Any idea how the alpha codes on batteries work?

The 5 character code on the batteries, 3 digits, and 2 letters, tells both the date, and where it came from. The date, what most of us worry about, is simply first digit year, second and third are the week. Hence, 901 would be the first week in 1999. Batteries normally show their age after 10 years, so they see no need to have more than just a single digit.

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On Motorola portables is there a way to determine the date of manufacture?

Look at the serial number scheme and take the FIFTH character for the year and the SIXTH character is the month.

FIFTH character	is the year		SIXTH character	is the month
s	1992		a/b	January
t	1993		c/d	February
u	1994		e/f	March
v	1995		g/h	April
w	1996		j/k	May
x	1997		l/m	June
y	1998		n/p	July
z	1999		q/r	August
			s/t	September
			u/v	October
			w/x	November
			y/z	December

Note that like cars, they do not us the letters O and I to distinguish from 0 and 1.

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