It depends. Batteries can appear dead for a few different reasons. Attempting to charge a truly dead battery likely won’t help revive it. But if the battery still has some life left, charging may bring it back to working order. Let’s take a closer look at why batteries die and when charging can potentially revive them.
Why do batteries die?
Batteries provide power by converting chemical energy into electrical energy. This process relies on chemical reactions within the battery. Over time and through use, the materials inside the battery can undergo changes that reduce its ability to produce electricity.
The most common reasons batteries lose their ability to hold a charge include:
- Physical damage – Cracks and leaks let chemicals escape.
- Dendrites – Tiny metallic spikes that develop and short-circuit the battery.
- Sulfation – Lead sulfate crystals build up on the battery plates.
- Corrosion – Rust and oxidation degrade connectors and plates.
- Loss of electrolyte – The fluid inside dries up over time.
Once a battery experiences enough internal damage or material breakdown, it can no longer generate electricity and is considered dead or beyond repair. Attempting to recharge a dead battery, at best, will provide only a brief burst of energy before failing again.
When can a dead battery be revived?
While a truly dead battery cannot be revived, one that still retains some capacity can sometimes be nursed back to full life. Here are some instances when recharging a very weak or unresponsive battery may be successful:
- Low charge state – The battery still has juice but has discharged below the cut-off voltage needed to power the device. Recharging restores it to an operational voltage level.
- Sulfation buildup – Soft lead sulfate crystals have developed but not hardened into permanent plaques. Recharging can dissolve the sulfates and reactivate the battery.
- Electron imbalance – Continued deep discharging has imbalanced the electrons between plates. Reconditioning may redistribute them.
- Cold temperature – Exposure to extreme cold slows the battery’s power delivery. Warming and recharging improves battery function.
The key is that the battery must retain enough active material and structural integrity to accept and hold a charge. If the damage is not too severe, charging can often bring a battery back from the brink of failure. Let’s look at how to go about reviving a dead battery.
How to revive a dead battery
If your battery shows any signs of life, try these steps to recondition it and potentially bring it back from the dead:
- Check voltage – Use a voltmeter to check battery voltage. Any reading above 2 volts means revival may be possible.
- Gently recharge – Use a low amperage charger or variable charger set to a low amperage to slowly add power over several hours. This helps redistribute electrolyte and electrons within the battery.
- Test and recharge again – Check the voltage after initial charging. If it continues to climb, keep charging in short bursts until voltage stops increasing.
- Load test – Connect a small load like a flashlight bulb and verify the battery can deliver power. If so, it may work for lower demand uses.
- Consider replacements – If the battery holds only a fraction of original capacity, replace it or relegate it to low drain uses.
Charging too rapidly, over-charging, or charging without proper cautions can lead to more battery damage. Patience and monitoring voltage and temperature changes are key to successfully reviving weak batteries.
Battery revival tips
To maximize your chances of bringing a battery back to life, keep these tips in mind:
- Check open circuit voltage first – No reading means the battery is likely too far gone.
- Choose an appropriate charger – Use one designed for the battery type and voltage to avoid damage.
- Charge slowly – Low and steady current helps redistribute chemicals and electrons.
- Avoid heat buildup – Stop charging if battery becomes hot to touch.
- Consider desulfation – Specialized chargers may help dissolve sulfates and extend battery life.
- Be patient – It may take several charging sessions over hours or days to see improvement.
- Don’t overcharge – Stop charging once voltage hits maximum level.
- Check capacity – Compare revived capacity to original rating to determine if replacement is needed.
With time and care, these steps can successfully bring some left-for-dead batteries back to working order. But the battery must retain enough internal structure to accept and retain the applied charge.
When to avoid charging a dead battery
While charging can revive some batteries, it will fail or potentially cause damage if the battery is too far gone. Avoid attempting to charge a battery that exhibits these traits:
- No voltage – Zero volts indicates no power remains and likely severe internal damage.
- bulging or leaks – Physical damage prevents safe charging as chemicals can escape.
- Severely corroded – Heavily oxidized plates and connectors cannot deliver or receive charge.
- Frozen electrolyte – Charging a frozen battery can cause leaks or rupture.
- Previous overheating – Prior overcharge damage means it cannot accept additional charging.
Batteries displaying these conditions require replacement rather than charging. Attempting to revive batteries in this state poses a fire or safety risk.
When to replace a battery
If a dead battery does not respond to recharging, or only delivers a fraction of its original capacity, replacement is the best option. Here are signs it’s time to retire rather than revive a battery:
- Less than half original capacity
- Won’t hold charge for more than a day
- Frequently needs recharging under normal use
- Excessively long charge times
- Over 3 years old
- Bulging, leaks, or deformities
- Corroded terminals
When a battery exhibits multiple degraded performance traits, it’s near the end of its service life. The effort to repeatedly recharge often outweighs the cost of a quality replacement. Investing in a new battery saves time and frustration down the road.
Conclusion
Reviving a dead battery is sometimes possible but not guaranteed. The key is acting while the battery still retains some capacity and functionality. With gentle charging, patience, and monitoring voltage changes, a battery on the edge of failure can often be coaxed back to life. But if a battery is too far gone or shows evidence of serious physical or chemical damage, replacement rather than revival is the wise choice.
