I am hoping someone can offer some advice on changing a sinewaboard from 48v to 96v. I have a 96 volt battery bank. There are pure sine wave inverter boards readily available on ebay and aliexpress.
Unfortunately though, 96v stuff is not very common. the boards they offer can be made to work with 12v, 24v, 36v and 60v. This is achieved by changing one resistor on the board and of course using an appropriate transformer. The 60v option has a maximum input dc voltage of 72 volts. As far as I can tell; the limitation here is the voltage parameters of the FETS. They are designed for max 80v. My question: Would it be possible to change the mosfets and gate resistors to carry higher voltage as well as the capacitors of course? My understanding is that the driver board requires a given voltage to work and does not care as long as it's driving the Mosfets. The feedback will come from the 240v side so things should work. I do not know how the protections would work though. Under voltage, over voltage, max current etc.

https://www.aliexpress.com/item/Free...b83d16af&tpp=1

 

Welcome to AAC!
Without a schematic of the board in question we can't be sure what other components would need to be changed to suit the higher supply voltage .

 

My question: Would it be possible to change the mosfets and gate resistors to carry higher voltage as well as the capacitors of course? My understanding is that the driver board requires a given voltage to work and does not care as long as it's driving the Mosfets. The feedback will come from the 240v side so things should work. I do not know how the protections would work though. Under voltage, over voltage, max current etc.

Yes if you replaced all the DC power handling components with ones rated for double the stock units voltages plus changed the necessary other components out relating to any other DC side voltage and current sensing it could be done.

 

This can be done even by observing the following:
0. Change the main transformer to 40V instead of 24-26V that the system is using now
1. change all the mosfets to at least 300V mosfets. higher ones are better.
2. Change all the DC surge capacitors to a value higher than your operating voltage by at least 30V minimum. 96V system, use 150V or higher.
3. on the main control board, there will be a 12V source and a 5V source if the system uses micro-controller. Remove those regulators or disconnect the power line to those source.
4. now get a buck converter to step down the 96V to 12V.
5. Now connect the 12V to the 12V point you disconnected
6. Produce 5V from the 12V generated by using the 5V regulator you removed. Connect the output to the 5V point you disconnected.
7. remove the transformer from the heat sinks and connect your voltmeter in AC range( AC 200V or higher but not too high) now on the inverter with the transformer removed and the meter connected. The meter should read 80V AC or higher meaning the system has worked out.

Read my blog on inverters

THESE ARE MINOR PROBLEMS AFTER

1. you cant charge using same system
2. low battery alarm will not work
3. low battery shutdown will not work
But the inverter will work correctly.

@opanin17
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