Well, for the few bucks it'll cost you to conduct the experiment, it's
probably worth a try in a pinch, and it'd be a benign experiment as well (you
won't hurt anything if it doesn't work out).

The BR1620 and CR1620 are physically identical and provide the exact same
Nominal Voltage, but they use different chemistries, tuned for different
applications. They therefore exhibit different characteristics, a key one
being Operating Temperature Ranges, with the BR series extending the high temp
limit by 20°C over CR series.

If that was all there was different, you'd be good to go, but there are more
significant differences, with the key one being Continuous Drain (BR = .03mA,
CR = .10mA) which means the BR can only provide 30% of the current of the CR
when you push the button on your key. The effects of this could range from
virtually nil to reduced range to total lack of function, depending on how
much power the key transmitter actually demands to do its job.

http://www.panasonic.com/industrial/battery/oem/chem/lith/coin1.htm

Cheers

/daytripper
'00 s4 6spd