The LapPack is a piece of armor added by Industrial Craft 2. It's worn in the Torso slot of the inventory, and has the ability to recharge the currently held tool. It is an upgraded version of the BatPack, and can hold five times the amount of EU as one, up to 300,000 EU.
All of the tools that can be recharged with the BatPack can be recharged with the LapPack. In addition, the LapPack can recharge the Mining Laser, the Nano Saber, the OD Scanner, and the OV Scanner, tools that the BatPack cannot recharge.
A charged LapPack can be placed in Medium or High Voltage machines or EU storage devices, but not Low Voltage machines or the BatBox, to power them. If one wishes to power a Low Voltage machine with a LapPack, a Transformer Upgrade is required.
Similarly, only Medium or High Voltage Generators, the MV Charging Bench, the HV Charging Bench, MFE, and MFSU can be used to charge the LapPack. In addition to these charging methods, wearing the Solar Helmet, the MV Solar Hat, or the HV Solar Hat will recharge the LapPack passively, so long as the player is within view of the sky. The Static Boots will also charge a LapPack when worn.