Mipro 12V Rechargeable Battery Sealed Lead-Acid Battery For MA707/708/808

Mipro offers sealed 12 V, 4.5 AH lead-acid rechargeable batteries for it’s wireless Public Address (PA) systems such as the MA-707, MA-708 and MA-808. These PA systems require two rechargeable batteries so it is recommended that you replace both of them simultaneously.

About Sealed Lead-Acid Batteries

In the mid 1970s, scientists industrialised a maintenance-free, lead-acid battery that can function in any position. The liquid electrolyte is gelled into dampened separators and the enclosure is sealed. Safety valves allow venting during atmospheric pressure changes, charge and discharge. Motivated by diverse market needs, two lead-acid systems emerged.

• The small Sealed Lead-Acid (SLA), also known under the brand name of Gelcell.
• And the bigger Valve-Regulated-Lead-Acid (VRLA).

Both batteries are comparable.

Your engineering friends may remind you that the word ‘Sealed Lead-Acid’ is a contradiction because no rechargeable battery can be completely sealed. Distinct from the Flooded Lead-Acid Battery, both SLA and VRLA are intended with a Low Over-Voltage potential to forbid the battery from attaining its gas-generating potential during charge since excess charging would cause water depletion and gassing. Therefore, these batteries can never be charged to their complete potential. To decrease dry-out, sealed lead-acid batteries use lead-calcium instead of the lead-antimony.

Some Interesting Facts About Sealed Lead-Acid Batteries

• The ideal operating temperature for the Lead-Acid Battery is 25*C (77*F)
• Raised temperature decreases longevity
• As a guideline, each 8°C (15°F) increase in temperature cuts the battery life in half
• A VRLA, which would last for ten years at 25°C (77°F), would only be good for five years if operated at 33°C (92°F)
• The equivalent battery would desist after two and a half years if kept at a continuous desert temperature of 41°C (106°F)

Source: Battery University.