In the process of changing/upgrading my power supply system for a Li-Cor gas analyzer and CSAT3B from 12 vdc to 24 vdc. The tower is 85ft tall. Plan is to power the gas analyzer and CSAT3B at 24 vdc. I'll need 12 vdc to power my CR1000x and sensors(100 ma steady, up to 350 ma while calibrating a pair of soil heat flux plates a few minutes per day). How is 12 vdc typically provided in this scenario? Tapping into the junction between the two 12 vdc batteries? I've read this isn't ideal due to the power drain being unequal/unbalanced between the two batteries. A linear voltage regulator comes to mind, though not very efficient going from 24 vdc to 12 vdc. Switching regulators do better but could create a lot of EMI (not sure if that is legit concern?).
Suggestions/comments would be appreciated.