In the Merc BEG (Body Equipment Guide) for Upfitters...in Section 7.31 it says:
p.44 of the pdf
"Do not connect batteries with over 100aH directly to the vehicle's electrical system...snip...
...snip...If the system is already equipped with one additional battery, no more additional batteries may be connected without a charging current limitation."
I've read several posts where folks' SMBs have ~200aH (or more) connected to the Sprinter electrical system or have an electrical A/C connected to the add'l batteries running from the stock alternator....to my knowledge, SMB is not installed a B2DC charger limiting current from the stock alternator.
The reason I ask - the upfitter that did my van imitated the SMB system - >
2 x 224ah 6V batteries in series connected to the stock alternator via relay/contactor that closes when the engine is running - this is used to run a 3kW inverter + Dometic 12kBTU roof AC).
Per the BEG, this is not permitted. Overloading an alternator leads to low system voltage and premature failure.
What am I missing?