Hello all! First time poster and I'm not a mechanic so I hope you can all bear with me! I appreciate anyone who can point me in the right direction of what to do!! 
I've owned this car since brand new.
Now, replacing dead battery with a new one by myself for the first time. Should be simple enough to do myself. It's been replaced at least twice before by battery mechanic ppl.
2 issues:
1. Battery Box
there's no Battery Box at all. IS THIS NORMAL? I can't find any info about NOT having a battery box. Did a previous mechanic take it and sell for parts? I am confused about this... replacement seems expensive to me for what it is, and considering it was running fine without one. Do I need a BBox?
2. Battery Tray
I was tightening the Battery Clamp over the new batt, when the plastic the clamps hold onto snapped on one side. Couldn't believe it was plastic and not metal!
Then I realised that the other side was also partially broken from another time, and that's the reason it took so long for me to get the clamp to line up straight and not be on a diagonal.
I bought a universal battery tray , but quickly realised the only way to fit it would be to install it over the existing BT. To do that I would probably need to cut the plastic sides off the existing BT and get longer bolts to attach it. This is possibly still an option but I am loathe to try and cut the BT plastic sides while it's still installed in the engine bay.
Currently, I am having trouble removing the BT as I have gone through the service & repair manual (Mazda CX-5 Service & Repair Manual - Battery Removal/Installation [Skyactiv G 2.0] - Battery) and following instructions at the "Battery Tray and PCM Component Removal Note" . was hoping I could remove the BT without having to "Remove the air cleaner, air hose and fresh air duct component.."
I tried to get to the bolts from Step 5 onward to see if I could try and slip the BT out but I can't access smaller bolts at the bottom end of the BT due to the PCM component being in the way.
Then I would need to find a Mazda BT part which I am having trouble finding!
but if I could remove the BT then I could at least cut the sides off to get the universal BT to fit .
Does anyone have any suggestions or can point me how to remove BT?
Also is there a difference between the KE and KF BT? I found a KF BT online but I cannot find any dimensions and searches are not giving me correct information.
Any advice appreciated.
If you want photos to see what I am talking about let me know! I'll see if I can at least get a pic of the clamp part that's broken up now.
Thanks !

I've owned this car since brand new.
Now, replacing dead battery with a new one by myself for the first time. Should be simple enough to do myself. It's been replaced at least twice before by battery mechanic ppl.
2 issues:
1. Battery Box
there's no Battery Box at all. IS THIS NORMAL? I can't find any info about NOT having a battery box. Did a previous mechanic take it and sell for parts? I am confused about this... replacement seems expensive to me for what it is, and considering it was running fine without one. Do I need a BBox?
2. Battery Tray
I was tightening the Battery Clamp over the new batt, when the plastic the clamps hold onto snapped on one side. Couldn't believe it was plastic and not metal!
Then I realised that the other side was also partially broken from another time, and that's the reason it took so long for me to get the clamp to line up straight and not be on a diagonal.
I bought a universal battery tray , but quickly realised the only way to fit it would be to install it over the existing BT. To do that I would probably need to cut the plastic sides off the existing BT and get longer bolts to attach it. This is possibly still an option but I am loathe to try and cut the BT plastic sides while it's still installed in the engine bay.
Currently, I am having trouble removing the BT as I have gone through the service & repair manual (Mazda CX-5 Service & Repair Manual - Battery Removal/Installation [Skyactiv G 2.0] - Battery) and following instructions at the "Battery Tray and PCM Component Removal Note" . was hoping I could remove the BT without having to "Remove the air cleaner, air hose and fresh air duct component.."
I tried to get to the bolts from Step 5 onward to see if I could try and slip the BT out but I can't access smaller bolts at the bottom end of the BT due to the PCM component being in the way.
Then I would need to find a Mazda BT part which I am having trouble finding!
but if I could remove the BT then I could at least cut the sides off to get the universal BT to fit .
Does anyone have any suggestions or can point me how to remove BT?
Also is there a difference between the KE and KF BT? I found a KF BT online but I cannot find any dimensions and searches are not giving me correct information.
Any advice appreciated.
If you want photos to see what I am talking about let me know! I'll see if I can at least get a pic of the clamp part that's broken up now.
Thanks !