Inverter Battery Issue, having trouble with batteries discharging rapidly

Power Inverter Working Principle

Inverters, in their most basic form, operate similar to battery chargers in reverse: they take 12vDC power from a battery and run it through modern circuitry to change it into 120vAC current.

Whether your power inverter needs to be wired to your car battery depends on the model of the inverter and what you intend to run with it. For electrical loads up to 200 watts, the power-inverter can be plugged into the car’s cigarette lighter. This allows you to power laptop computers, small power tools, most small appliances, and even a small (13") TV directly through the cigarette lighter. If you want to power larger equipment, or if you want to run more than one item at a time, a direct connection to your car battery is necessary. Generally, if you intend to power loads of more than 200 watts, your inverter should be direct-wired to the battery to ensure safe operation.

To find how long your battery’s charge will last with any given inverter, use this formula:

Take the wattage being used (400W) divided by the battery voltage (12 Volts) to see how many amps are being drawn from the inverter: 400 Watts/12 Volts = 33.33 Amps.  Inverters only convert power at around 90% efficiency, so that means the inverter is really drawing around 37 amps (33.33 Amps / .90 = 37 Amps).  A typical car battery has a reserve capacity of about 80 minutes (80 minutes @ 25 Amps). So if you are drawing 37 Amps with the 400W inverter it will completely discharge the battery in 54 minutes ((80 minutes * 25 Amps) / 37 amps = 54 minutes).

A few types of alarms and their causes:

Low or no output voltage from the inverter

1. Poor contact at terminals. Unhook and re-hook the 12-volt connections, and try again.
2. Using incorrect type of voltmeter to test output voltage. Use a true RMS reading meter.

Blowing up of inverter fuse

Your power inverter is fitted with 25-amp spade type fuses, which should not have to be replaced under normal operating circumstances. A blown fuse is usually caused by reverse polarity or a short circuit within the appliance or equipment being operated.

If the fuse does blow:

   1. Disconnect the appliance or equipment immediately.
   2. Find the source of the problem, and repair it.
   3. Install the new fuse (supplied with your power inverter.)

Please do not install a fuse higher than 25-amps, as this may damage the inverter. Make sure to correct the cause of the blown fuse before using the inverter again.

The low battery alarm is constantly on

1. The input voltage is below 11 volts. Recharge or replace battery to maintain adequate power input.
2. Poor or weak battery condition. Recharge or replace battery.
3. Inadequate power being delivered to the inverter or excessive voltage drop. Check the condition of your cigarette lighter socket. Clean or replace if necessary.

How To Connect your Inverter
Make sure the ON/OFF rocker switch is in the OFF (0) position. (If connecting in a vehicle, remove the cigarette lighter from its outlet.)  Push the 12-volt power plug firmly into the outlet.  Switch the inverter rocker switch to the ON (I) position. The LED indicator light should glow GREEN verifying the inverter is receiving power.  Turn the inverter rocker switch to the OFF (0) position. (The GREEN LED power indicator light may flash briefly and/or the internal speaker may make a brief "beep." This is normal).  Make sure that the appliance to be operated is turned OFF. Plug the appliance into one of the two AC outlets.  Turn the inverter rocker switch to the ON (I) position.  Turn the appliance on.

The LED Indicator briefly flashing when you first turn the inverter ON, is a sign if that there is a short circuit within the power supply.  Turn the inverter OFF.  Remove the 12-volt plug from the cigarette lighter socket.  Firmly re-insert the plug.  Turn the inverter ON again.  If this does not remedy the problem try using a different 12-volt power source.

Using the Inverter to Operate a TV or Audio Appliance
The inverter is shielded and filtered to minimize signal interference. Despite this, some interference may occur with your television picture, especially with weak signals. Below are some suggestions to try and improve reception.

Make sure the television antenna produces a clear signal under normal operating conditions (i.e., at home plugged into a standard 110 AC wall outlet). Also, ensure that the antenna cable is adequately shielded and of good quality.
Try altering the positions of the inverter, antenna cables, and television power cord.  Add an extension cord from the inverter to the TV so as to isolate its power cord and antenna cables from the 12-volt power source.
Try coiling the television power cord and the input cables running from the 12 -volt power source to the inverter.  Affix one or several "Ferrite Data Line Filters" to the television power cord. Ferrite Data Line Filters can be purchased at most electronic supply stores including Radio Shack - Part Number 273-105.  Try grounding the inverter with an 18 AWG (minimum) wire, using as short a length as possible.

Safety Features

The LED Indicator light will turn from GREEN to RED and the inverter will automatically turn itself off when:
   1.  The power input from the battery drops to approximately10 volts. (When the power input drops to
        approximately 10.5 volts, an alarm will sound for an extended period).
   2.  The power input from the battery exceeds 15 volts.
   3.  The continuous load demand from the equipment or appliance being operated exceeds the inverter’s power capability.
   4.  The case temperature exceeds 145 ºF.