Solar Arch and Battery Upgrade
I wanted solar for longer trips and future crossings. Queen of Hearts now has a 250W bifacial panel over the stern, along with a 460Ah Epoch lithium battery replacing the two older 100Ah AGMs.
The arch and panel
The solar arch on Daphne, another Nor’Sea, inspired this one. It’s made from one-inch 316 stainless tubing, with 0.12-inch walls on the main verticals and 0.065-inch walls on the supports. The panel angle is adjustable. For now, I’m leaving it fixed.
I also made 3D-printed isolators to keep the stainless tubing separate from the panel’s aluminum frame.
The Renogy panel is bifacial, so it collects light on the bottom as well as the top. I like the idea of picking up reflected sunlight from the water below it. How much that adds remains to be seen.
A Victron SmartSolar MPPT 100/30 handles charging, and I can check the solar output through Victron VRM.
More battery capacity
The old AGM bank totaled 200Ah. Allowing for a 50% discharge gave me about 100Ah to work with.
The new battery is an Epoch 12V 460Ah V2 Elite LiFePO4. Using 80% for planning gives me 368Ah, roughly 3.7 times the old usable capacity. That leaves a 20% reserve; the battery’s automatic protection has a separate cutoff.
The daily goal
My daily goal is to use no more than 120Ah and generate enough to replace it.
Always-on circuits (NMEA, VHF, head, Cortex, 12V ports, etc.) draw 1.72A, about 41Ah if powered all day.
Other daily loads include the fridge, chartplotter, fans, cabin and navigation lights, anchor light, water pumps and propane solenoid while cooking.
One 250W panel gets me closer to the target. With all lights already LED, I’m looking for other ways to lower consumption, such as more efficient fans or VHF equipment. I’m also considering more solar or a wind generator. The engine alternator is a nice last resort.
September update
Across 49 days from May to September without recorded full-battery or controller limiting, solar averaged about 68Ah/day, peaking at 118Ah on August 4 (estimated at 13V).