You can't use the $102 Eco-Worthy MPPT controller because it can't accept that 46Voc voltage input. Is more like 42v limit.
Next up in price would be a Tracer MPPT at around $140 that does have the voltage (100v) but IMO you should keep the voltage well below that to be sure. Which means put the 46v Voc panels in parallel not series. Others might say go two in series at 92Voc but pushing your luck IMO. Same with any other controller with 100Voc limit.
Next up in price is probably to near $300 but might have a few extra features. But would your mum ever use those extra features?
