... charge mode,conversion efficiency up to 99%,can save 30%~60% of the power than traditional controller. 2.With high efficient ... ,fan speed rate regulated by temperature,when inner temperature is too low,fan ran slowly or stop;when controller stop working ... brief,technical documents,product manual etc . MPPT Solar Charge Controller 60 Amps at 12V or 24V or 48V--- 99% EFFICIENT