SunXtender Technical Manual
Table Of Contents
Document No. 6-0100 Rev. H   
Page 28 of 43 
APPENDIX A – GLOSSARY OF BATTERY TERMS 
AGM - 
Stands for Absorbed Glass Mat. This is the separator system used 
in all Sun Xtender® AGM batteries. 
Active Material - 
Electrode material which produces electricity during its chemical 
conversion. In the positive plate it is lead dioxide. In the negative 
plate, it is sponge lead. 
Ampere - 
Unit of electrical current abbreviated as amps or A.  
Amps = Watts/Volts or A = W/V. 
Ampere Hour (Ah) - 
The capacity of a storage battery is measured in ampere hours. 
One ampere hour is defined as a current flow of one ampere for a 
period of one hour. Five ampere hours means a current flow of 
one ampere for five hours, a current flow of 2.5 amperes for 2 
hours, or any multiple of current and time that will result in five. 
This relationship can be expressed as follows:  
Capacity (Ampere hours) = I*T, where I is the current (in 
amperes) and T is the time (in hours). The capacity of a storage 
battery is based on a given discharge rate, since the capacity will 
vary with the rate of discharge.  
Battery - 
Two or more chemical cells electrically connected together to 
produce electric energy. Common usage permits this designation 
to be applied also to a single cell used independently. 
Boost Charge - 
A charge applied to a battery which is already near a state of full 
charge, usually of short duration. 
C/X Rate - 
Discharge rate in amperes that will take X hours to fully discharge 
the battery. C/1 = 1-hour rate, C/120 = 120-hour rate, C/0.5 = 
½-hour rate (normally written as 2C). 
Capacity - 
The quantity of electricity delivered by a battery under specified 
conditions, usually expressed in ampere hours. 
Capacity, Rated - 
A designation by the battery manufacturer which defines the 
performance of a new battery at a defined rate of discharge. For 
Sun Xtender® AGM batteries, the rated capacity is based on the 
24 hour rate.  
Capacity, Residual - 
Capacity remaining at a particular point in time and operating 
conditions, usually at a partial state of charge condition. 
Case - 
The battery box which contains the cells and associated internal 
connectors.  
Cell - 
An electrochemical device composed of positive and negative 
plates, separator, and electrolyte which is capable of storing 
electrical energy. When encased in a container and fitted with 
terminals, it is the basic building block of the battery. 
Cell Reversal - 
Reversing of polarity within a cell in a multi cell battery due to 
over discharge. 
Charge - 
The conversion of electrical energy from an external source, into 
chemical energy within a cell or battery. 
Charge Rate - 
The rate at which current is applied to a cell or battery to restore 
its capacity. 
Charge Retention - 
The ability of a charged cell or battery to resist self discharge. 
Charge, State of - 
Ratio of the amount of capacity remaining in a battery to the 
capacity when fully charged. A battery at 25% state of charge 
has 25% capacity remaining versus what it could give if fully 
charged.  
Charger - 
Device capable of supplying electrical energy to charge a battery. 
Charging - 
The process of converting electrical energy to stored chemical 
energy. The opposite of discharging. 










