All good information. Thanks for input, will start trying different things to see if I can clear up mystery.
I have been keeping updated on this thread for the past few days now. I see some information that is surely not correct and I see some that is right on target.
I will say this with out question, the quality of trail camera photos will begin to diminish as the level of battery life gets down to the one bar level.
I make that statement because I do have lots of experience with trail cameras as I have 37 of them in the woods 24/7/365 and I own a total of 62 of them. I have been keeping very detailed records on every one of my cameras over the past 7 years now. Just during 2016 and 2017, my cameras took a total of 258,007 photos. Yes, I have had some failures along the way and if the warranty had expired, I replaced that camera with a new one instead. I did have two failures under warranty back in 2012 and WGI replaced those cameras immediately. Over the years, after a cameras may have failed for whatever reason I have brought the failed camera home and took it apart somewhat and did my best to check all of the features that I could. On one camera, a woodpecker pecked a hole right through the sensor lens. That camera was salvaged and put back in service after I took out the original lens from another camera from 2 years prior and installed it and it still works fine today. Back about 4 years ago, I had one camera that had a moisture problem during the middle of the HOT summer. What I found was the fact that the interior of this camera was reaching over 100 degrees F every day and as it cooled down at night and then got back super hot the next day, the moisture would be created inside and would short out the terminals etc. I ultimately brought this camera home and took it apart as much as I could and then put white rice inside of it and closed it back up in a one-gallon ZIP-LOC bag for over a month. When I opened it back up, I took out all of the rice residue and then used an air hose blow it out and then vacuumed it too. I put it back in service and it lasted another 2 more years after I moved it to a different location. I have some cameras that have been in continuous service since late 2012 and I have an assortment of various model types that were manufactured from 2013-2017 that I bought just to try and see if I could find a better camera model for my uses.
Because I do know the exact life on all of my trail camera batteries, I decided back in 2014 to start using the DURACELL Quantum batteries in all of my AA battery cameras. I just bought my first two packages of size "C" Quantum batteries recently and I will using them in the future on certain cameras that require the size "C" cell batteries in the future. I have always used the Duracell brand because they have performed really well for me over the years. But with trail cameras, based on my records, I know first hand that the Quantum batteries last longer. I buy them from Sam's club ONLY when they are on sale. It actually saves you money in the long run.
I did my best to check my cameras most every weekend over these years. Since I ONLY use WGI cameras, their cameras are very easy to set up in the field and they have an area that shows the battery level of energy on each one of my cameras. I do check the battery levels on EVERY new battery before I even take them to the woods and ultimately change them out. I know that EVERY one of them have 1.62 Volts of energy before they go into my cameras. Since I frequently visit my cameras each week, I DO check the battery level from 4 Bars (being the maximum level down to the 1 BAR level). When any of my cameras get down to the ONE BAR level, I change it out right there in the woods. I physically write the date of this new installation on every one of these new batteries as I install them. Likewise all of the old "diminished" batteries that I am taking out already has the original date of installation. When I get back home to upload all of the photos for the week, I also check the remaining energy level of every failed battery that I have put into a "snack size" Lip-Loc bag. I catalog every detail of that information for every specific camera so that I do know the exact performance of each camera and set of batteries involved. I do recycle all of my spent batteries too (which is currently a bag that weighs 22 lbs). One other very important fact is on some cameras, when changing out memory cards, the cards are installed 180 degrees opposite (backwards) of most cameras so don't jam it in wrong and try to make it work because it will damage your memory card that way. I realize that this is not a problem for most users BUT for users with as many cameras as I use, you have to always remember just which cameras work that way.
Earlier this evening, I checked the last 21 times that I have changed out batteries on various cameras. We all have to realize that the exact battery performs different in one cameras versus another. In these last 21 change-outs, the battery life went from a high level of 16, 14, 11, 12, 10 1/2, 9, 8 1/2, down to 6, 5 1/2, 5, and 4 1/2 months depending on which camera was involved.
