The black and red wires are out put wires that go to the battery red being positive and black being negitive
Now as far as power going to this there must be another place to hook up a power cord
Look red and black coming from the charger usually mean pos and neg to the battery not incoming power
Is this charger 220 volt input ?
Power in does not connect to these out going leads
There must be a small panel in the back that can be removed for the power going in