I bought a 2000w Nature Power pure sine inverter from camping world.I had my local rv dealer install the inverter (and a power tongue jack) that I bought a CW.It was $200 in parts and $500 in labor.He put a 3 way switch in the camper (shore power/inverter/battery).However, when I try to run the 900w microwave, after about 4 seconds I get a beep, and the microwave shuts off.I have 2 six volt batteries fully charged. They've been plugged in for 3 days.I'm guessing the beeping is a low voltage alarm.Why won't this inverter power the microwave? Could it be too small gauge of wire from the inverter to micro?I'm kicking myself for spending so much money on this thing if all it will do is power the tv.

Could it be too small gauge of wire from the inverter to micro?That's the most likely reason. Measure the voltage at the inverter as the microwave shuts down, then do it again at the battery, and see how much you're losing in the wires.

Read the label or the manual for the microwave oven.It will tell you how much current (Amps) it draws. Multiply by 120 to determine the AC power drawn from the inverter.The power rating on a microwave oven is the output power from the magnetron tube and they are only about 50% efficient.

MP soldier wrote:He put a 3 way switch in the camper (shore power/inverter/battery). Why won't this inverter power the microwave? Could it be too small gauge of wire from the inverter to micro?I have 2 six volt batteries fully charged.I see several issues here.2 batteries is a bare minimum (and often not enough) to run high-wattage devices like MW. How old are the batteries? Just because they're full charged doesn't mean they're in good enough shape to sustain a big discharge. It's likely the wires from the batteries to the inverter are too small or too long. It's almost unheard of that the wire to the micro is too small - if it were it wouldn't run on shore power.Wayne might be thinking you said the wire from the battery to inverter.Also, the switch.. depending on where that is in the circuit could be affecting performance. To add insult to injury, that brand of inverter is not exactly top of the line...but I don't think it's your problem.

A "standard \" three way switch will not do what you posted.Can you post the make and model of the switch installed?

Why won't 2000w inverter run 900w microwave? | Good Sam Community

144 Replies

ol_Bombero-JC
Explorer
Jun 12, 2014
Wayne Dohnal wrote:
Could it be too small gauge of wire from the inverter to micro?
That's the most likely reason. Measure the voltage at the inverter as the microwave shuts down, then do it again at the battery, and see how much you're losing in the wires.

.

"marcsbigfoot20b27" -

Thanks for the 2nd post tip (above)!

Skipped to the last & saved about 14 pages and a year's worth of hash and re-hash...:C

~
3_tons
Explorer III
Jun 12, 2014
0000 welding cable bends fairly well...
JiminDenver
Explorer II
Jun 11, 2014
BFL13 wrote:
JiminDenver wrote:
My big inverter uses two sets of cables to deliver the power.

Yes, my 2000w Vector is using the Vector wiring kit for that which is a double set of #4 wires three feet long. Cobra has the same way.

You can use one big ANL where both wires meet at the battery end or use a smaller ANL on each of the two pos wires near the battery.

I'll be using four 51 inch 2 awg starter cables.
CJW8
Explorer
Jun 11, 2014
marcsbigfoot20b27 wrote:
Damn, 140 posts and 1 year later just to get to what was said in the second post. :?

Exactly what I was thinking. Now to see if the dealer will fix his bad install over a year later.
marcsbigfoot20b
Explorer
Jun 11, 2014
Damn, 140 posts and 1 year later just to get to what was said in the second post. :?
wa8yxm
Explorer III
Jun 11, 2014
On my prosine I think CW put in zero ga (not sure actually)

When the prosine lost it's mind Xantrex suggested some things that caused me to re-read the manual on wire size recommendations.

I went to 0000 (4/0) Ga.. How do you bend it.. Well. high quality cable bends easier than the cheap stuff but still.. the answer is "With great effort".
Wet_Coast
Explorer
Jun 11, 2014
Holly smokes! How the heck can they bend the stuff?

Easy, use welding cable! I am using 1/0 welding cable for my batteries and inverter feeds. No issue at all getting the stuff anywhere I need to.
horton333
Explorer
Jun 11, 2014
MP soldier wrote:
Size Diameter in mm
OO 9.26592
6 4.11480

Pretty big difference!

And it is the radius *squared* that is important ....
Sounds like a place where a 24 volt system would make sense.
mena661
Explorer
Jun 11, 2014
MP soldier wrote:
horton333 wrote:
00 to 6 gauge is a lot worse than half, it's only 20% of the cross section!

Holly smokes!
How the heck can they bend the stuff?
It bends pretty easily actually if you get welding or boat cable.
MP_soldier
Explorer
Jun 11, 2014
Size Diameter in mm
OO 9.26592
6 4.11480

Pretty big difference!