The second stage of three-stage battery charging. Voltage remains constant and current tapers as internal battery resistance increases during charging. This ensures complete charging.
Amp Hour Capacity
The ability of a fully charged battery to deliver a specified quantity of electricity (Amp-Hr., Ah) at a given rate (Amp, A) over a definite period of time (Hr.). The capacity of a battery depends upon a number of factors such as: active material, weight, density, adhesion to grid, number, design and dimensions of plates, plate spacing design of separators, specific gravity and quantity of available electrolyte, grid alloys, final limiting voltage, discharge rate, temperature, internal and external resistance, age and life of the battery (or battery bank).
AGM (Absorbed Glass Mat)
A lead acid, maintenance-free battery.
AWG (American Wire Gauge)
A standard used to measure the size of wire.
A device that is used to replenish the capacity of a battery (its “charge”) by supplying DC current to the battery.
The first stage of three-stage battery charging. Current is sent to batteries at the maximum rate they will accept while voltage rises to full charge level.
In a battery, one discharge plus one recharge equals one cycle.
A deep cycle occurs when a battery is discharged to 50% of its capacity (50% depth of discharge). A deep-cycle battery is one that is intended to be deeply discharged and charged repeatedly.
Depth of Discharge (DOD)
The amount of energy or charge removed from the battery bank, usually expressed as a percentage. A depth of discharge of 0% indicates a fully-charged battery, and a depth of discharge of 100% indicates a fully-discharged battery.
Stored energy being released from a battery.
These loads are those that run off a DC electrical system (battery). A few examples of DC loads are pumps, lights, fans, power vents, toilet, inverters, and some water heaters. DC loads rely on the batteries for power.
Auxiliary charger that can charge your engine battery when the main charger is in
Bulk or Absorption mode and the house battery voltage is at 13.2 volts DC or higher.
A battery that is separate from the House battery, specifically designated to provide power for engine starting. In a system with a house battery and an engine battery, the inverter would not have its main power cables connected to the engine battery.
Equalization or Equalize Charge
A deliberate, controlled overcharge of the batteries which brings all cells up to the same voltage potential, reduces sulfation and stratification in flooded (or wet) lead-acid batteries. Not necessary and harmful on Gel or sealed batteries.
The third stage of three-stage battery charging. After batteries reach full charge, the charging voltage is reduced to a lower level to reduce gassing (boiling of electrolyte) and prolong battery life. This is often referred to as a maintenance charge, since rather than charging a battery it keeps an already-charged battery from self-discharging.
A type of battery that uses a gelled electrolyte solution. These batteries are sealed and are virtually maintenance free. Not all sealed batteries are the gel cell type.
Ground Fault Circuit Interrupter (GFCI)
A protective device that rapidly de-energizes a circuit when current to ground exceeds a predetermined value.
Ground Fault Protection (GFP)
A circuit protection device that prevents the flow of electrical current to earth if a short circuit is present. Usually required in wet locations — for example, for outdoor, kitchen, and bathroom circuits.
A control circuit that disconnects charge current flowing to batteries when voltage reaches a dangerously high threshold. Prevents damage created by excess gassing (or boiling) of electrolyte.
The house battery is the large capacity, deep cycle battery that is connected to the inverter/charger’s main DC terminals.
These are systems that combine two or more renewable energy technologies. A combination photovoltaic and wind system, or a photovoltaic system that recovers and utilizes heat from the panels for space or water heating are hybrid system examples.
Idle Current The amount of electrical power required to keep an inverter ready to produce electricity on demand.
TVs, VCRs, stereos, computers, and electric motors (power tools, vacuum cleaners, for example) are examples of inductive loads which surge on start up. They require a high start-up current compared to a resistive load such as a toaster or a coffee pot.
The peak power that a load will draw at the instant that it starts up.
A device that converts DC power to AC power.
Light Emitting Diode (LED)
A device used to display various status functions.
A voltage drop caused by resistance in wire during transmission of electrical power over distance. Line loss is why you must increase the size of DC battery cables the further the inverter is from the battery or battery banks.
