Reading some other posts I learned of the GT options, but 50 J to 1 EU is crazy, and for the exponential costs, no, 10 J to 1 EU sounds good to me, and what is this about breaking BackTools...
The mod doesn't break BackTools actually. But Backtools apparently doesn't work with one of the required APIs for this mod. And 50eu to 1 joule isn't that bad compared to 180 eu to one joule. But the current standard for IC2 to UE power as set by Calcavica is 500 watts/joules to one EU. Keep in mind the base unit of energy with UE is a joule. 1000 joules is a kilojoule. 1000000 joules is a millijoule. I actually support the 500 watts/joules to one EU, because otherwise converting to UE from EU is pointless in this mod considering how many Joules it takes to charge this suit.
Best choice for the conversion ratio however, is configurable. Depending on who you listen to, the ratios are very different. PowerCrystals has it at a 1800 EU to 10 UE something(I have to check, actually), which depending on how one looks at it(and if it's MJ or KJ or even J you get), it could be very powerful or very weak. But his mod is configurable, so one could make it any number you wanted. And in modding, the end user always knows his install best, and thus adding the ability to chose your energy ratios is important for people who want to tweak their install.