I'm currently rank 21, and as soon as I'm done with 2600 hacks (140 to go!) I'm going to start ranking. I've been saving every energy cube and tri-matrix emblem I get from the daily rewards and have a total of 30 so far. I know using them now to refill my 230 max energy is a waste. Is there a general consensus on the amount of max energy I need to have to not be wasting the refill artifacts?

Technically speaking any rank is a good rank to use energy refills. But to get the most out of it you must continually upgrade your max energy.

Logically having a higher energy will provide a better effect. On the forums there is a formula for autoranking but I forget where it is.

It's up to you to decide when you want to use your energy refills and how high you want your energy to be.

But to answer your question anywhere over 2k is a good time to use refills. Considering your rank I think your max energy should be 12 times your rank (I believe).

10x your rank in energy and a strong attack to autorank off of NPCs, Play. 15x+ to autorank off of missions, depending on missions (can take as much as 22x). PvP, I believe it's around 14-15x your rank to autorank, assuming you win a lot.

I did not know about the auto-ranking formulas. Thanks for the replies.