I've used the La Crosse BC-700 and BC-1000. Both of them have heat damage to the board. Yes, I charge the batteries at the highest setting. There are only 24 hours in a day. Nonetheless, the charger should not cook the board. Both of the units now have issues with the setting buttons. The BC-1000 only charges at 100 mAh. The BC-700 mode does not work. Daily use of these units I put near a fan to help dissipate heat. Currently I've been using a Opus BT-C2000. It is a larger charger and the batteries are farther away from the circuit board. Past 8 months - so far so good.