Good day, what would be the need to feed it with 28v and not with the 24v that the original source brings?
Although I'm pretty sure it supports up to 30v because I saw it somewhere and this web page confirms it. I'm looking for success without official documentation to avoid burning anything.
you can also place some diodes of 4a in series to lower the voltage from 28 to 24v .. each one reduces by 0.7v so you should place up to 6 diodes in series .. something totally untidy, but I do not see why it does not go to function.
tell me the need for those 28 and I will try to help you better.