Here is something about the trigger voltage
.
Canon EOS cameras are made for 6 volt. Using a flash with a higher voltage may damage the camera. It can destroy the camera immediately or slowly. I wouldn't use that funky Nissin flash if I were you.
" Note that the damage to the camera can be subtle and cumulative - simply hooking up the flash and seeing if it works is no guarantee that the high voltage isn’t slowly damaging your camera’s flash circuit - arcing and pitting connectors and breaking down internal components. (of course, Canon is probably being a bit conservative with its 6 volt limit, so you might not be taking a huge risk if the voltage of your flash unit is a tiny bit over) Note also that the power supply used by the flash is irrelevant - it has no bearing on the trigger voltage. Many Canon Speedlite flash units, for example, can use high voltage battery packs but they still have low trigger voltages. And portable battery-powered flash units may require 6 volts in battery power but nonetheless may step up the trigger voltage considerably."