Semi flexible solar panels... how long before I really need to connect them

In general, "typical" silicon solar panels (mono and poly crystalline) do not need to be connected to "loads". Keep the electrical connects (MC4 connectors, etc.) clean and dry (MC4 connectors are weather proof once connected).

There are some specific panel chemistry/designs (CdTe--cadmium-telluride) that are sold to large utilities to build solar farms that can be damaged if exposed to sun (the high voltage from being disconnected will damage/ruin the panel).

The bigger deal is if you have shading on a portion of a panel (or panels)... "Dark" silicon cells go "high resistance" when dark and cut the output of the solar array a bunch (50% or more is not uncommon with partial shading). There are bypass diodes (2 or 3 typically for a solar panel) to let current bypass dark cells (to prevent damage to the dark cells), but this does not "fix" the loss of voltage/power.

Another question for you... Do you need semi-flexible panels? The standard panels (solid glass on front side) last much longer than other semi and flexible panels (flexible panels last something like 2-5 years, semi-flex around 5-10 years, glass faced panels around 20+ years). Of course, with glass panels (pretty thin glass, heat treated/tempered glass), if you scratch or drop a tool/rock on the glass, it will shatter and your panel will have to be replaced (tempered glass is stronger than regular window glass, but certainly not shatter proof).

-Bill

Sounds good.

As always, monitor your AGM batteries and their state of charge. See if you can find a chart for your brand/model of batteries and their "resting voltage".

AGM batteries can last upwards of 6 months between charging in 75F / 25C temperatures. Cooler batteries have solar self discharge--Hotter batteries self discharge faster (for every 10C below 25C, batteries should self discharge 1/2 as fast. And for every 10C over 25C, they self discharge 2x faster.

Make sure you monitor your 240 VAC charging system/battery charger. If plugged in right now (while work is getting done), check the "float voltage" for your batteries from the Mfg. specifications. AGM batteries can be damaged if charged for long periods of time at higher voltages.

For a 12 volt bank, typically around 13.6 volts is the "float voltage", and ~14.4 volts is the "absorb charging set point" voltage (generally hold "absorb" voltage for ~2-6 hours or so before dropping back to ~13.6 volts).

You do not want to hear the batteries "bubbling"--And you do not want them venting (hear a hissing sound).

Have a great time! I have watched a couple of programs on "narrow boating" in the UK. Beautiful country and amazing that the commercial canal transport system has been (much) resurrected and not turned into freeways/filled in for building sites (something like 300+ years of history).

-Bill