My inverter only runs when the refrigerator needs to cool. Inverter also has a solid state relay so it can be turned on when I need 120V in the power shed. I decided to add a timer so the inverter can stabilize before powering the fridge. I have a perfect DIN mount timer relay for this. I can't find it or I didn't pack it. My box of modules did have some timers which would let the fridge run for 999 seconds, almost 17 minutes. Not long enough in the morning. Decided to make a RC timer with a FET and relay. Then remembered all these voltage relay boards that cost $1.70 each and decided to use one of those. It does the job and gives me a visual as to when it will turn on. That mess of wires is just for the refrigerator now.
Unlike my other voltage relays, this one has an input resistance of 21K ohms. That gave the low voltage reading of 6V maximum. I changed the timing resistor to 10K and now the voltage will now rise to 9.4V. I changed the turn on voltage to 7.5V to make the timing about the same. With the resistance of the voltage monitor so low, the 2K load resistor has been eliminated.
The math never fails. I measured th input of the voltage monitor and it is an unusually low 21K ohms instead of the 80-100K I had expected. So, 6V is just about what you would expect. That monitor can accept AC or DC and I suspect they wanted to keep the diode current high enough. I use one of these to monitor 60V and at that voltage they are dissipating 0.17W in a 1/8W resistor. Chinese engineering, it will work for a while! Now I don't really need that 2K bleed off resistor.
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My inverter only runs when the refrigerator needs to cool. Inverter also has a solid state relay so it can be turned on when I need 120V in the power shed. I decided to add a timer so the inverter can stabilize before powering the fridge. I have a perfect DIN mount timer relay for this. I can't find it or I didn't pack it. My box of modules did have some timers which would let the fridge run for 999 seconds, almost 17 minutes. Not long enough in the morning. Decided to make a RC timer with a FET and relay. Then remembered all these voltage relay boards that cost $1.70 each and decided to use one of those. It does the job and gives me a visual as to when it will turn on.
That mess of wires is just for the refrigerator now.
Unlike my other voltage relays, this one has an input resistance of 21K ohms. That gave the low voltage reading of 6V maximum. I changed the timing resistor to 10K and now the voltage will now rise to 9.4V. I changed the turn on voltage to 7.5V to make the timing about the same. With the resistance of the voltage monitor so low, the 2K load resistor has been eliminated.
How is the the 100k resistor connected? Is it connected in parallel or linked to the 2k resistor
The math never fails. I measured th input of the voltage monitor and it is an unusually low 21K ohms instead of the 80-100K I had expected. So, 6V is just about what you would expect. That monitor can accept AC or DC and I suspect they wanted to keep the diode current high enough. I use one of these to monitor 60V and at that voltage they are dissipating 0.17W in a 1/8W resistor. Chinese engineering, it will work for a while! Now I don't really need that 2K bleed off resistor.