Bests & Worsts Reviews from Amazon

I teach photography to teens and have two Canon Rebels on hand for the kids to use. Because they are used often, I thought it would be wise to buy 4 of these batteries to have as backups. The charge on these batteries have been extremely disappointing. They will last an hour, at most, when in use and do not hold a charge when not in use. If I charge the battery the day before, then pack it in my gear bag, the battery will be dead the next day when needing to be used. Literally, the only way to get use out of this battery is by taking it directly off the charger and putting it in the camera. Because of the large number of positive reviews and the fact that my experience is with teenagers using the camera/battery, I initially thought I was an exception and they are still genuinely good batteries. However, I have had no issue with the Canon brand batteries the cameras came with. The most alarming issue is the battery cannot even hold a charge overnight. I cannot charge these batteries ahead of time and have them in my bag for reserve use. They will not work.