1 voltage meter for both solar panel and battery

[deannos]

Well in that case you just need a change over switch. Connect the yellow wire to the common and the battery +ve to one of the other contacts and the solar to the other contact. See thishttps://learn.sparkfun.com/tutorials...pen-and-closed you can get a small switch for Maplin ..Clive

Ok, thanks for your help. So i need a SPDT and switch the common, is that correct