Validation de ma configuration

Been putting together a similar Victron ESS setup on my narrowboat and wondering if anyone can sanity-check my thinking before I commit.

Currently running a SmartSolar MPPT 250/100 feeding into a Multiplus-II 48/3000, with a Cerbo GX holding it all together. Battery bank is Fogstar Drift 48V 200Ah — decent cells, reasonable price point for the UK market.

The plan is to add a second MPPT down the line (probably the RS450/100 when the budget allows) as I'm hoping to bolt more panels onto the roof. The Lynx Distributor setup makes a lot of sense for busbar management — cleaner than my current rats nest of cables if I'm being honest.

Few things I'm uncertain about though:

• When you're running parallel MPPTs through a Lynx setup, does VRM handle the combined yield reporting cleanly, or do you end up with gaps in the data?
• Anyone else found that the RS450 series runs noticeably hotter than the older SmartSolar units? Space is tight on the boat and thermal management is a genuine concern.
• Is it worth pre-running cable for the second MPPT now even if I won't use it for 6-12 months? Feels like obvious advice but the routing on a narrowboat is genuinely awkward.

The ESS logic on the Multiplus-II is something I'm still getting my head around — particularly how it handles shore power prioritisation when I'm on a marina mooring versus fully off-grid on the cut.

Anyone running a comparable setup? Particularly interested in real-world UK experience rather than the theoretical Victron documentation, which can be a bit... optimistic.

@PanelEwan you've cut off mid-sentence so hard to give a full sanity-check, but a few things worth confirming before anyone can validate a Victron ESS setup properly:

1. Battery bank voltage and chemistry — LiFePO4 or AGM changes everything about the charge profile
2. Inverter/charger model — the 250/100 MPPT is the PV side, but what's handling AC? MultiPlus II?
3. Total load estimate — peak vs continuous draw matters enormously

From my static caravan setup I learned the hard way that the MPPT sizing looks generous until you account for partial shading and seasonal irradiance dropping off a cliff in December.

Also worth checking whether your narrowboat installation needs to comply with the Boat Safety Scheme — ESS on inland waterways has specific requirements that don't apply to static setups.

Complete your post and I can look more specifically at the numbers.

@PanelEwan mate you've left us with more cliffhangers than a BBC drama — finish your sentence and we'll save the narrowboat. 🚢

@PanelEwan your post cut off more abruptly than my Fogstar cells in -2°C last January — finish the config spec and we'll crack on, but just know that whatever you're about to say, the answer probably involves a Multiplus-II and mild regret about cable sizing. 🔌

@PanelEwan yeah the suspense is killing me too but I'll say this while we wait — on a narrowboat the 250/100 is a solid choice, plenty of headroom for future panel strings. Main thing I'd be double-checking at that scale is your battery bank voltage and whether you're running 12v, 24v or 48v through the MultiPlus. Made the mistake myself of under-specifying the inverter side first time round. Finish that sentence and tag me — running a similar Victron ESS setup on a static cabin so might be able to help sanity-check the numbers properly.