Inverters

The inverter is a basic component on medium to large systems which converts low voltage DC power from the batteries into high voltage (usually 120 or 240) AC power as needed.

Inverters of the past were inefficient and unreliable. Today's generation of inverters are very efficient (85 to 94%) and very reliable.

Today, the majority, if not all of the loads in a typical remote home operate at 120 VAC from the inverter. The only reason to operate select loads at low voltage DC is to maximize efficiency.

Most inverters we sell produce only 120 VAC, not 120/240 VAC as in the typical utility connected home. The reason being, once electrical heating appliances are replaced with gas appliances, there is little need for 240 VAC power. Exceptions include good-sized submersible pumps and shop tools which can either be powered by the generator, step-up transformer, or possibly justify the cost of a larger or second inverter.

Two types of inverters predominate the market ­modified sine and sine wave inverters.

Modified sine wave units are less expensive per watt of power and do a good job of operating all but the most delicate appliances. Sine wave units produce power which is almost identical to the utility grid, will operate any appliance within their power range, and cost more per watt of output.

Inverter Checklist

Inverter to battery cabling. Because of the high current required on low voltage circuits, this cable is large, commonly #2 to 4/0 in size. Smaller conductors than required are unsafe and will not allow the inverter to perform to its full rating.

DC input disconnect and overcurrent protection. It is important to have a safe installation with a properly sized DC rated, UL listed disconnect. Typically the disconnect works in conjunction with a overcurrent protection device such as a fuse or breaker. These components are installed in an enclosure which can also house shunts.

Shunts - Used to read the amperage flowing between the battery and inverter, this device is installed in the negative conductor. It can easily be housed in the disconnect or its own enclosure.

AC output disconnect and overcurrent protection. If the breaker panel, which is fed from the inverter, is adjacent to the inverter, then the main breaker will serve as the inverter output disconnect and overcurrent protection. If, however, this panel is not grouped with the inverter, then a separate unit should be installed. This also holds true with AC circuits coming to the inverter from a generator or utility source. A second breaker may be needed if these breakers are not grouped.

Inverters with Built-In Battery Chargers

Many of today's inverters incorporate battery charging circuitry. This is easily and economically accomplished because of the design of most inverters. Inverters step up low voltage and change DC power to AC power. Battery chargers do the reverse of this. Additional circuitry is all that is required to add a whole second function and economically create an Inverter/Charger.

Transfer switches are also incorporated into these Inverter/Chargers so that the AC loads can be powered directly from the generator when the battery charger is operating.

From a reliability, performance, and economical standpoint, built-in battery chargers are the way to go.

Comparing Inverters

Inverters are compared by three factors:

  • Continuous wattage rating. Hour after hour, what amount of power in watts can the inverter deliver.
  • Surge Power. How much power and for how long can an inverter deliver the power needed to start motors and other loads.
  • Efficiency. How efficient is the inverter at low, medium and high power draws. How much power is used at idle.

Inverter Over current Protection, Cable and Power center Sizing Chart

Over current Minimum Power center
Brand Continuous Maximum Protection Cable Minimum
Name Model Wattage Voltage Input Amperage In Amps Size'"
Size"
Stat Power 150-12 150 12 16 20 #4
Stat Power 250-12 250 12 27 40 #2 -
Stat Power 250-24 250 24 13 20 #4
Stat Power 800-12 800 12 86 110 #2 3-202
Stat Power 800-24 800 24 43 60 #2
Stat Power 1500-12 1500 12 160 200 2/0 3-202
Stat Power 1500-24 1500 24 80 100 #2 3-202
Stat Power 2500-12 2300 12 246 300 4/0' 3-404'
Stat Power Prosine 1.2-12 1200 12 128 175 2/0 3-202
Stat Powe Prosine 2.5-12 2500 12 267 400 4/0' 3-404
Stat Power Prosine 2.5-24 2500 24 134 175 2/0 3-202
Exceltech 250-12 250 12 27 40 #2
Exceltech 250-24 250 24 13 20 #4
Exceltech 500-12 500 12 54 100 #2 3-202
Exceltech 500-24 500 24 27 40 #2
Exceltech 1000-12 1000 12 107 150 2/0 3-202
Exceltech 1000-24 1000 24 53 100 #2 3-202
Exceltech 2000-12 2000 12 214 250 4/0' 3-404
Exceltech 2000-24 2000 24 107 150 2/0 3-202
Trace/Xantrex 812 575 12 62 100 #2 3-202
Xantrex DR1512 1500 12 160 200 2/0 3-202
Xantrex DR1524 1500 24 80 10 2/0 3-202
Xantrex DR2424 2400 24 128 175 2/0 3-202
Xantrex DR3624 3600 24 193 250 4/0 3-404
Xantrex 2512 2500 12 267 400 4/0' 3-404
Xantrex 2548 2500 48 67 100 2/0 3-202
Xantrex SW2512 2500 12 267 400 4/0' 3-404
Xantrex SW4024 4000 24 214 250 4/0 3-404
Xantrex SW4048 4000 48 107 150 2/0 3-202
Xantrex SW5548 5500 48 147 200 2/0 3-202

Next - Batteries

Eco News & Resources

For the latest news on renewable energy, click here.

For More Information

Sign up here to receive our newsletter:


Privacy Policy

Solar Estimator

Want to know what your cost and payback would be on a renewable energy system?
Click here! Estimate my solar energy system.

Get Started

Click here for a quote on your renewable energy system!

Better Business Accredited www.find-solar.org connects people to solar energy professionals. NABCEP
Facebook

Renewable University | Sustainable Community | Products | Company Profile | Client Solutions

© 2009 Eco Depot USA. All rights reserved.

Internet empowerment provided by GS Multimedia