Electric Parts and Accessories
Statpower Technologies - Manufacturer
Statpower Technologies is a leader in the development, manufacture, and global marketing of mobile and backup power solutions (including DC to AC power inverters and smart battery chargers).
Their VISION is to provide innovative products that will service these markets and their enormous need for clean and cost-effective power worldwide.
Power inverters and battery chargers are what Statpower is all about. Having pioneered the use of high frequency switching technology, Statpower developed the first complete line of power inverter products based on this technology.
Sine Wave Inverters
Sine Wave Inverter-Chargers
Inverter Installation and Use
Inverters are a wonderful thing for most boaters to have onboard, enhancing their enjoyment of the boat and adding a unique level of safety. In order to be useful and safe, however, inverters must be properly installed and used with care.
The battery bank and wiring in the boat must be capable of handling the extra loads that an inverter will impose on them. Watching a movie on the 120-volt TV and VCR at 720 watts doesn’t sound like much, only 6 amps of power at 120 volts. But since the relationship between 12-volt and 120-volt systems is roughly 10 to 1, disregarding inefficiency in the inverter and batteries themselves, this combination is using 60 amps of 12-volt power, and a two hour movie will drain the standard Group 27 battery dry. If your battery banks are too small, or too tired, to run such large loads, take the time to enlarge the capacity and replace worn batteries at the same time you install the inverter.
In addition, most boaters are surprised to find the cables on the inverter must be very large to carry the massive amounts of 12-volt power. If the cables, terminal posts and battery switch in the boat are not rated to carry the same loads as the inverter, they must be replaced with larger capacity parts.
A third item to investigate is the battery re-charging system.
While most inverters can draw such massive amounts of power out of the batteries, those with built-in battery chargers can replace that power quickly and easily when the boat is plugged back into shorepower or the genset is turned on. Boats away from the dock for long periods without a motor generator will have to rely on the main engine’s alternator, solar panels, wind or water generators or some other method of recharging the batteries. If you need to add charging capacity in the form of a high-output alternator or alternative energy source, the installation of the inverter would be a good time to do it.
Choose a dry and well ventilated area to install your inverter as they do not like water and can generate a great deal of heat. Inverters are surprisingly heavy make sure that the shorepower cord and all battery cables are disconnected, all switches and circuit breakers are in the off position and that you have all the parts and tools necessary. Read the manufacturer’s installation guide several times, make sure you understand it and follow it throughout the process.
Locate your inverter as close to the batteries and/or main battery switch as possible. The 12-volt cables should not be extended if possible, if they must be lengthened, use the same gauge wire, or heavier, as that supplied on the inverter.
A major safety item in all inverter installations is a fuse in the main 12-volt input line. All manufacturers require this fuse but few, unfortunately, supply it as standard equipment. Use the installation manual to determine the size required.
Most inverters have an internal automatic switch that senses when 120-volt power is present and either shuts the inverter off or changes it over to battery charging mode to make use of the available power. If yours doesn't have automatic switching, you may require a "Ship/Shore" safety switch.
Using an Inverter
Inverters have exceptional ability to operate any 120-volt appliance. Most you can plug in and use as if you were at home but there are a few exceptions and minor limitations. Many inverters have a sensing unit that tells them when there is no 120-volt demand. This puts them into a "sleep" or "idle" mode until an appliance is again turned on, which puts the inverter back to work again. This circuitry makes power available instantly and yet saves power when no demand is present. A very small appliance, such as re-charging the battery on a mobile phone, however, is often below the threshold setting to bring the inverter out of its sleep mode. In this case, plug in several items at once to wake the inverter up, or turn on a small light that will draw enough to keep the inverter awake.
Almost all inverters operate with a "square wave" 120-volt output rather than the true sine-wave output of household power. The square wave will operate all motors, heating elements and converters, but it has two oddities with which you need to be familiar. First, the standard analog gauges on your panel and your portable voltmeter cannot interpret this waveform properly. They will indicate that you are operating on about 90 volts. This is normal and harms nothing. If a true voltage reading is desired, an RMS (root mean square) meter must be used, all professional electricians own one and many of them refer to it as a Fluke meter after a major brand of electrical instruments.
Also, electrical appliances containing electronic timing devices often cannot read the inverter’s square wave. The best example of this is bread makers that have timers to establish the mixing, rising, kneading, and baking sequence. Most items of this type will not operate from the standard inverter and must have a true sine wave unit for proper power. Motorized electric clocks or relays work just fine.
The main consideration with an inverter onboard is to have good monitoring tools for your batteries and 12-volt system and to develop the habit of checking them often. Most inverters do have low-voltage cutoffs that will stop drawing power when the ship's voltage becomes too low. But by that time, there's not enough juice left to start the engine either.
Keep track of the power you use or install a monitoring computer to do it for you. Low battery alarms are an inexpensive alternative. Have good 12-volt guages and learn how to interpret them. Otherwise, that great movie and popcorn may drain the batteries and leave you calling for a tow back to the dock.
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