Hi simon, I am not absolutely sure, but most Lawrence hand held VHF's are 12 volt battery
supply. and as far as I am aware the USB power is standardised at 5 volt... so there is no way you can charge direct from USB. But you may well be able to, direct from your solar panels
. The positive answer is to ask Lawrence, in the US, they are usually very helpful, compared to many of their dealers who apparently know little or nothing about the items they are selling except which one gives them the greatest commission... Happy sailing. h the boat.