My New Sealed Lead Acid Battery

This is my new sealed lead acid battery. Difference from conventional flooded lead acid battery is that the electrolyte is in gel form instead of the liquid form in the former. Advantage is that while kept indoors, it is less likely to give out acid fumes. Disadvantage is that the projected battery life is lesser for this sealed lead acid battery. These batteries are also known as SMF or sealed maintenance free batteries because usually there is no need to check and top up the levels of battery water. Another name is VRLA or valve regulated lead acid battery because a valve regulates the venting of gases produced. But the gas production is much lesser in SMF compared to flooded lead acid batteries. Nuts and bolts for fixing the terminals and the caps for the terminals are seen here.

The terminals can be seen well now after removing the caps. Two nylon wires have been attached to either side so that two people can lift it up when needed by holding on two sides.

For a curiosity, I checked the weight of this 100AH battery. It is quite heavy and weighs 32.3kg and hence not easy to handle without the help of another person! The precaution for disposal has been indicated as it contains lead.

This is how the output wires have to be connected so that the terminal caps can be used to cover them.

Now the terminal caps have been placed over the connection. As can be presumed from the red colour of the wire, this is the positive terminal.

This label is quite important as it shows the recharge voltages. The battery has to be charged in CC-CV mode only. CC-CV mode means constant current/constant voltage mode. In the initial phase, the charger gives a constant current to the battery for rapid charging until the battery voltage approaches a maximum safe level. During this period, the internal voltage of the battery rises. When a preset voltage is reached, the charge control integrated circuit switches the system to constant voltage mode. Charging stops when the preset termination voltage of the battery is reached.

Maximum charging current is given as 30A and minimum charging current as 10A. Different voltage settings have been given for float and cyclic operations. Float operation is as in an uninterruptible power supply (UPS) where full charge standby is needed. In such case the recommended charging voltage is 13.7V +/- 0.1V. Cyclic operation is as in portable ham radio operations where you take the fully charged battery to the field and recharge while back home. So the battery will be nearly empty at the time of recharging. In cyclic operation, 14.7V +/- 0.1V is the recommended charging voltage. This is for 20-30 degrees Centigrade ambient temperature. Temperature compensation is needed with reference voltage taken as 25 degrees Centigrade. In float mode it is -18mV/deg C, and in cyclic mode it is -30mV/deg C. These values are for a single 12V battery unit. Such precautions are more important in case of sealed lead acid batteries than flooded lead acid batteries.