The vehicle is a 2006 Chevy Colbalt and when the vehicle is started, the volts spike to 14.8 after about a minute. The inverter works fine when the vehicle is not running. It is connected properly. Is there some kind of protection device that can be connected between the vehicle's battery and the inverter that would limit the high voltage to the inverter? The vehicle's charging system is working properly
Short of shutting the inverter off momentarily, there is not a simple answer. because you could slightly modify the inverter's over voltage reference IC, but that requires knowledge of the inverter that the manufacturer does not want you to know normally.
if you are running the inverter off a second battery, you
could isolate that second battery from the system through any number of
time delay relays, time delay circuits comparable to intermittent wiper
circuits.
However, if you are capable with a soldering iron, MOSFETs can be utilized as a voltage variable resistor. They can be in a parallel array to increase current. You need to know what current draw is by the inverter with the normal load.
Once you know that current, you can select a MOSFET of sufficient "Constant Current" or pair of them and wire them as "Voltage variable resistor."
The circuit actually does work, the resistor is adjusted until you aproach the "pinch off zone" and tweak it to the point you want to operate with. The MOSFETs will need to be on a heat sink, any you can even wire a switch across them to short across them to remove them from the circuit. The image only shows one MOSFET, but they can be operated in parallel for more current capactiy. Which why the constant current rating of the MOSFET needs to be known. The type of MOSFET is not critical, it can be a trench fet, hexfet, etc. You should plan for double the current draw in your MOSFET selection for purposes of a design centered value. You can use up to about 5 MOSFETs from that one pot. For extra margin in the design you could add 0.1 ohm (2 Watt) resistor in series with each MOSFET to balance current through the MOSFETS, although MOSFETS will self equalize to a point. When they heat up their internal resistance goes up so thermal runaway is not normally an issue.
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