Hi,
After my recent major investment in (lead-acid gel) batteries, and given that we are at about the hottest part of the year here in sunny London (~25C today), I finally got my act together and bought and installed a Morningstar remote temperature sensor to go with my MPPT controller.
I'm kinda hoping that I won't see any difference in the voltage graph with the RTS connected, and that having the charger [with in-built temperature sensor] about 2' above the batteries was 'good enough', but using the RTS seems a prudent insurance policy.
Rgds
Damon
[Edited for clarity]