I have a Kenwood HT with the optional BT-13 AA battery holder. It says "do not use rechargable batteries" on the unit. Why not? Will the voltage be too low? Will it simply reduce the output of the unit or will it do something worse? I am well stocked with Sanyo Eneloops. Why don't they make an 8 AA battery holder that would produce 10 to 12 volts instead of this 4 battery holder than produces only 5 or 6? And for the price, they could include a years worth of AA's.