I do not use the batteries for my "MacTronic LED bike lights BPM 170 lumens". Unlike cheap batteries the batteries (charger Technoline BC at least lt. 700 Battery Charger black) keep the full voltage of 1.5V relatively long, the voltage breaks but a rather fast. At current temperatures of -10 - -15 ° C, the voltage stops, however, only about 40 minutes - after being advertised with function down to -20 ° C, I would have actually been more expected. Nevertheless, I am actually very happy - so cold it's not so often a year.