How Do I Revive a Dead Battery?

The Battery Life Saver electronic device can be used to revive a dead battery that has accumulated too much sulfate build up or has been allowed to sit unused for a long period of time.

However, it will not work on a battery that has a shorted or open cell. See the “How to Test for a Short or Open Cell” page for details on shorted cells and how to tell if your battery has them.

This procedure works for a car-auto, deep cycle, marine and all other lead acid battery applications. It will also work with AGM and GEL batteries.

  1. A dead battery is one that will not hold a charge, and in some cases, they are unable to take a charge.
  2. It can take several days to a couple weeks to revive a dead battery, depending on how bad the battery is, the size, and how often you cycle(charge and discharge) the battery with BLS attached.
  3. For a 12 volt battery, you will need the BLS-12/24-B and a good automotive battery charger, preferably with a rating of 6 to 10 amps. For batteries that cannot take a charge, it is best to use an old fashioned battery charger, not one of the newer high tech Smart Battery Chargers. The newer smart battery chargers will not turn on if the voltage of the battery is too low. This does not mean that the battery is completely dead, just that the charger will not turn on. If you do not have a manual charger available, you can jump start the bad battery(just like jump-starting your car battery) to get the battery voltage high enough for the smart charger to turn on (contact us for more information on this procedure).
  4. The key to this procedure is to cycle (charge and discharge) the battery with the BLS attached. The BLS gradually dissolves the sulfate crystals with every cycle. To Battery Life Saver works from the power of the battery. You can either let the BLS discharge your battery or add some type of load(i.e. a light) to help discharge the battery.
  5. Step 1: Connect both the BLS and the charger to the battery, paying attention to the polarity.
  6. Step 2: Charge the battery with the BLS attached until the voltage is at least 12 volts or completely charged.
  7. Step 3: Leave the Battery Life Saver connected to the battery without the battery charger for a
    period of time(if it is a single 12 volt battery, 20 hours should be enough time to discharge with the BLS). DO NOT LET THE VOLTAGE GO BELOW 10.5 VOLTS. It is best to stay above 12.2 volts on a 12 volt battery.
  8. Step 4: When the battery voltage is between 12.2 and 12.5 repeat step
    2 and 3.
  9. Work back and forth between 2 and 3 until the battery comes back up to operational condition. If you cycle(charge and discharge) the battery every day with the BLS connected, the battery should come back sometime between 3 days and 2 weeks.
  10. See “Testing a Battery and the BLS” for details on how to determine if the battery is in usable condition.

"I am an RV owner. I want to tell you that the Battery Life Saver brought back my $225 battery that was in very bad shape. It took a while but it’s still working great. It makes me very happy."

T.B. Bend

BLS Customer