POWER INVERTERS convert DC from your battery to 120 volt AC for lights, outlets and most appliances, without starting a generator.

DC OR AC APPLIANCES? Folks with the smallest solar power systems and few, simple appliances may have no inverter, and use low voltage DC for all lights, radio, TV, and water pump. People using the largest solar power systems sometimes use AC power from an inverter for everything. Usually it is most practical to use both inverter AC and some direct battery DC. AC is most practical for regular household outlets and lights, because most AC appliances are better quality, easier to find, and lower priced than 12 volt DC versions. But a few special DC appliances can save a great deal of energy. Items that drain a small amount of power over long hours can use far less power if DC powered. Some examples would be ceiling fans, phone message machines, motion sensing lights, intercoms, or alarms. This catalog features special low power washing machines, refrigerators, freezers, lights, and 120 volt well pumps specially selected to work with inverters, and to avoid excessively draining battery power. Also see the introductions to our Refrigerator section, DC Appliance section, Pump section and Lighting section for discussions of DC vs. AC applications. 

GENERATOR POWER SYSTEMS, even without solar modules, benefit from inverters too. You can fast charge a large battery bank for a few hours a day while the generator runs the water pump, clothes washer, shop tools etc. Later, when only a few watts are needed for lights or TV, the battery and inverter supply that power without the generator. This way power is available 24 hours a day at the turn of a switch but the generator runs only a few hours a day. This saves on generator maintenance, and life gets better! (But it is difficult to get batteries fully charged with just a generator, and serious battery problems are common with just a generator. Backwoods Solar advocates using primarily solar charging).

TRADE-UP TO A BETTER INVERTER We accept trade-ins of used inverters bought at Backwoods when you need a larger or better model. 

USED INVERTER trade-ins are often available. Call, or see our Backwoods Bargains list on our newsletter page.

MODIFIED SINEWAVE OR TRUE SINEWAVE?

MODIFIED SINE WAVE is a sales term used for a modified square wave type of AC power which is not quite the same as power company electricity. Modified wave inverters are lower cost, slightly more efficient, and almost all appliances work fine with them, though some may hum louder. But a few sewing machine speed controls and some Apple computers have difficulty on modified Sine Wave. It can also damage photocopy machines, laser printers, and some cordless tool rechargers. Recently we found the first TV that would not run on any modified wave inverter. Battery chargers in the DR model modified waveform inverters may require the highest quality generator (about $3000 and up) to charge effectively.

TRUE SINE WAVE inverters supply power of better quality than the power company, and work correctly with any appliance. Battery chargers in true sine wave inverters work well with any generator. Xantrex SW+ series and Outback  inverters can automatically start and stop a generator when extra battery charge is needed. A low cost Samlex true sine wave inverter might be used when you have just a few smaller appliances that require true sine wave power.  

SIZE of inverters ranges from under 100 to over 5000 watts. This rating indicates the largest wattage appliance or combination of appliances that the inverter can operate continuously and at the same time. Surge rating is well above the normal power rating, to run larger appliances for a short time, or to start heavy motors. Determine the highest wattage appliance or combination you want to run without using a generator. The chart below shows the range of inverter sizes.

STANDBY CHARGER means the inverter becomes a battery charger when power is supplied to it from a generator or utility source. An automatic transfer switch within the standby inverter connects outside power through to the house circuits to power your appliances while also using it to recharge the batteries.

EFFICIENCY of most power inverters is 85 to 95%. Even though 5 to 15 % of the battery power is lost in converting up to 110 volt AC, the cost savings in AC wiring and other appliances over the cost of DC equipment often makes AC the better choice.

SEARCH MODE is a useful feature in some inverters to automatically shut down to nearly no power use whenever all appliances and lights are off.

GO TO MODIFIED WAVE INVERTER PRODUCTS
GO TO TRUE SINE WAVE INVERTER PRODUCTS  

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INVERTER COMPARISONS

GO TO MODIFIED WAVE INVERTER PRODUCTS
GO TO TRUE SINE WAVE INVERTER PRODUCTS  

INVERTER ACCESSORIES

BATTERY CABLES

Inverter performance and safety depend on using cables sized for very high battery currents, in lengths no longer than 10 feet. The cable end terminals and inverter bolt connections must be tight or enough heat can be generated to melt the cables and inverter input bolts, and to start fires. 

These large cables are finely stranded for flexibility and have lug ends industrially pressed on to fit terminal bolts on inverters. Use a fuse, powercenter, or breaker box with these cables. 

Powercenters use just one set of cables for DC cables to battery and cables to inverter where 10 feet total length is usually enough.

The Portawattz and Exeltech 250 inverters includes cable receptacles, not studs, on the inverter. A single BC10-2 cable at half the pair price can be cut in two, to make a pair of battery cables with lugs used only at battery end, for these inverters.

Boxed pairs of cables, one for positive, and one for negative.

For all inverters 600 watts to 1000 watts BC 10-2 copper 2 gauge 10-foot pair, lugs on all ends: (shipping $8)  $70
Single BC 10-2  Single cable: cut it in half for inverters with cable receptacles, not studs:  $35 (shipping $5)
For 12 volt 1000-1500 watt; 24 volt 2000-3000 watts; 3600-4000 48 volt BC 10-2/0 copper 2/0 gauge 10-foot pair, lugs on all ends:  $95 (shipping $10)
For 12 volt inverters over 1500 watts; 24 volt over 3000 watt; 48 volt over 4000 watts BC 10-4/0 copper 4/0 gauge 10-foot pair, lugs on all ends:  $140 (shipping $14)

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INVERTER TRANSFORMERS

Xantrex T240 TRANSFORMER

Changes 120 volt to 240 volt -- or -- 240 volt to 120 volt. Rated 4.5 Kilowatts. For operating 240 volt appliances from 120 volt inverter power, or taking a 240 volt generator output down to 120 volts while maintaining full watt rating of generator.

Can be used to power existing 240 volt pumps, but Backwoods Solar suggests using a 120 volt pump if feasible. See our pump section or call for suggestions.

Includes a two pole 25 amp output breaker and cut-outs for up to 6 additional breakers, knockouts for conduit connections, and accepts 14 gauge to 2 gauge wire. Size 6-1/2 x 21 x 7 inches. Weight is 40 pounds.

I-T240:  $495 (shipping $32)

VOLTAGE BOOST FOR BATTERY CHARGING

If your generator doesn't give at least 2/3 of the rated charge amps from automotive battery chargers or modified wave UX and DR model inverter battery chargers, it's taking too long to get your battery fully charged. Some generators costing under $2500 lack  in peak voltage. These voltage boost transformers can restore the full battery charging amps and reduces charge time.  Use a DC ammeter like M-DIG AMP or Trimetric to confirm the need for this cure.

10% VOLTAGE BOOST TRANSFORMER

 Hard-wires between generator output and charger/inverter input.  5000 watt rated.  1 yr. warranty

I-10% BOOST:   $145 (Shipping $18)

                                            OUTBACK PSX-240 TRANSFORMER

This 6kva auto transformer with cooling fan can be used for step-up, step-down, generator and split phase output balancing or as a series stacked inverter to load balancing auto-former. Incorporating a transformer with 120v 30 amp primary and secondary side, a temperature activated cooling fan and a 25 amp dual breaker in a steel enclosure. the PSX-240 is ready for your custom 120 or 240v 60hz only system.

I-PSX240..................shipping $32................$520

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