solar panel cooler party fun guidance on circuitry..

i am making a "party cooler" i want to add a fm radio and aux port and a usb charge station for atleast 3 devices one multi color time changing led and a removable flashlight white led for the inside (nothting fancy), i have 4 6x6 solar cells rated at .5v 3.5w 6.89a i also want to have the battery bank be able to be plugged in to the wall. i am having problems determining the type of battery to use in the bank (rechargable) i also want it to work for atleast 5 hours(not including device charging), (avg kegger/bonfire/beach fun). if anyone knows what i can add to this thing that would be helpfull. i was thinking of AA batts or possibly a few cell phone batts but if their is a better way.

the speakers are 3w each running 5v i havent ben able to determine the fm reciever as of now.

or a 3.0 usb charger do the volts and amps have to be specificly 4.7v 5a? or does the +- 25% still apply. if any one has any references to help with simple pcb or freeform wiring

are most portable speakers/radios rated 5v?


(was in a car accident, lost alot of brain buzz.. be nice (used to build beam bots :P) i would like to try to pick up the basics if anyone has any good refrences. circuit/ electric theory.

38 can cooler
bigger rubber wheels
will be putting the batt bank on the side under the handle.

You will need a lot more then some cell phone batteries or AA rechargeable to get 5 hours of use out of it. You need to look into a set of Sealed Lead Acid batteries with a charger so you can plug it in. You'll likely need to go with either a 12V battery or 9V battery depending on the radio you choose. Either way you will need to put together a voltage regulator to bring the power from the batteries down to the 5V you'll need for the USB. A 7805 will take anything between 7V and 35V and give you a decent 5V output. It can offer up to 1A which will be more than enough for most USB devices to charge.

The solar panels you have will not be able to support the system. You will need a solar panel that can offer a volt or 2 more then the batteries output in order to trickle charge the batteries. But most of your charging will be down at home while the system is plugged in. The solar will be more for extending the run time then being a primary means of charging.

How much power the radio needs will depend on what radio you get. It could use anywhere from 3V to 9V. If you go with a car stereo head unit then your talking 12V. If you plan to use a different set of speakers than what comes with the radio then you need to consider how much power the seeker amp will need.