Randy has two choices of replacement using PowerMax. One is to just replace the lower portion with the 55amper or you can replace the whole power centre but that one has a 60amper in it. In any case the WFCO may be ok in your use in your RV so IMO wait and try it before tossing it already.
Your solar may be ok for maintaining the batt(s) at home even at 100F. It is only "on" half the 24hrs of course, so it may be more "gentle" on the batts even if the Float voltage is a tad high for 100F. You could wait and see on that too.