[Elecraft] K1 Reverse Polarity protection/battery fusing?

[ARDUJENSKI at aol.com]

For  about a year I have been operating my K1 strictly battery power.  I 
have a barrel connector attached to a pair of red/black wires with red/black  
alligator clips to connect to the battery. As my eyesight is getting poor  I 
do not want to take the remote chance I can apply reverse polarity.
 
The manual (Section 11 OPERATION, Connections, Power Supply) only  states 
to install a 2 amp fuse but not sure if this is the best method
 
I would appreciate recommendations as to whether the 2 amp fuse will  
suffice or if some sort of diode should be added
 
Thank you
 
Alan KB7MBI