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Inverters up to 450 Watts can plug into a cigarette lighter.
Larger ones require hard wiring to the battery.

AC Watts divided by 12 x 1.1 = DC Amps.
Source: FAQ : InverterDirect.com, DC AC Watt Power Inverter

Higher power inverters (1000-4000 watt)  wires should be no longer than 6 feet
long, and preferably 3 feet or less.

Plan for a voltage drop of less than 0.5V at maximum load.
You must add the +ve cable length and the -ve length together.
General Recommendations from DonRowe.com: FAQ's
Inverter Size
Amps Cable Gauge
< 3 ft 3-6 ft 6-10 ft
750 69 6 4 2
1000 92 4 2 1/0
1500 138 2 1 3/0
2000 183 1/0 2/0 250
2500 229 1/0 3/0 350
3000 275 3/0 4/0 500
See: Wire Size Specs

Battery requirement:
2,000 wattHours system would require 4 x200 AmpHr (Ah) of battery capacity.

A 1,000 watt inverter:
Time @ 1,000     battery Ah
       1 hr        200 Ah
       2 hr        400 Ah
See Power Requirements

Advantages of Pure Sine Wave inverters

  • Inductive loads like microwave ovens and motors run faster, quieter and cooler.
  • Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.
  • Prevents crashes in computers, weird print out, and glitches and noise in monitors
. Some devices which will not work with modifided sine wave inverters:
  • Laser printers, photocopiers, magneto-optical hard drives
  • Certain laptop computers (you should check with your manufacturer)
  • Some fluorescent lights with electronic ballasts.
    If the bulb appears to be too bright, or fails to light, do not use the lamp with an inverter.
  • Certain rechargers for small nickel-cadmium batteries.
    e.g. Small, battery-operated appliances such as flashlights, cordless razors and toothbrushes that can be plugged directly into an AC receptacle to recharge.
  • Power tools employing "solid state" power or variable speed control
  • Some battery chargers for cordless tools
    DO NOT plug in battery chargers for cordless power tools if the charger carries a warning that dangerous voltages are present at the battery terminals.
  • Some new furnaces and pellet stoves with microprocessor control
  • Digital clocks with radios
  • Sewing machines with speed/microprocessor control
  • X-10 home automation system
  • Medical equipment such as oxygen concentrators
The majority of portable appliances do not have this problem. Most portable appliances use separate transformers or chargers that plug into AC receptacles to supply a low-voltage DC or AC output to the appliance. If the appliance label states that the charger or adapter produces a low-voltage DC or AC output (30 volts or less), there should be no problem powering that charger or adapter.

Pure sine wave converters are more expensive:
Watts Sine Wave
Modified Pure
150 $25 $120
300 35 160
1000 80 480
1500 120 550
2000 280

Using the Inverter:
Use deep cycle (marine or RV) batteries which will give you several hundred complete charge/discharge cycles. If you use the normal vehicle starting batteries they will wear out after about a dozen charge/discharge cycles. If you do not have a deep cycle battery, you run the engine of your vehicle when operating the power inverter. When operating the inverter with a deep cycle battery, start the engine every 30 to 60 minutes and let it run for 10 minutes to recharge the battery. See www.donrowe.com/inverters/puresine.html

Manufacturers - Models

Mfg. Watts Cost score Where Notes
Samlex 150 $105 EcoDirect Pure sine wave
Cobra CPI 1575 1500 $105 3.5 Amazon bad review
EMS 1500 $220 Napa
Power Bright 1500 $140 5 Home Depot
Cen-Tech 2000 $160 3.5 Harbor Freight
Whistler 2000 $156 3.5 Amazon
Vector 3000 $349 InvertersRus.com bad review
Power Bright 3500 $327 5 Home Depot
Ramsond Sunray 3000 $580 Home Depot pure sine wave
Modified Sine Wave Power Inverters | The Inverter Store

Cable and Fuse Kit for Inverters Over 1800 Watts $180 2000-3000 Watt Power Inverter 2x 3" #4 AWG Cable Kit $35

Power Inverters Xpower Portable Power Xantrex Inverter - Inverters

Deep Cycle Batteries
Power Inverter Links at 4lots.com
Home Power Inverter | electroschematics.com
FAQ : InverterDirect.com, DC AC Watt Power Inverter | inverterdirect.com
Power Inverters for Solar Energy Systems, (System Overview, Batteries, )
Electrical Wire Size Specs
Power Requirements for appliances

last updated 28 Apr 2008