How to Fix a Dead SLA Battery

Sealed Lead-Acid, or SLA, batteries are mainly used in cars, motorcycles and trucks. These batteries are considered maintenance-free, as you cannot top-up the fluid levels in the individual cells. While it is technically possible to access the cells, it's not advisable. Tampering voids your warranty and, as the cells contain sulphuric acid, is potentially dangerous. The best way to attempt to fix your dead SLA battery is to allow it to charge at a very low rate in excess of 24 hours.

• 1

  Put on protective gloves. Disconnect the negative cable from your dead SLA battery using a wrench. Disconnect the positive cable from your battery using a wrench.

• 2

  Remove the dead SLA battery from your car and place it on a battery tray on a stable work surface near to where your battery charger is located. You want your dead SLA battery to be totally disconnected from everything if you're going to fix it.

• 3

  Set your battery charger to its lowest setting (often called trickle charge). You want the output amps from the charger to be the lowest possible. One or two amperes is fine. Ensure your battery charger is set for the voltage that matches your SLA battery. Most car batteries are 12-volts. The voltage is on the label located on the top or side of your SLA battery.

• 4

  Attach the clamp on the end of the red wire extending from your battery charger to the positive terminal of your SLA battery. This is marked "+." Attach the clamp on the end of the black wire to the negative ("-" ) terminal of your SLA battery.

• 5

  Plug your charger into the electrical socket. Turn on your charger. Check that it's charging the battery at the correct amperes and voltage.

• 6

  Leave your battery charging for at least 24 hours. Turn off your charger and unplug it. Remove the two clamps attached to your SLA battery.

• 7

  Replace the SLA battery in your car. Reconnect the positive and then the negative cables to the corresponding battery terminals using a wrench. Don't attempt to use the battery for a day or two. You need to see if the SLA battery retains its charge.

• 8

  Start your car engine. If the engine turns over quickly and fires-up, your SLA battery is fixed.