I might be wrong and using the Charger the wrong way, but I tried hooking it up with every power source (RF, Tesla, IF etc) and it does not want to work... Any ideas? Could this be a bug?

i just tested the charger with a TE energy cell and TD leadstone conduits and it appeared to be working, at least the charger produced the particles that indicates it's sending power. Did you happen to look at those power items specifically?

i have further tested this in a mod pack and charging was working for me, again with TE power.

Yeah, the charger does not work with immersive engineering power, rftools power or integrated dynamics power, seems it's a compatibility bug. I took some pics in case I'm doing it wrong

https://imgur.com/a/x04Qu

merged Mallrat PR, ready for release testing

As a quick test I made an instance with the following mods

JEI,
The One Probe,
Immersive Engineering,
RFTools,
Integrated Dynamics and Integrated Tunnels
Cyberware built from local

I included JEI and The One Probe for ease of accessing the items, they shouldn't affect anything. TOP will also show RF/Energy content of the Charger, so that's a bonus

As built, all three mods, IE, RFTools, and Integrated Dynamics are providing power to the Chargers.

https://gfycat.com/PopularVapidGuernseycow

Ah, the common element here is those mods don't use RF. They use Forge's Energy stuff. Implementing RF is 99% of Forge Energy, so it may be missing a capability

Can I configure it to use redstone?

@WasdCat can you make a separate feature issue? since i am going to close this one. thanks