Bug in Lapotron Crystals
I think there is a "small" Bug: If you craft a Lapotron Crystal with a charged energy crystal as ingredient, the resulting lapotron crystal will be charged, too. The energy crystal stores 100.000 EU, which gives you 900.000 EU.
Adding uses for Lapotron Crystals
In .minecraft/config/IC2.cfg you can edit that file and in general...
# Enable usage of lapotron crystals on miners enableMinerLapotron=false
Set false to true and lapotron crystals can be used in miners.