Background: I'm considering a boat setup where an Orion-TR non-isolated would charge a Lithium house battery from the lead/acid starter battery (standard setup, per Victron docs). The house battery is also charged by an Victron MPPT Controller/solar panels. I would like the solar/mppt to charge my starter battery in an emergency. I think I can achieve this by (a) disconnecting the Lion House batt and (2) setting my 1-2-both connector to "both". These two steps together would connect the MPPT to the starter battery and isolate the house battery, giving the starter battery the full solar charge.
This emergency setup would leave my Orion in-line and out-line both connected to the same battery terminal (the starter battery positive). Is this safe to do? The manual says that all models are short circuit proof, so I'm thinking yes, but I'm not sure this situation is actually a short circuit.