As others noted the vast majority of battery powered cameras are consumer grade. Which anyone can purchase from Amazon that’s spans $35 ~ xxx.xxx
There isn’t any money to be had in this field unless you specialize like any other industry.
As such there are lots of agricultural, commercial, and government opportunities that want & need a wireless solution. This is where the gravy starts to drip and the heavens open up!

Providing several tiers of solar, WiFi, cellular units that are mobile and offer long renewable operations has value for those with that need.
There are a few commercial packages already on the market by the likes of road sign makers etc.
Going with a all in one solution has lots of benefits as the components have been tested to provide X runtime with Y features. Nothing wrong having one of these as a customer option that can be ordered with a long lead time but offers very little profit / mark up.
A good balance is to offer a similar unit that you build using parts that offer more value which can be scaled to provide better performance, features, runtime.
If you randomly select any commercial solution and look inside the entire system isn’t very complicated. Yet don’t be fooled into thinking there wasn’t actual science, math, electrical theory involved to build the unit!
Some of the biggest reasons for failures is NOT using outdoor rated hardware. I mean that sounds so basic and simple! Yet everyday people will pick a camera, switch, POE injector, etc that isn’t outdoor rated to be exposed to extreme heat, moisture, and rain.
The hardest part is downsizing everything where it’s module, easy to install, deploy, and maintain. Every single item plays a role as to how it impacts the next. Bought a 6 port switch instead of a 4?!? Whelps that means you just spent more money on a larger IP rated box!
Installed a 25 watt solar panel instead of a 50 ~ 100 watt panel?!? Well, you’ll need to compensate for the lack of solar generation by using you guessed it a more expensive battery or more of them wired in parallel!
Decided to run a 12 volt system instead of a 24 / 48. Well you better accept you’ll be on site losing money replacing batteries. As seen above every component, wire, fuse, location impacts how the system performs. You’ll note we haven’t even talked about the method to communicate yet?!?
The vast majority use cellular as such these systems increases your / customers costs forever. But if it’s marketed right the long term costs vs reliability of connectivity makes sense for some. Where as a PTP solution strikes a good balance of initial cost but none later but assumes everything that has to do with the network is solid to provide reliable access and streaming.
If you’re weak in networking you better start cramming now to learn the basics.
At the end of the day this isn’t rocket science but does require common sense with respect to math, science, basic understanding of ohms law, electrical handling, networking, and a good working brain!
Good Luck . . .