A control circuit that stops the flow of electricity from batteries to loads when battery voltage drops to low levels. This prevents over-discharge of the batteries.
Main Charger The main charger output is at the main DC terminals on the inverter/charger and connects to the house batteries. The main charger replenishes the charge to the house batteries. The main charger can be configured as a two stage or a three-stage charger.
Maximum Power Point Tracking (MPPT)
Every PV (solar electric) device has a point where maximum current is delivered. MPPT electronically adjusts the output of a PV device to the maximum power point.
Modified Sine Wave (MSW)
An AC wave form (generated by many inverters) that is a pulse width modified square wave.
National Electric Code (NEC) The electrical wiring and installation standards used in the
Designating or pertaining to electrical potential. The negative terminal is the point from which electrons flow during discharge.
An electrical system that is not connected to a utility distribution grid.
A control circuit designed to protect an inverter or similar device from loads exceeding its output capacity. (A fuse, for example, is an overcurrent protection device.) All Xantrex inverters have internal circuitry to protect themselves from most overload/overcurrent conditions.
Photovoltaic (PV) Panels
These are the devices that convert sunlight into electricity.
Photovoltaic (PV) System
The components that form a solar electric generating system, usually consisting of PV modules, charge controller, circuit protectors (fuses or breakers) and batteries.
Power factor is the ratio between true power (
The feature of the charger to reduce its output when the AC power being consumed by the charger and external AC loads connected to the output of the inverter are in excess of the input breaker rating.
Toasters, coffee pots, and incandescent lights are examples of resistive loads. They use a resistive heater element to generate heat or light.
The optimal output wave form of alternating current (AC). A smooth wave going above and below zero.
Switched Mode Power Supply (SMPS)
Most IT equipment is connected to the mains supply via a built-in Switched Mode Power Supply (SMPS).
The SMPS is used to convert the incoming alternating current (AC) into the various levels of direct current (DC);
the direct current is required to supply power to the various internal circuits and components such as: motherboards,
drives, communications or USB devices.
Switch mode power supplies are designed to work from a clean, stabilised and regulated sinewave supply.
This is a perfect mains scenario with no sags, surges, transients and spikes, electrical noise and brownouts.
Whilst the occurrence of some of these in the mains supply at low magnitude and duration may not present the
switch mode power supply with operational problems they can cause component degradation and reduce overall reliability.
Off course any break in the supply can lead to a complete crash.
As a battery discharges, its plates become covered with lead sulfate. With regular recharging, the lead sulfate leaves the plates and recombines with the electrolyte. If the lead sulfate remains on the plates for an extended period of time (over two months), it hardens, and recharging does not remove it. Sulfation reduces the effective plate area and the battery’s capacity. Equalization of flooded (or wet) batteries helps to reduce sulfation.
The amount of current an inverter can deliver for short periods of time. Most electric motors draw up to three times their rated current when starting. An inverter will “surge” to meet these motor-starting requirements.
Optimal battery charging voltage is dependent on the battery temperature. As the ambient temperature falls, the proper voltage for each charge stage needs to be increased. When the ambient temperature increases, the proper voltage for each charge stage needs to be decreased. On some products, the Battery Temperature Sensor (BTS) allows the charger or inverter/charger to automatically scale charge-voltage settings to compensate for ambient temperatures. On others, there is a setting for hot, cold, and warm settings.
TSC (Temperature Sensitive Charging)
The ability of the charger to adjust its charging voltage based on the temperature sensed at the battery bank if a temperature probe is used.
A measure of the “apparent” power equivalent to the true power (watts) in resistive loads, but exceeding watts in non-resistive loads. VA is calculated by multiplying volts times amps without using power factor.
A type of battery that uses liquid as an electrolyte. The wet cell battery requires periodic maintenance: cleaning the connections, checking the electrolyte level and performing an equalization cycle.
Wind Energy Conversion System
Usually known as a windmill or a wind turbine. WECS convert energy from the wind into electricity. A complete set of components may include the following components: Wind Turbine, wiring, inverter, controller, batteries and other components depending upon the sophistication of the system.
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