I don't think the original Kenwood batteries have contacts for a drop in 
charger, mine does not anyhow.  The new ones come with lithium ion which 
is a much better battery.  I finally bought a replacement for mine a 
couple years ago, but didn't go with the ion as it takes a different 
charger.  I haven't actually seen their new replacement for the thd7a, but 
am told it isn't as accessible.  My feeling with the f6 is, if it isn't 
broke, don't fix it.  It is a good rugged radio.  Not sure what they'd add 
or imrove.  I have 2 or 3 or the chineese uv5-r radios and they are fun 
and a throw away radio, but really not a fair comparison to the f6, it is 
just in a different class.  I like the cheap ones for what they are, but 
would never get rid of my kenwood, and if it died, I'd buy another.
73
Butch
WA0VJR
Node 3148
Wallace, ks.