Refer fans for improved cooling...what are the best options?

On my Class A I used one of the solar powered fan units from any RV supply house with a battery operated inside the unit. After these mods I was able to decrease the temp setting by 1-1.5 numbers on the display and it did not matter whether the reefer was on the sunny or shady side of the RV. Solar; no muss, no fuss. This performance improvement was monitored during a 9 month trip and I never worried about reefer performance again. Do not over think this. RV reefers have been installed loose since their inception.