Most stores recommend a Group 35 battery for the Mirage (490 cca). Here is how it fits (No modification required). I inserted an Amazon padded envelope in the side to show you how much extra space is left over.
But I discovered at Walmart you could get a Group 24F battery for the same price ($49) and it has 585 cca (better than only 490 cca of the Group 35)
As you can see the Group 24F battery is significantly larger in size. We can make this work but it will require you to chop the plastic box that the battery sits inside of. We call that plastic box the heat-shield because it buffers some of the extreme heat away from the battery. It also has holes and grooves on the bottom to allow any battery acid to drain down.
See this thread here for more pictures of what the original box looks like:
https://mirageforum.com/forum/showth...ll=1#post82144
We will chop the plastic box using the Harbor Freight Oscillating multifunction power tool with a wood blade. First I will flip the box over and chop off the devil horns underneath because it is the only way that the box will fit. Use some clamps to clamp the plastic box down to a table.
Next we will make the following 4 cuts on the side:
Here is the finished product:
I was planning to use some JB Weld to glue the plastic box down to the metal platform but I discovered this is redundant and unnecessary because the metal top clamp exerts enough friction to keep the battery from sliding around.
Job done. This larger battery (which costs the exact same price and has same warranty) is a better value. The higher cca mean that the battery will last longer and this would be great especially for Uber drivers or people that have an upgraded sound system or people that use alot of electronic gadgets in their car.
I hope this has been helpful. Dont forget to add some Vaseline or the battery-terminal-grease to keep the terminals safe from rust and corrosion in the future.