Looking for a good mod that will allow me to generate lots of non solar electricity.

[Dune Manta]

I'm making an all electric/xenon weapons satellite using the sunbeam lazor and the lazor systems, but all my prototypes run out of charge while performing maneuvers on the dark side of Kerbin. Since the xenon engines don't produce a lot of acceleration I need the constant ability to run my engines on the dark side when solar power is unavailable. Packing enough batteries is highly impractical as this adds enormous amounts of weight to the craft making it difficult to lift. I need a non-overpowered option to supply at least a fair amount of electricity in a somewhat compact package. It doesn't need to supply enough power to run the engines all night, just enough to keep the batteries from running out while it runs.

Anybody know a good mod for this? Please not totally overpowered parts, I want it to be at least mostly realistic.

[Ralathon]

You could try the Near Future Propulsion Pack. Among other things it adds 3 sizes of nuclear reactor (probe to 2.5m) with accompanying heat fins. It also adds capacitator banks, they have much higher charge/mass rating but charging takes a lot of time and you have to discharge them in 1 go (Good for bursts, not so good for long continuous burns).

[Dwight_js]

You can also check out the Interstellar mod. Has a few different types of reactors and generators.