Found time to trawl for original post 
@Qmick - this was initial test build, since refined with decent set up and wiring and replicated multiple times since
@tobiaslinkwitz note use of VE Solar controller Used several now: very good - but have avoided complications around VE connect bus etc…just use as controller/charger. Sadly this very unit (since used in another field deployed rig) finally died a few weeks back - not investigated why, just swapped out, or looked at any warranty…should just still be covered I hope! (They ain’t cheap! 
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