Thanks jfulps for doing some testing and sharing the readings you are like the first yxz rider making history on what we have to work with on the stock electrical system.
We now know jfulps is dropping to 12.3v at times he has ran out of amps to maintain his loads at times plus all the electronic will be working at a lower voltage specs than preferred under these conditions but his voltage would go back to 13.0 volts at times when most likely his electric power steering load was reduced.
Some yxz riders if they have added a 20 amp load like we think jfulps has ( not been able to test jfulps to the exact spec's ) they can get to a no starting condition it all depends on the loads and how much you are using the electric power steering when turning under a load = more amps demand plus having the diff lock on will also add to the load plus the amount cooling fan needs run and how many times you restart the motor.
Now you can go to dual battery setup to add more amp hours and this will help but just remember both battery's will run out of amp hours it just depends on the load and how long a person needs to ride under these conditions plus it will take longer to recharge both battery's to 100%
Now if you wanted to save the starting battery so you don't get stuck with a none working starting battery I would recommend to use a automatic charging relay with this setup to protect your starting battery it will disconnect if the voltage drops to 12.7 volts and reconnect when voltage returns to 13.0+ volts.
The best news is we have some amps to work with

now it would be better to lower the load like a smaller watt led light bar and one whip if this will work for your ridding conditions.
Tips: when you get home charge your battery back up to 100% if they are below 12.7 volts or get a battery maintainer to keep your battery at peak condition.
I hope this helps my pals on yxz talk
