Car completely Dead - Battery only 6 mos old

[dan-kc]

Hi All,

Drove car fine 3 days ago. Went to start it with both keys, and absolutely nothing. Not a single light on the dash or any noise.

Charged it 24 hrs with trickle charger that has worked in past, and no change. I changed it to a full size battery charger, and have heard some intermittent clicking occasionally in engine somewhere, but still doesn't appear to fix anything (still not a light on dash or noise when key inserted).

I measured voltage at the jump terminal 3 different times, and it measured from 3.4 to to 5.1

Any suggestions on next steps or possibilities? Thanks