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Lead acid battery charging TIPs
pa0nhc 20160323

In scoot mobiles, fully closed, glass fleece, deep cycle batteries are used (AGM). A good charger and low operating temperatures make a battery lifespan of up to 10 years possible. When the battery is fully charged, modern chargers automatically reduce the charging current to such a low level, that only the battery self-discharging current is compensated. Overcharging and battery damage is impossible. In AGM batteries a small amount of gassing is regenerated without damage.

Some scoot mobile vendors state that, when the battery is charged, a charger may must be disconnected when the battery is fully charged.

That is non-sense.

In my opinion, when not in use, the lifespan of AGM batteries is made LONGER, if leaving them connected to a good charger.

Battery Maximizer user manual

" The Battery Maximizer Mobility Charger is a safe, fully automatic, efficient, multi-stage full switching charger. It is designed to properly charge VRLA / SLA / AGM / Gel lead-acid batteries without having to worry about overcharging. "

Denoising a scoot-mobile-charger

   Charging process:
In the above mentioned charger (and most modern chargers) a microprocessor regulates a "multi-stage" charging process :
- Fast charging begins with current limiting. For this charger 5A.
- As soon as the battery voltage reaches 29.4 V (=2.45V/cell), voltage limiting starts, and the charging current decreases slowly.
- As soon as the charging current is reduced to f.i. 0,02 C, the charging voltage is lowered to 27.6 V (2.30V/cell).
- The charge current decreases immediately strongly.

The charging-end-voltage now is 2.3V/cell, preventing to much gas generation, and therefore overcharging is impossible.

    Unequal cell voltages.
A 24V lead acid battery contains 12 cells. Small differences in cell voltages can appear.
In my opinion, a cell with a bit less charge (lower voltage) can be slowly topped up by leaving the charger on. In time, small differences in cell voltages will be canceled out. Preventing one cell is earlier deep discharged than the others, and will be damaged.

REM: A little gassing in AGM cells is regenerated to water and acid. The cells are fully closed and not leaking.

    Frost damage.
All fully charged lead-acid-battery contains sulfuric acid with a density of 1,28. According to battery manufacturers such a battery can withstand 25C frost !

A fully discharged battery contains no sulfuric acid, but only water. Below 0C it freezes and will be damaged.

So keep charging.