Nipped out to check voltages
Starter Battery 1: 90AH 700CCA unit (2-3yrs old)
AUX Battery 2: 96AH 900CCA unit (new) Numax CXV27MF Sealed Leisure battery (Deep-cycle & Starting)
Before starting engine,
Starter Battery 1 = 12.5v
AUX Battery 2 = 12.81v
Start Engine, both batterys linked in about 4 seconds when the relay activated.
Both now record 14.31v being fed by alternator
Switch engine off, check both batterys = 12.83v (they are linked)
had car door open etc, so voltage was dropping slowly.
After 6 mins they were still connected, voltage now 12.7v
came back just after 10mins and the relay had disconnected them (which is according with Profile 0 (default) i..e disconnect after 10mins if voltage between 12.4v and 12.8v,
I imagine it was delayed by moment, because voltage was 12.83v on engine shutdown, which is slightly higher than the 12.8v stay-connected permanently of the system (all profiles but profile1(12.75v), if voltage more than 12.8v the relayed remains closed).
now
Starter Battery 1 = 12.63v
AUX Battery 2 = 12.73v
So after all that waffle...
I don't like the fact that the AUX Battery 2 is draining into the Starter Battery 1 for 10 mins after engine shutdown, as long term not so good for the battery.
I think profile 2 will be best for my system.
It should link the batterys quite quickly after starting, 6 seconds after 13.2v
and disconnect in 30secs when voltage drops into 10.5-12.8v range.
will get a red and a green LED later on today, and wire that up at some point to the micro-switch.