Problem with power inverter

Check where it is attached to the batteries. You might see a fuse there.

 

The fuse would be on the unit itself or somewhere on the power line leading to it but if it is beeping when you try to turn it on then it clearly has power so a fuse would not be your issue.

If you have anything plugged into it when you are trying to switch in on it may just be overloading it (drawing more power then it is rated for) and not allowing it to turn on. Unplug everything from if before switching it on and it it still fails it is probably new/defective product and you should exchange it.

 

Unplug everything from it, turn it on......does it still beep? My guess, as stated above, you are overloaded.

 

Check and clean the connections to the batteries. You might be surprised how a dirty connection will come on, then cut it off when pulling more power. So many want to run the ground to the chassis, which will cause problems. The ground for inverters should be attached directly to the batteries.
Also check the connections are tight, also at the invertor. Vibrations will loosen the connections.

 

Or is this inverter powered by a cig lighter plug? Lots of missing info to diagnose the symptoms over the internet.

Mikeeee