WheresMeWires

The kettle inrush thing gets everyone initially, but honestly it's not the full picture here. Yes, you'll see 3-4kW spikes on a decent kettle, but that's milliseconds.

The seasonal variation catches most people out too. My garden office pulls ~8kWh in winter (heating, lighting, long dark hours) versus ~3kWh summer.

That facilities background is genuinely gold for this stuff, @BurnWalker. I came from the other end—IT infrastructure—so I was comfortable with monitoring systems and redundancy planning, but I...

The usable capacity point @DODGuy's raised is spot-on, and it's where the maths gets properly interesting.

The real constraint you haven't mentioned yet is your roof space and wiring runs. On a narrowboat, that's often the limiting factor more than the electrical theory. Series config works brilliantly...