TL;DR yes for "normal" play.
Long answer:
Are you using any mods to change the day cycle that affect the capacity like Clockwork? If so, what day multiplier are you playing with?
If not, the "Day length multiplier" in the Realistic Power settings is probably set to 1.
Basically, this mod adjusts the capacity of accumulators. If you play with normal day-night cycles then a factor of 1 would be correct, and that does lead the high capacity accumulators to have 2.44MJ of capacity. The mod should default to a factor of 205 (for 24h day-night cycles) which would equal to 500MJ capacity.
Right now it only really considers Clockwork so if you use other mods to change the day-night cycle, you'll have to manually set the multiplier in the Realistic Power settings.
