I would get the temperature compensated charge controller, the Renology has. It's about $49, the least expensive and it the voltage settings can be altered by the user. Personally I'm going pay a bit more and order the Morningstar Sun Saver Duo. A temperature sensor will let the CC know to adjust the voltage as the battery temperature changes during the seasons. The difference is an increase in voltage is about .017v for every 1 degree decrease in temperature. The increase in voltage, should the temp drop from 80F to 50F (a 30 degree change), is about 1/2 volt, and the increase in voltage needed to charge the batteries fully or at all if the temp drop is from 80F to 20F, is 1 volt. Unless the battery and charge controller are kept inside where the interior temperature is relative stable and around 70F or higher, there is real need for a temperature sensor on your CC. The batteries will have more power to deliver and will last longer.