Unit was showing low output voltage when under large load. I emailed WindyNation of the situation and was given good advice that solve the problem. I was using #4 power cable to power the inverter and WindyNation informed to use #2 power cable. Inverter working very good now. Great service from WindyNation.

Great quality, strong battery cable connector. individual switches for each outlet. Very strong construction. it's work my refrigerator, 2-ceiling fans, 10 bulbs energy saver, 2-wall fan, 1-49" LED tv, 1-30" LED tv, internet router and the Xbox simultaneously with no problem. @ Puerto Rico after hurrican Maria. 09/20/2017

Using during hurricane María aftermath in Puerto Rico. Real pure sine. Works great - you can really tell the difference from modified sine to this. Damaged 2 laptops using modified sine before jumping to pure sine. Thinking of purchasing a second one as a backup. Maintains solid good energy throughout.

Inverter would work well for an application where the devices are not concerned with balanced power.

This inverter appears to function like any other cheaper inverter. There is 60vac present on the neutral plug and 60vac present on the hot plug, referenced to ground. This is not the same as what comes out a US outlet. This inverter may work well for some applications, but it would never work where the neutral and grounds are bonded together (like in a home electric panel). They claim this is rated for "off grid" locations. Well if you use a standard electrical panel, within the panel neutral and ground are bonded together. If you have this setup, this inverter will be destroyed.

Here are my test results using a Fluke 87V.
VertaMax 1500watt Inverter with 12.8vdc input, 60w AC trouble light plugged in, I show 53.7VAC between neutral and ground of the AC plug and 50.98VAC on the hot to ground. AC outlet ground, inverter chassis and 12v return are all bonded together (as one would expect).

This presents two problems.
1) the total voltage tested by my RMS multimeter is only 104VAC. This is way less than 115vac advertised.
2) The AC neutral has power on it. I would expect this out of a modified sinewave inverter

Doing the same test with a competitor (Dimensions Magnum Sensata 12/1500 N inverter) I get the same as what comes out of a standard US outlet. I show 119vac from hot to ground. Neutral to ground is 12millivolts ac (essentially nothing). This is a true pure sign wave inverter.

For most applications this will work just fine, to power a drill or equipment in the field from your vehicle. Just be careful of the neutral and ground AC bonding issues.

DIY home UPS with golf cart batteries & trickle charger. Reliable, steady pure sine wave signal is needed for motors and compressors. Runs furnace and refrigerator without breaking a sweat, no problem.