8v dc to 12v dc

Check the radio specs to see its operating voltage. It might say something like 10 to 16 VDC. If that's the case, add a second battery in series to achieve 16VDC for the radio only, not the cart!Prepare your future. It wasn't the lack of stones that killed the stone age.

The problem with adding an extra series battery is that the battery won't get charged by the standard golf cart charging system. The way to go here is a DC to DC converter with a 12V output and an input range that covers 8V. A quick Google search turned up this one: http://www.powerstream.com/dc6-12.htm , and there are many other manufacturers of these.

Thanks