Inverter issues in 2012 volve vnl670...Help plz

A few things to check.

Cables from the inverter to the battery should be the same size as the mount holes on the inverter. They should be short as possible. Preferably less than 4 feet to avoid a voltage drop and power surges. You can use a short extension cord coming out of the inverter if need be but the supply cables must be under 4 feet to function 100%.

The unit should have a separate ground beside the two battery cables. This is usually truck chassis ground to the inverter chassis ground. There is a separate screw for the chassis ground on the unit.

Where the cables come through the truck's floor must be protected from shorts. This is done with a rubber grommet and silicone.

Connections to the batteries must be clean and free from corrosion.


If all that is followed there shouldn't be a problem. If there still is a problem then I would think one of his batteries is bad and needs replaced. Someone needs to take all the cables off the batteries and load test each one. Usually a multimeter will reveal the bad battery. The voltage reading will be lower than the rest.

I once had that problem and it was a bad battery.

 

CondoCruiser covered it well.
Batteries, btw, sometimes even come new with a shorted/bad cell. Not common, but can happen. Just an FYI for the OP.
Let me ask one thing, tho. Is he running the inverter with the truck engine on, or engine not running?
Without engine running, the voltage is approx 12.5 volts. With engine running, the alternator provides charging voltage (a boost) to approx 13.5 to 14 volts.
If the truck is not running, try operating the inverter with the engine running. Check if that makes a difference.

Also, on the cables from the battery to inverter. I'm "assuming" the shop cabled it in the proper way, with proper gauge (diameter) cables.
I would be hesitant to run a 2500 watt inverter on anything less than 6 gauge cables. 4 gauge would be even better. (higher number = thinner cable)
Make sure the shop did not wire it with too long a length a cable (as Condo said), or too thin of a cable gauge used (such as 10 or 12 gauge).

Most of the time, an inverter beeps due to inadequate voltage/amperage supplied to it, from the battery input side.
Batteries and cables are two prime suspects, as far as that goes.

 

Long story short, your truck needs to be running while microwaving unless your batts are in tip top shape. Also, do the wires going to the batt feel hot while in use? Make sure the the wires are correct size, and make sure truck is at 1000 rpms or better. Do to a lot of math and losses, a truck with a 150 amp alternator only produces about 1000 AC watts after losses at 1000 rpm. A 2500 watt inverter is over kill since you will never get more then what the batts and inverter can produce. If your batts are starting batts and not AGM, its not likly they will be able to handle the demand and thus your motor must be running to microwave. Even with the motor on you bairly have enough power.

 

Nearly all of what you say is true, however it doesn't apply to running these items off the 2500 watt inverter for a brief period of time.
If the OP was trying to operate larger wattage items for a lengthier duration, then yes, the alternator wouldn't be able to keep up.

 

Let me ask u this is the company running two or 4 cables to this inverter every one that i have seen thats 2500 watts runs two power and two grohnd plus the extra chassis ground the beeping usually happens cu of low voltage from batteries. If theyre not running proper cables that would cause it