Options were to keep my maggot box switch that manually connected the leisure and starter while charging (never going to do this despite the ingenuity it looked crap and I'd forgotten to disconnect the starter from the leisure bank a couple of times and this could be my undoing by draining down the starter so I could not start the engine to charge the leisure bank)
So as the units were out of any warranty I paid up the £100 plus vat for a new Smartgauge and Smartbank -the relay being tested ok. Daft you cannot buy the Smartbank as individual items - you have to buy the full set including the relay !!
I have to assume I buggered it up when re wiring the battery bank here .... so an expensive lesson learnt. It has taken me to now to reinstall the supplied parts and I have been living back on board for about three weeks - relying on the MTTP controller that shows three states of charge for the batteries good, needs charging and 'o' dear ! I got down to needs charging but no idea what state of charge other than I needed to run the engine.
So I conclude I need the Smartgauge and the Smartbank to keep my batteries charged as they should be and to tell me when to charge. I am one of those that the canal forums refer to as a serial Smartgauge watcher.... but the the batteries are an essential for the boat and comfortable living.
Knowledge is power so they say...!!
The relay back in place replaces to maggot box and manual switch that I forgot to switch off the connection between the leisure bank and the starter..... risky
My temp lashup ....
I celebrated by leaving the engine charging while emptying the cassette in the last light of a deserted Fradley junction. The smartgauge needs a few cycles of charge/discharge to establish the current state of charge of the battery bank, it is a fit and forget system, only I'll be checking the %'s as is my habit.