I use the Accu Chek Aviva and the battery gives NO warning when it gives out-- no blinking, no anything-- it just dies! The first time time it died it was at a LATE pm shot and the meter wouldn't come on, no warning or anything. So, I had to make a trip to Walmart to try and get a battery-- they were out of! So, I left and went to a 24 hour drugstore and tried to purchase a battery-- they were out too! So, back to Walmart I went and I just purchased a new meter, since it came with a battery!
My advice-- get a spare battery and keep on hand at all times! In fact, I keep two batteries on hand! Lesson Learned!
Good Luck!