So I've finally got round to sorting the solar on our 57ft narrowboat and installed a Victron SmartSolar MPPT 100/30 feeding into a 200Ah AGM leisure bank. We've also got the original Beta 43 engine with its standard 70A alternator doing the heavy lifting when we're cruising. On a decent sunny day the MPPT is pushing out 18–22A from two 200W panels mounted on the roof, which is lovely.
The problem is when I start the engine while the MPPT is already in bulk or absorption — the two seem to fight each other a bit. The battery voltage spikes briefly and I'm not 100% sure the MPPT is backing off quickly enough. I've got the SmartSolar set to AGM preset (14.7V absorption, 13.8V float) and I haven't touched the alternator settings because, well, it's a Beta and they're not exactly adjustable without a proper regulator upgrade.
Has anyone fitted a Wakespeed WS500 or similar smart regulator to a Beta to get the two sources playing nicely? I've seen a few threads about it on canal forums but most seem to be American kit with lithium installs. Wondering if there's a simpler fix — maybe just a Victron battery protect or tweaking the MPPT charge profile — before I go down the rabbit hole of a full alternator regulator swap.