Old PowerUp panel compatability?

My vote is for the Xantrex C35 charge controller. (full disclosure: I own and use one)  It will wire up as 12 or 24 volt, will handle all the current (above what you specify).  The options for this meter include a temp sensor and production meter (cumulative resetable amp hour counter) both of which can be bought anytime.  The meter can be remote mounted or front panel on "the box".  You can also hook up this controller for a diversion load (once batteries are charged then apply power elsewhere) like a 12v water heater element for your electric water heater or 12v fan for cooling.

All this for less then $100 bucks.  (Sensors and meter sold seperately)