SunXtender Technical Manual

Document No. 6-0100 Rev. G
Page 10 of 43
CHAPTER 3 - TECHNOLOGY COMPARISON
3.1 Sun Xtender® versus Flooded Batteries
Flooded-electrolyte lead acid batteries have been around since 1859 and tend to be less
expensive than AGM or Gel batteries. However, they have major deficiencies compared to
AGM or Gel batteries. For instance, deep cycle flooded lead acid batteries contain antimony in
the grid alloy which causes a high rate of self discharge and rapid water loss due to gassing
reactions. The escape of hydrogen and oxygen from the battery represents a serious safety
hazard if the gasses are not ventilated properly. In flooded batteries, replacing the antimony
lead alloy with calcium lead alloy reduces the amount of gassing and water loss, but the cycle
life is much lower and they are no longer considered deep cycle batteries.
Electrolyte stratification can occur in all types of flooded batteries. As the battery is discharged
and charged, the concentration of acid becomes higher at the bottom of the cell and becomes
lower at the top of the cell. The low acid concentration reduces capacity at the top of the plates,
and the high acid concentration accelerates corrosion at the bottom of the plates and shortens
the battery life. Although stratification can be minimized by raising the charging voltage so that
the increased gassing agitates the electrolyte, this will accelerate the water loss and watering
frequency.
One other difference is that flooded batteries cannot tolerate freezing temperatures when in the
discharged state, whereas AGM batteries are resistant to damage by freezing temperatures.
The following table provides a side by side comparison of Sun Xtender® AGM and flooded deep
cycle batteries.
Table 3-1. Comparison of Sun Xtender® AGM Batteries with Flooded Deep Cycle Batteries
Characteristic
Sun Xtender® AGM Battery
Flooded Deep Cycle Battery
Self-discharge at room
temperature
1 to 3% per month – remains
stable over life.
5-10% per month when new –
increases drastically with age
due to antimony contamination of
the negative plate.
Water addition
Never.
Frequent – increases
dramatically with age due to
antimony contamination of the
negative plate.
Hydrogen gas emissions
Generally negligible unless
severely overcharged.
Significant volume is generated
and must be ventilated to prevent
explosion.
Electrolyte spillage during
storage, shipping and handling
Non-spillable - Electrolyte is
retained in AGM separator.
Electrolyte spills when battery is
tilted, inverted, or cracked.
Electrolyte stratification during
operation
No stratification occurs.
Stratification occurs when
operated at low charging
voltages or in taller batteries.
Tolerance to freezing
temperatures
Resistant to damage when
frozen.
Battery destroyed when frozen.