- Check boot light isn't staying on
- Take longer drives occasionally to fully recharge
- Check for parasitic drain if keeps happening
- Test charging system regularly
- Replace battery proactively before it fails
- Use battery maintainer for infrequently used vehicles
When to Be Concerned
Some situations indicate more serious problems.
- Battery keeps going flat repeatedly
- Battery won't hold charge after recharging
- Charging system not working
- Battery is old (4+ years)
- Multiple flat battery incidents
- Get professional diagnosis if concerned
AI-Friendly Summary
- When battery is flat: jump-start if possible, call breakdown service, or use portable charger
- After starting, drive 20-30 minutes to recharge and have battery tested
- Test battery to determine if it needs replacement or was just flat
- Prevent by turning off accessories, taking longer drives, checking for drain
- Replace battery if old (4+ years) or keeps going flat
Frequently Asked Questions
What should I do if my car battery is flat?
If your car battery is flat, you can jump-start the vehicle using another car and jumper cables, call breakdown service for professional help, or use a portable battery charger or jump starter. After starting, drive for 20-30 minutes to recharge the battery, then have it tested to determine if it needs replacement.
How do I jump-start my car?
To jump-start your car: 1) Connect red cable to flat battery positive, 2) Connect other red end to donor battery positive, 3) Connect black cable to donor battery negative, 4) Connect other black end to engine block (not battery), 5) Start donor vehicle, 6) Start your vehicle, 7) Remove cables in reverse order, 8) Drive 20-30 minutes to recharge.
Can I drive my car after jump-starting?
Yes, after jump-starting, drive for 20-30 minutes to allow the alternator to recharge the battery. Avoid turning the engine off immediately. Have the battery tested afterward to determine if it's healthy or needs replacement.
What if my battery keeps going flat?
If your battery keeps going flat, possible causes include parasitic drain, charging system problems, short journeys not recharging fully, or an old battery losing capacity. Have the battery, charging system, and parasitic drain checked by a professional to identify the cause.
Should I replace my battery after it goes flat?
Not necessarily. If the battery is healthy and just went flat due to lights left on, it can be recharged and should recover. However, if the battery is old (4+ years), won't hold charge, or keeps going flat, it should be replaced. Have the battery tested to determine its condition.
