Installation
Needed for installation - not included:
Mounting hardware for the inverter
Tools for mounting and electrical wiring
Mounting
Step #1: The STP-325 should be mounted on a solid flat surface capable of handling the weight of the unit, with space around the unit for ventilation. It is very important that the unit be secured using the proper sized mounting hardware (not included) to keep the unit from moving around or becoming loose in emergency situations. Do not block fan opening!
CAUTION: The power inverter must be mounted securely in any type of moving vehicle. In an emergency situation, if the power inverter is not securely mounted, it could cause bodily injury
Connection to Power Source
The STP-325 requires connection to a standard 12 volt DC power source such as the batteries found in most cars, trucks, RVs and boats. The power source must provide between 11 and 15 volts Dc and be able to provide sufficient current to power the load. At full power the STP-325 will draw about 30 amps.
When the load exceeds 150 watts, use the cables with alligator clips for direct connection to the 12 volt battery. WARNING: When connecting cables, a spark may occur. This is normal. To prevent explosion from the battery gasses, when connecting jumper cables, always connect the wires to the inverter first.
To connect the STP-325 to your 12 volt battery (Figure1):
1.Make sure both alligator clips are disconnected from the battery.
2.Connect the red (+) wire to the positive (+) terminal on the STP-325 and the black (-) wire to the negative (-) terminal.
3.Connect the red (+) alligator clip to the positive (+) battery terminal and the black (-) alligator clip to the frame or engine of the vehicle.
Figure 2
Figure 1
To connect the STP-325 using the cigarette plug adapter (Fig. 2):
The STP-325 also comes with a cigarette lighter plug for easy connection to the power source, Use the cigarette lighter plug, only when powering loads less than 150 watts. The tip of the plug is positive and the side contacts are negative.
1.Make sure the cigarette plug is not plugged in.
2.Attach the red (+) lead to the positive (+) terminal on the STP-325 and the black (-) lead to the negative (–) terminal as shown in Figure 2 above.
3.Plug the cigarette plug into the cigarette socket in the car. Push firmly for a good
connection.
Once connected to the 12V power source, proceed to Testing the Power Inverter
Testing the Power Inverter
Make sure the 12 volt power source is wired properly to the power inverter. With nothing plugged into the 115 VAC outlets, turn on the power switch of the STP-325. If the green power light does not come on, turn the power switch off and check your wiring and external fuse.
With the inverter turned off, plug the appliance you want to use into the 115 VAC power outlet on the unit. Turn on the power switch of the STP-325. Turn on the appliance. The appliance should now be operational.
Operation
Equipment Power Usage
It is important to use only products that draw less than 325 watts with the STP-325. Use of products greater than 325 watts may either cause the protection circuitry of the STP-325 to shut down or the fuse to blow. Repeated use of excessive power draw can cause failure of the STP-325.
How to calculate power usage.
Most products have a power rating on them such as 45 watts. Others may be marked with their current draw, such as .9 amps. To convert the current to watts multiply the current by 115. Thus .9 amps x 115 = 104 watts.
Turn on the STP-325
Plug the appliance you want to use into the 115 VAC power outlet on the STP-325 (see the chart below for suitable appliances to use with the STP-325). Turn on the power switch of the STP-325 so the green power light is illuminated. Turn on the appliance. The appliance should now be operational.*
Typical Appliance | Current Draw |
Cell phone charger | 20 watts |
Camcorder | 23 watts |
VCR | 40 watts |
Soldering iron | 45 watts |
Laptop computer | 75 watts |
Small stereo system | 150 watts |
19” TV | 160 watts |
Small power drill | 250 watts |
Battery Life Chart
Power | Approx | Typical operation | Typical operation time with |
Usage | 12 volt | time with 50 amp- | 100 amp-hr. car battery |
| current | hr. car battery | |
100 watt | 9 amps | 5.5 hours | 11 hours |
200 watt | 19 amps | 2.6 hours | 5.2 hours |
*Note : Some products such as televisions draw a high surge current to start up. If the appliance does not operate and the inverter turns off, you may need a larger inverter. Check that the battery and the 12V wiring to the inverter is large enough to handle the current draw. Be sure the battery is fully charged. You may need to turn the power switch on the STP-325 ON and OFF a few times to get the appliance “started”. Some motors and televisions may require this technique to get them operational.
