Sealed maintenance-free battery look different from other battery types. They are more compact because there is no free electrolyte (which is used in the form of a gel, filling the cavities of the plate) making them more "volume efficient" and taking up less space for their energy storage capacity. Because they are filled with electrolytes only once during activation, there is no filling cap. Instead, a sealing plug permanently covers the filling port. Also, there is no exhaust pipe in this battery.

The structure of this cell causes the gases released inside to recombine inside the cell, so there is no need for an exhaust pipe. SMF cells can be sealed because inside the cell, the negative plate is never fully charged, so no hydrogen gas is produced. The positive plate produces oxygen during discharge, but instead of venting the oxygen out of the exhaust, it reacts with the charged active material on the plate to become water until the battery charges and converts the water to acid. This process is called recombination technology, and this design makes our batteries unique.

Sealed batteries require a higher capacity than dry-charged or conventional types. Make sure you never charge this battery type with a traditional battery charger. You should choose a professional quality charger.

Sealed types of batteries are pre-activated at the factory, which means that electrolyte has been added to the battery and the casing is sealed. Here are some instructions to follow:

Connect the cables to the battery terminals before turning on the charger, the red cable to the positive (+) terminal and the black to the negative (-) terminal

Gel battery or SMF battery must not be charged above 14.4V as it will damage the battery

Choose a low amperage initially when charging, or see the instructions that came with the battery to charge at a specific amperage

Load the test battery for 15 seconds at 3 times the amp hour rating or use an automatic battery tester to determine battery condition, then check the voltage

12V battery should be at least 12.4V

Then you can install the battery

If the voltage reading is below 12.4V or the battery fails the automatic battery test, repeat the charge and test cycle

Changshu Wanlong Power Technology R&D Co., Ltd. is a lead acid battery manufacturer from China. The company sells 12v deep cycle gel batteries all year round.