Geektastic:

 

MackinNZ:

 

What about a ruggedized phone like one of these for example?

 

https://catshop.co.nz/phones/cat-s41-phone-black.html

 

 

 

 

"and a non-removable 5000mAh Li-Ion battery with an outstanding 38h talk time and up to 44 days on stand-by."

 

 

 

Wow. Maybe I would get one just for that!!

 

 

I have a Ulefone Armor 3W. 10000mAh. It's a massive tank but not having to charge is god damn amazing. This brand may also be applicable to the OP>

 

https://www.ulefone.com/armor-3w.html