Important: The STP-325 will not operate most appliances designed to produce heat such as hair dryers, heaters, toasters, and coffee makers. The STP-325 can draw up to 30 amps from your car’s battery when operating. If you are using it for extended periods of time, you will want to operate your car occasionally to maintain the charge in your car’s battery. The STP-325 will also draw a small current - less than .25 amps - when not operating, so it should be disconnected from your car’s battery if your vehicle will not be used for a few days.
Lights and Alarms
Power Indicator (Green)
This light is illuminated when the inverter is turned on and is operating normally. If this light goes out, either the 12 volt power supply is missing (possible blown fuse) or some fault condition has occurred. These fault conditions include: output overload, output short circuit, low input voltage and over-temperature of the unit. This can happen if a device has a large start-up surge, if an appliance (like a drill or saw) is stalled or if the inverter does not have a circulating supply of cool air.
Overload Fault Indicator (Red light )
The red light is illuminated when a current overload fault is detected. An overload fault occurs when the power draw exceeds the inverter’s maximum capability
An under-voltage fault (beep)
An under voltage fault can occur when the input voltage reaches about 10.2 volts. The STP-325 will sound a continuous alarm and shut off when the input voltage drops to 9.6v to protect your battery from being completely discharged.
An over-temperature fault
An over temperature fault occurs when the STP-325 internal circuitry gets too hot due to overload or improper air circulation. The STP-325 will turn off the green power light.
Fuse Replacement
Cigarette Plug fuse (see figure 3)
If you overload the STP-325, it is possible to blow the fuse in the cigarette plug. If this happens, unplug the cigarette plug from the power source, wait for the tip to cool and unscrew the metal tip on the plug. Remove the tip. Remove the fuse and install a new fuse rated at 15 amps. Never use a fuse greater than 15 amps. Replace the tip and screw firmly but do not over tighten. Always determine why the fuse blew and remedy the problem before using the STP-325 again.
Unit fuse (see figure 4)
If the fuse blows, disconnect both power leads from the battery. Remove the protective cap by pulling straight up. Next, remove the fuse by pulling straight up. Install a new 35 amp fuse and replace the protective cap. Never use a fuse greater than 35 amps. Always determine why the fuse blew and remedy the problem before using the STP-325 again.
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| | | | Figure 3 | | | Figure 4 | | |
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| | | | Troubleshooting Guide |
| Problem | Possible cause | Solution |
| Unit does not | Input voltage is below 10V | Attach to proper power supply. |
| operate. | | | | | | | |
| Fuse is blown. | Determine cause for fuse |
| | | |
| | | | | | blowing and then replace the |
| | | | | | fuse feeding the inverter. |
| Unit operates for | Load is trying to draw too | Be sure the load is less than the |
| a short time and | much current. | rated watts of inverter. Remove |
| turns off. | | | excessive load. Turn inverter off |
| | | | | | and then on |
| Unit operates for | Inverter is in thermal | Allow inverter to cool down. Turn |
| a while and gets | shutdown mode. | the inverter off and on to reset. |
| hot and shuts off. | | | | | | | |
| Low battery alarm | Input voltage is below | Make sure car engine is on. |
| is on. | 10.2 volts. | Check condition of wiring. |
| | | | | | Battery may be low and needs |
| | | | | | recharged. |
| Television and | RF interference from | Position the power inverter and |
| stereo | power inverter | wiring as far as possible from |
| interference. | | | electronic equipment, antennas |
| | | | | | and cables. |
| | | | | | Re-orient as necessary. |
| 115 VAC Output | Modified sine wave output | Use a true RMS meter like a |
| voltage reads | can cause an incorrect | Fluke 8060A or Triplett 4200 to |
| incorrectly. | reading on a typical | measure correct voltage. |
| | | | multimeter. | | | | | |
Product Specifications
Max. continuous power output | 325 watts |
Surge (peak) power output | 650 watts |
Input voltage range | 11 to 15 volts dc |
No load current draw | <0.25 amp |
Full load current draw | 30 amps |
Low battery alarm/shut-down | 10.2/9.6 V, +/- 0.5 V |
Efficiency | 90% |
Output | 115VAC, 60Hz, modified sine wave |
Weight | 2 lbs. |
Size | 7” x 4.3” x 2.0” |
