To jump start a dead engine battery, the connecting bus wire going from the house battery to the starting battery needs to be a large enough to pack the necessary amps. SMB typically sized this wire much smaller for the lower amp charging the alternator puts out. So unless you upgrade the bus, it can lead to melting the wire especially during a long crank.
A couple thoughts:
Why not just carry one of those jump start lithium battery units? At least with those, they hold they're own charge. Another issue is if you kill the starting battery by morning, the chances are your house battery would be somewhat low as well. These jump starters such as the antigravity battery jump packs do work well. Even the large ones are compact for storage.
If you have solar, I say to get rid of the one way isolator and replace it with a bidirectional separator such as a Blue Sea 7622 but kind of expensive and you still have to deal with high amp cranks. But with solar, you just sit around for a few hours as the battery charges. A bypass switch could be used to jump around the isolator but not a preferred method IMO.
Do you have an inverter? You could get a large enough inverter to power a small automotive low amp charger and use that with an extension cord to charge up the starting battery.
I have a large inverter and I always carry one of those 2/10/50 amp chargers, mainly to jump start others (I don't want their problem to become mine) but it could be used to charge your own vehicle I guess.
I forgot about these. Slow but might do in a pinch. Most of us have 12 volt outlets powered off the house battery.