Modular Powersuits is a mod that allows the user to build a Tinker Table. This table can be used to modify and upgrade power armor, and its own power tool. While it required its own components to add the upgrades, it is free to modify them. (For example, to increase mining speed, or defense.)
Bear in mind, tinkering does come at a price. Increase your battery capacity, and you could be slowed down significantly by the weight. Increase your damage output on the tool, and you could find all of your power drained too soon.
There are numerous recipe sets for this mod, but it appears that the IC2 set of recipes are enabled. For example, to craft the armor and tool, you need refined iron and basic circuits from Industrialcraft.
For charging the armour, you can also use MJ or IC2 Energy, which makes it much cheaper/easier to charge your armour or the powertool. The Only one thing is, that the more energy you charge to the armour, the heavier you are with it and so this sometimes keeps you away flying.
For more information on the recipes as well as the mod, follow the link below.
Additionally, the current version of the mod's Tinker Table will cause lighting errors when looked at. This is the most noticeable when viewed in the inventory along with cobblestone, or if you're looking in the direction of the table, while managing your loot with Iron Chests. A newer version of the mod is also available on the developer's website that corrects this problem, and adds a few new components/Upgrades.
Take note, currently, there is no way to craft the LV Capaciter unless you update. The recipe required 2x Powersuit wiring along with an RE battery in the middle.