Increasing input voltage of DC-AC inverter - possible ?
Good day folks. Some of you may remember that a while ago I wrote about a colleague of mine who likes tinkering with batteries and design all kinds of crazy devices using them. He reached out to me again and asked me if it would be possible to increase the maximum input threshold of a DC-AC inverter he's using for god knows what. The reason he wants to do this is because this inverter runs at 15v max according to the label, while the battery pack he built puts out 18v which causes the inverter to shut off - some sort of OVP on the input there.
Not really having the time and not wanting to ruin someone else's junk, I kindly brushed him off so I could think about it. What would the limitations be here or is such a hack even remotely possible ? Sounds like a window comparator to me. An IC of sorts (at the most basic level an op-amp) has a fixed reference voltage on its N/I input and a resistor divider on its inverting input (or vice versa depending on whether the output swings negative or positive when OVP is triggered). The "top" of the resistor divider goes to the input and the two resistors are calculated in such a way that when the input is under the threshold, the voltage is lower than the reference and the op-amp is not triggered. When the input causes the resistor divider's output to go higher than the reference voltage on the other input, the output swings low or high stopping the device one way or another - perhaps by cutting VCC to a switching IC. It's a fairly cheap thing so I doubt it's fancy enough to have a micro in there - THAT would be a problem since the threshold might be internally programmed !
Aside from the theory, an immediate practical issue would be the capacitors (and other components along the input for that matter) since they're very likely not rated for anything more than 16v, so those would require swapping for 25v or higher ones....
That's all I can think of TBH...doesn't sound too difficult on paper, but who knows what I'm faced with once I actually pop the cover off
It's rather small in size, so I don't think it's rated for anything higher than 200w - maybe 300 pushing it...
Any thoughts ? Cheers and thanks
Not really having the time and not wanting to ruin someone else's junk, I kindly brushed him off so I could think about it. What would the limitations be here or is such a hack even remotely possible ? Sounds like a window comparator to me. An IC of sorts (at the most basic level an op-amp) has a fixed reference voltage on its N/I input and a resistor divider on its inverting input (or vice versa depending on whether the output swings negative or positive when OVP is triggered). The "top" of the resistor divider goes to the input and the two resistors are calculated in such a way that when the input is under the threshold, the voltage is lower than the reference and the op-amp is not triggered. When the input causes the resistor divider's output to go higher than the reference voltage on the other input, the output swings low or high stopping the device one way or another - perhaps by cutting VCC to a switching IC. It's a fairly cheap thing so I doubt it's fancy enough to have a micro in there - THAT would be a problem since the threshold might be internally programmed !
Aside from the theory, an immediate practical issue would be the capacitors (and other components along the input for that matter) since they're very likely not rated for anything more than 16v, so those would require swapping for 25v or higher ones....
That's all I can think of TBH...doesn't sound too difficult on paper, but who knows what I'm faced with once I actually pop the cover off
It's rather small in size, so I don't think it's rated for anything higher than 200w - maybe 300 pushing it...Any thoughts ? Cheers and thanks
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