depending on motorhome convertor could be as late as 2020. Mercs had them from 2015. You dont need one for a b2b to be usefull. Remember if you have a split charge relay system you need to disable it when fitting a b2b2.No it isn't
Can't remember whedn Smart Alternators first appeared on Ducatos but it was certainly after 2010
It looks like you have a well-established system) If your system can handle the flow of energy and has been working perfectly for almost three years, then perhaps you don’t need a big b2b.I've never had a b2b or solar panel so can't say how good they are.
My X2/50 (150a stahdard alternator) had a parallel connection between the main battery and the 2x100ah standard Lead Acid secondary batteries through a voltage sensing relay. But that would be no good with a smart alternator.
So my X2/90 (180a smart alternator) has a parallel connection between the main battery and the 4x100ah standard Lead Acid secondary batteries through a simple 200a relay control;ed by the ignition switch (can just get 2x019 100ah batteries under each X2/50 or X2/90 seat)
Both using hefty 25mm2 cable. I have a dashboard switch to disconnect the relay connecting the secondary batteries if ever they became so flat as to impede the main battery from starting the engine. But it has never happened yet.
It works fine and has been doing so for nearly 3 years. Takes my 510ah battery bank up to 15 volts with regenerative braking. Would need a huge b2b to handle that current? and it wouldn't provide all that free electricity from regenerative braking. Which is better for my pocket and the environment than a b2b.
But I can see neither system is perfect.