'98 Accord stalls while driving

Hi everyone,

My 1998 Honda Accord Coupe EX, 162,000 miles stalled at highway speeds the other night. When it cut out all power went down for a moment before the dash lights returned. The RPM and speedometer dial went down to zero before bouncing back up.

I coasted to the shoulder and tried to re-start. The car tried to turn over but quickly reduced to just a clicking sound of the battery and was completely dead.

The mechanic thinks it's the battery because it tested "BAD".

SIZE - 640 CCA
Available Amps - 338 CCA
%Capacity - 52%
Temp - 70F
Initial Volts - 12.72 Volts
Final Volts - 10.56 Volts
Impedance - 9.44 Ohms

Is this test the current state of the battery? Could it test "BAD", but be a "GOOD" battery if the alternator hasn't been working properly to charge it? I am also wondering if it might be the ignition coil.

I exchanged the battery @ Costco, but last night it hesitated again, but didn't stall. For some reason I don't think it's the battery. My guess is the alternator, but it passed the test or the ignition coil.

Thanks in advance!

Stephon