A dead car battery can derail your plans and leave you stranded. While calling roadside assistance is one option, there are also numerous tricks and tips you can try to revive your battery and get back on the road quickly. Understanding these dead battery remedies prepares you for a range of situations.
This guide covers 15 techniques for diagnosing battery issues, providing temporary power sources, recharging, and performing makeshift repairs when needed. With creativity and resourcefulness, a dead battery does not have to spell the end of your travels.
Table of Contents
- 1. Check the Battery Terminals and Connections
- 2. Try an Alternate Power Source
- 3. Jump Start from Another Vehicle
- 4. Use a Portable Jump Starter
- 5. Rock the Vehicle
- 6. Push Start the Vehicle
- 7. Check the Alternator Belt
- 8. Let the Battery Rest
- 9. Add Distilled Water
- 10. Charge the Battery
- 11. Use a Battery Maintainer
- 12. Apply a Load Tester
- 13. Check Warning Lights
- 14. Inspect the Battery Age
- 15. Make a Makeshift Repair
1. Check the Battery Terminals and Connections
Loose or corroded battery terminals are one of the most common reasons a car battery fails to start the engine. Simply cleaning and reconnecting the battery cables can get you up and running again.
Use a wire brush to remove any dirt, oxidation or white/green corrosion on the battery posts and cable clamps. Once cleaned to bare metal, secure the connections tightly to ensure full metal-to-metal contact.
Check that the retainers are holding the cables firmly to the terminals. Give the cables a light tug – they should not move. Loose connections can vibrate while driving and disconnect.
2. Try an Alternate Power Source
With the battery cables disconnected, you can attempt to start the car using an alternate 12-volt power source. This bypasses the dead battery to prove whether or not it is the root cause of failure.
Connect jumper cables from the positive and negative terminals of a portable jump starter pack, another vehicle’s battery, or a standard 12V battery charger to your car’s battery posts. Then try starting the engine – if it turns over, the issue is likely with your battery.
3. Jump Start from Another Vehicle
The classic method for starting a car with a dead battery is jump starting it using a live battery from another vehicle. The live car’s alternator recharges the dead battery enough to start the engine.
Park the live car hood-to-hood with the dead car, ensuring the vehicles do not touch. Connect the positive terminals, then negative terminals with jumper cables. Let the dead battery charge for 5-10 minutes before attempting to start.
Keep the engine of the live vehicle running during the jump start. Once the dead car is running, remove the cables in reverse order. Drive it for 30+ minutes to fully recharge the battery.
4. Use a Portable Jump Starter
For vehicles without a readily available donor car, keep a portable jump starter pack on hand. These compact devices contain an internal battery capable of providing hundreds of jump starts on a single charge.
First connect the clamps of the jump starter to your dead battery – positive first, then negative. Wait a few minutes, then start your vehicle normally. Disconnect the jump starter once the engine is running.
Portable jump starters are extremely convenient since another vehicle is not required. Just maintain the jump starter’s internal battery periodically by recharging it.
5. Rock the Vehicle
Rocking a manual transmission vehicle forward and backward can sometimes provide just enough juice from the battery to start it when other methods fail.
With the key in the “start” position, rapidly shift between first and reverse gears, rocking the vehicle back and forth without accelerating. The motion of the gears turning may start the engine.
This is less effective on automatic transmission vehicles, but shifting repeatedly between Drive and Reverse can provide motion to assist starting.
6. Push Start the Vehicle
Push starting uses the motion of the wheels spinning to jolt the engine to life when the battery itself cannot turn it over. This maneuver does require a second person to push the vehicle.
With the key turned to “start”, put the car into second gear (manual) or neutral (automatic) and push it to 3-5 mph. Once at speed, quickly engage the clutch (manual) or shift into drive (automatic).
The spinning wheels rotate the gears and crankshaft, which may start combustion. This may take a few attempts to get right.
7. Check the Alternator Belt
Before attempting to recharge or replace the dead battery, inspect the alternator belt. If the alternator belt has broken or slipped off, the battery cannot recharge from the running engine.
The belt should have no cracks or excessive wear, with tension that allows only 1/2 inch of deflection when pressed down. Adjust or replace loose/damaged belts to ensure proper charging ability.
8. Let the Battery Rest
Allowing a severely discharged or sulphated lead-acid battery to rest for 30-60 minutes can redistribute the electrolyte and improve starting capacity temporarily.
This rest period allows the battery plates to depolarize after heavy cranking draws down the charge. Just let it sit before trying again. Exercise restraint to avoid overcranking during attempts.
9. Add Distilled Water
One quick fix for a dead battery with low electrolyte is to top it off with distilled water. Low fluid exposes the plates to air and damages them. Do not use tap water.
Carefully pry off the vent caps and peer inside each cell. If the plates are not fully submerged, add just enough distilled water to cover them. Replace caps securely when finished.
10. Charge the Battery
Using a standard 12V battery charger is the most reliable method for restoring enough power to start a dead battery. But only do so if the battery is undamaged.
Connect the leads to the battery terminals – positive first, then negative. Select the appropriate amperage (10-15 amps) and allow the battery to charge fully. Do not leave it unattended.
Once charged, disconnect the leads and start the vehicle to verify normal function. Drive it immediately for 30+ minutes to prevent another dead battery.
11. Use a Battery Maintainer
To keep infrequently driven vehicles ready to start, connect a battery maintainer like a trickle charger or float charger. This slowly charges the battery to prevent discharge.
Hook up the maintainer leads to the terminals. The small continuous current will compensate for natural self-discharge without risk of overcharging.
Remove and properly store the maintainer if the vehicle will be unused for more than 2-3 weeks. Fully recharge the battery before driving.
12. Apply a Load Tester
Confirm a battery is truly dead and requires replacement by using a load tester to analyze its condition. This tool places a controlled high-draw electrical load on the battery.
If battery voltage rapidly drops below 9V under load, the battery is likely bad. Steady voltage around 10V indicates adequate strength. Replace batteries that fail under load.
13. Check Warning Lights
Review the instrument cluster when turning the ignition on (don’t start engine). If the battery warning light is illuminated, that signifies a charging issue.
The check engine light or reduced power warning may also appear with dead battery symptoms. Diagnose these problems before replacing the battery unnecessarily.
14. Inspect the Battery Age
Check the battery manufacture date on the label – older than 5 years significantly raises the chances of failure. Extensive heat exposure also shortens battery lifespan.
If faced with a dead battery of dubious age, err toward replacement. Attempting to recharge an excessively aged or damaged battery risks bursting/leakage.
15. Make a Makeshift Repair
If a battery terminal connector or cable is damaged, use household items for an improvised temporary repair. This can return function long enough to reach assistance.
Use a wadded aluminum foil ball or metal paperclip to connect a broken terminal to the post. Secure a split cable by wrapping with electrical tape.
These are short-term fixes only to get you back on the road. Properly repair all system damage once you are mobile again. Avoid driving far distances.
With a dead battery, trial and error with these tricks and tips is often required. You may need to use two or more methods in combination before hitting on the right solution.
First verify that the battery terminals are clean and tight, then attempt an alternate power source like a jump start. If unsuccessful, try adding water or rocking the vehicle between shifts. Patience and creativity helps overcome the setback of a dead battery. In a pinch, the resourcefulness of these techniques buys you just enough battery power to seek assistance. But for smooth travels, ensure your battery and charging system remain well-maintained.