How dock solar works

What an 800‑watt panel gets you

A lot of people call and ask what we'd charge to put in an 800-watt panel. It's the right instinct. The panel is the part you can see. It's also only the first piece.

A panel makes power while the sun is up. To use that power at 9 pm, or to start a lift motor that pulls more in one second than a panel makes in a minute, you need a battery. The panel refills the battery all day, and the battery does the work. A charge controller sits between the two so the battery fills at the right rate and never overcharges. If you want a normal wall outlet, an inverter turns 12-volt battery power into 120 volts. Around all of it goes the fusing, the locked weatherproof box, conduit to each outlet or appliance, and the small radio controller that puts the whole system in your phone.

So when you ask about the panel, what we'll ask back is what you'd like to run. That answer sets the size of every piece.

The three pieces

The panel makes the power.One 200-watt Renogy panel on a Smith Lake roof puts about 870 watt-hours into the battery on a summer day. More panel, bigger daily refill. Panels carry a 25-year warranty and have no moving parts.

The battery holds it.We use lithium iron phosphate, the same chemistry as in an electric truck, because it takes 5,000 or more charge cycles, needs no maintenance, and doesn't mind a hot box. Battery size sets how long you can go without sun. It also reports its own state of charge and health to the app, so you always know where you stand.

The outlet delivers it.A 120-volt GFCI outlet runs anything with a normal plug, your boat lift included, with nothing on the lift changed. A 12-volt outlet carries low-voltage power straight from the battery to the dock gear we supply.

What things use, and what the sun gives back

Everything on the dock draws some amount of power for some amount of time. A lift motor is the biggest draw out there, and it runs about a minute per trip. A dock fridge draws a little, all day long. String lights hardly register.

On a typical summer day on Smith Lake, the sun puts back:

That's the whole sizing method. Add up what you'll run on a normal day, compare it to the daily refill, and give the battery enough reserve to ride out a cloudy stretch. The small system covers two lift trips, lights all night, and a few hours of fan, every day. The large one keeps a full-size fridge cold, runs the lift six times a day, and still holds about two days in reserve.

Solar compared to shore power

Bringing power from the house means an electrician, a trench or conduit run that on Smith Lake is often 100 to 300 feet of rock, a sub-panel and GFCI protection at the water, an inspection, and a power bill for the dock from then on. We see that work quoted between $5,000 and $15,000 before anything gets plugged in.

A solar system is built at the dock. Nothing gets dug. There's no utility hookup, so there's no bill, and when the power goes out at the house the lift still comes up and the lights still come on. The 120-volt wiring is a short run from the box to the outlet, in conduit, with GFCI protection. There is no line from shore in the water.

Solar does have a limit, and we'd rather say so up front. It's a daily budget. A space heater, a window air conditioner, or a water heater would empty it in an hour or two. If you want those on the dock, shore power is the better fit and we'll tell you that. For everything else people run on a dock, solar covers it with room to spare.

12 volts or 120 volts

A 120-volt outlet is the one you already have in the house. The lift plugs into it, and so does a box fan, a TV, or a phone charger.

A 12-volt system carries low-voltage power straight from the battery. It can't shock anyone, which counts for a lot at the water, and it runs the 12-volt gear we supply and wire in, string lights, a fishing light, a wash-down pump, a marine fan, a dock fridge. It won't run a lift, a box fan, a house fridge, or a TV.

There is one low-voltage way to run a lift. We offer a full replacement blower motor and control box that runs on its own solar-charged 24-volt battery bank, and it's a good system. For most docks we still recommend the 120-volt outlet, because the lift stays exactly as it is, the motor warranty stays intact, and the other plug on that outlet runs everything else.

Lift owners usually want the 120-volt outlet. People who mainly want lights and a fishing light are usually better served, and better priced, by 12 volts. A lot of docks end up with both.

What helps us quote it right

When you call or text, these are the things that let us size it on the first try:

• what you'd like to run, all of it, lift through phone chargers
• whether it's weekends or every day
• whether the dock roof sees open sky at midday (a photo answers that)
• if you have a lift, whether it plugs into an outlet or is a HydroHoist you'd rather convert to 24-volt solar
• where a locked box could sit, ideally under the roof and out of the sun

Send those and a picture of the dock to (205) 721-3830 and we'll come back with a size and a price.

Why we'd put solar on any dock

Our own dock runs on it. Lights, fishing light, fridge, pump, fan, all of it 12 volt. Since we don't have a boat lift, our full system is 12 volts. What we like about it, and what our customers tell us they like:

• nothing dug between the house and the water
• no power bill for the dock
• the lift and the lights keep working through an outage
• no shore line in the water
• Victron controllers and inverters, lithium batteries, and 25-year panels, the same parts on our own dock
• every outlet and appliance on its own switch in the app, with the battery level always in your pocket
• installed by the person who answers the phone