On Friday, May 1, 2015 at 12:33:01 PM UTC-4, wrote:
On Saturday, May 24, 2014 at 9:11:09 AM UTC-6, trader_4 wrote:
On Saturday, May 24, 2014 10:53:29 AM UTC-4, sms wrote:
On 5/22/2014 4:54 AM, DerbyDad03 wrote:

I bought this inverter at you-know-where. I will be calling the tech

support number given in the manual, but I thought I'd run my questions by

you folks also.

Keep in mind there are two sides(so to speak) of the inverter: 1. the 12 volt side and 2. the 120 volt side. The 12 volt side needs 10 times the amps to provide the same watts as what you see on the 120 volt side. Watts = volts X amps or if you do a little algebra Amps = watts/volts. So, if you are wanting to run a 120 volt electrical device, say a single 100-watt lightbulb, that pulls 100 watts at 120 volts then on the 120 volt side you have 100 watts/120 volts = 0.83 amps ON THE 120 VOLT SIDE...but on the 12 volt side that same 100 watts is pulling 100 watts/ 12 volts = 8.3 amps! So your 1.0 amp air mattress at 120 volts is pulling 10 amps from the 12 volt side. If you are going to run a hand drill that pulls 7 amps of 120 volt juice then it will pull 70 amps of 12volt juice. For a 1000 watt inverter measured on the 120 volt side you have to wire the 12 volt side with a wire size that will carry 1000 watts/12 volts = 83.3 amps!! To run 80 amps 10 feet you need an absolute minimum of 4 guage wire. And I say minimum because the calculations above do not provide any safety factor, just the minimum mathematical value. Wire guage capacity tables at given voltages are all over the internet.

Old thread.

I agree with what you're saying above. What I disagreed with was:

"You may need the proper gauge wire even when you're operating the
inverter with a load that is far lower than it's capacity. "

Which seemed to be saying that you need wire that is rated for the
max capacity of the inverter, even if the actual load is far less.