Most of you probably didn't realize it BUT a AA Duracell Quantum battery does have 1.62 Volts of energy to begin with and it is VERY COMMON that when I change these out at the "ONE BAR" level in various models of cameras, the remaining voltage left in the last 21 change-out times included levels from a remaining high of 1.31V down to 1.20V. The majority of the 21 readings were in the range of 1.27V down to 1.22V. Based on my experience, the Quantums do hold a charge longer than the regular "Copper-Top" batteries. I do check every new battery and also after the batteries are removed with a CEN-TECH Digital Multimeter (of which you can get free from time to time at Harbor Freight Tools). Thankfully, I have 3 of them and they work excellent for testing lots of different things. When my cameras get down to one bar of energy left, their functions are not as sharp in color/night time black and white clarity. The sensor reaction time is not as good as the batteries reach a lower levels of energy. I do believe that fact happens on most every camera brand manufactured for trail cameras.
I surely agree with rosewood's comments as you ALWAYS CUT OFF YOUR CAMERA before removing the memory cards. Otherwise, you can very easily lose your photos from the previous week. Yes, a long time ago, I learned the hard way too. I always swap out the cards from my cameras and install new ones in the woods. I bring all of them home and upload them directly onto my computer, then follow the exact procedure that he mentioned so the data on every memory card is ultimately completely deleted after it was transferred onto your hard-drive. Then you have the option to review and possibly delete OR keep any of your chosen photos. This reformatted card is then ready to be used next week as I swap the cards out again. In my case every card is identified with the exact camera location and I use the same card back and forth every week as such. Since every camera has an exact location, it has made it very easy to maintain a library of various camera photos over the past 7 years now.
In regards to failed Memory cards, I have ONLY used the Sandisk cards and 90% of them are 8 GB cards and some are 4 GB cards for low volume locations etc. In all of these years, I have ONLY had two cards to fail for whatever reason. Keep in mind that I have used these cards most every week for 7 years now as I inset them into my cameras etc, then take them out a week later, bring them home and insert them into my computer and after reformatting them, they are put back into the package to be used again the following week in the woods. I am surprised that I haven't worn them completely out in the process BUT I have been fortunate so far. I'm in the process now of buying another 40 of the 8 GB cards so that it will cover all of my cameras with plenty of spares whenever I install them in the woods. The Walmart manager ordered them for me a couple of days ago since they don't keep the 8 GB cards in stock very much.
One other thing is to realize that just because a camera is a 12MP, 14MP, 16MP, 20MP or even a 22MP doesn't make them any better overall than a 6MP, 8MP or a 10MP camera. It takes a lot of trial and error BUT you might realize that a certain camera needs to be set on the "MEDIUM" setting rather the the "HIGH" setting for maximum performance etc. Another thing that a lot of trail camera owners don't realize is the fact that a 10MP camera that you program for "High Setting" levels really is taking 10 MP photos and on the "Medium Setting", it might be taking 8 MP and on the "Low Setting", it should be 6MP photos. It works that way with most of the trail cameras when you program properly BUT it does take practice to really decide which photos are the best for your location. Based on where you decide to actually locate your camera can make the difference from 200 photos per week or maybe 10 photos per week also. Just don't get discouraged in the process.
In fact, some of the best performing cameras that I have are 6MP, 7 MP, and 10 MP cameras. THE ABSOLUTE WORSE CAMERA THAT I HAVE IS A NANO 22MP CAMERA. It is a very small camera (holds ONLY 4 AA batteries) that can be well hidden as such. I thought originally that it would be great BUT it takes up lots more memory on each card and the 6MP Blade X6 camera that sits a foot above it out-performs it every day. They are both located on the same tree over-looking the edge of my pasture. Recently, I removed the Nano 22MP camera and brought it home to use it more as security camera instead.
I hope that some of this information might be useful to other camera users. I surely don't mind sharing any of my experiences that could possibly be helpful to others.