Hi Steve, with a CTek M5 charger on the basic setting you will not harm anything on your car. The charger will not allow it, but it will also charge your battery and it is designed if necessary to be left permanently on the battery, on the vehicle. I leave mine on all the time, and after an extended holiday I used it on my wife’s Jazz, which is actually an AGM, but I wasn’t sure, so just used the basic setting. All totally fine. Obviously if you now know it is an AGM, it makes sense to use that setting on the charger. Good luck, cheers, Roger