0electropeppersBest Answer 8 years ago ReplyUpvoteAs steve said: it's depending on the power, which the solar cell will generate. You should look into the data sheet of the cell, how much current it generates. Then you have to check, how much current your radio will consume.If the generated current is lower than the needed current you can put more then one solar cells in parallel (connect all +-terminals togehter and do the same with the negative terminals). The number of needed panels can be easily calculated: needed current / generated current = number of pannels If you don't know how much current your radio will consume make a measurement with a multimeter. If you do not know how to do this, you could also take a raw guess: 1. take a fresh battery and put in in the radio. 2. turn the radio on as you would usually do. 3. measure the time your radio is running (in hours)4. look on the emptied battery, there should be a value with the unit Ah (ampere-hours).5. divide this value by your measured hours and you will get the rough current-consumption of your device in Ampere.Hope this could help you.