New project with car inverter and a few surprises!
Bought a car inverter rated for 200W online so that I can charge my laptop while on the move. But car cigarette lighter socket is rated for only 120W. Read online that if higher rating device is plugged in, an internal fuse might blow off. Technically, the no load current of this car inverter is only 0.3 A. So it should be possible to use lower power rating equipment like a laptop charger rated for 220V, 65W. In addition to a main power output socket, this car inverter has a couple of USB sockets and a USB-C PD (Power Delivery) socket. There is also a three digit display in one corner.
It has another socket on the side suitable for a cigarette lighter as well.
Before trying in the car, I wish to use this for my 160W solar panel with a 200W solar charge controller and see if it can work a pedestal fan. I did not want to cut the cigarette lighter adapter pin on the inverter and hence a cigarette lighter socket was also bought online. Now I can connect the socket to the solar charge controller and pin in the car inverter into the cigarette lighter socket. This socket comes with a lock and a suitable cable. It is supposed to be waterproof, dust proof and has a safety overload fuse.
Here is the fuse on the positive terminal wire of the cigarette lighter socket. Tried to open it up to see the fuse inside. Did not try too hard for fear of damaging it and I could not open it to see the fuse inside.
Snipped off a part of the wire with the eyelets so that I can connect them to the solar charge controller connected to my 160W solar panel and 65Ah SMF lead acid battery.
As usual, insulation from a small portion at the tip was removed using a wire stripper.
After connecting the socket terminals to the solar charge controller, the cigarette lighter adapter of the car inverter was plugged into it. The display lit up, showing input voltage as 12.8V from the battery through solar charge controller. USB ports were also lit up.
Just out of curiosity, I checked the output voltage from the power socket and I was shocked to see it as 539 volts. I had no idea on what was happening and searched online. A few possibilities came up. One is that the inverter may not be a pure sine wave inverter. If it is not a pure sine wave inverter, the multimeter may not give the proper voltage. It has been mentioned that unless the measuring device is a ‘true RMS’ capable one, it may be measuring the average voltage and calculating the RMS voltage. That works out fine if it is a true sine wave inverter, but not if it is a modified sine wave or square wave. Checked the output of another 1150W inverter which I had. That was a pure sine wave inverter and output was shown as 230V.
Tried connecting an incandescent lamp rated for 25W/230V. I had a small doubt that it might blow off when connected to ‘539V’ inverter. I was surprised once more when nothing like that happened and the lamp lit up as when connected to usual 230V mains supply. Input voltage dropped a bit when the bulb was connected as a load for the inverter. Then I tried a 70W pedestal fan. It did not work and the input voltage on the display dropped to 9.7V. I had a worry the the fan would have gone out of order due to the ‘539V’. But that was not the case. The fan worked properly when connected back to the mains as well as the 1150W inverter. One friend suggested that I should get a better voltmeter and check once again.
But why did the 70W fan not work with the 200W inverter? Why did the input voltage on the display drop so much on the display despite the fact that it is connected to a 65Ah battery which works well with a 1150W inverter with only a minimal voltage drop? Has it something to do with the coils in the fan motor, which are not there in the bulb? Is it that adequate starting current was not provided to the fan motor? Let me pause with these odd observations and ask you for any other explanations for such an outcome.