Rich electric Invertek SuperCombi SC-1500-12X, User Manual

Page: 37 / 155

Rich Electric Co. “SuperCombi” User Manual V7.19 Copyright 2009
Page 37
Chapter 3 Battery Types
CAUTION: Never attempt to charge a primary (non-rechargeable) battery.
All charging voltages noted below will be for 12V batteries at 25°C.
3.1 Sealed Batteries
The general class of sealed batteries suitable for solar inverter systems are called VRLA
(Valve Regulated Lead-Acid) batteries. The two main characteristics of VRLA batteries are
electrolyte immobilization and oxygen recombination. As the battery recharges, gassing is limited
and is recombined to minimize the loss of water.
The two types of VRLA batteries most often used in solar are AGM and Gel.
3.2 AGM:
Absorbed Glass Mat batteries are still considered to be a “wet cell” because the electrolyte is retained
in fiberglass mats between the plates. Some newer AGM battery designs recommend constant
voltage charging to 2.45 volts/cell (14.7V). For cycling applications, charging to 14.4V or 14.5V is
often recommended. Typical float voltage of 13.5~13.8v
AGM batteries are commonly replacing the older style flooded (Wet) type battery. AGM batteries
are designed for different applications can vary depending on their type. These can be suited to high
or low discharge applications with good daily cycling life. Some manufactures offer over 1000+
cycles to 100% discharge and with service life of up to 14 years. These batteries should not be
equalized unless stated from the battery manufacture. Since gassing could be vented causing the
battery to dry out.
There is also a potential for thermal runaway if the battery gets too hot, and this will destroy the
battery. AGM batteries are affected by heat, and can lose 50% of their service life for every 8°C
(15°F) over 25°C (77°F).
It is very important not to exceed the gas recombination capabilities of the
AGM. The optimum charging temperature range is from 5 to 35°C (40 to 95°F).