Grrr ... just typed a reply when the forum crashed - I'll try again ....

We use the HRDX from Marlec - takes the 913 and 100W of solar and split charges over 2 battery banks. This means in practice once the engine battery is full you get lots of power into the domestic bank. It has a good display showing voltage of each battery bank plus amp input from 913, solar and combined.

Works very well in our experience.

I believe Marlec have just released a new regulator (HRSI?) which takes more solar input - but I'm not sure if it charges two battery banks?

Jonny