Solar Heated Chicken Waterers: What a Panel and Battery Would Have to Deliver

The short version

The search for a solar water heater for the coop starts from a real problem: the coop has no outlet, and the water freezes. The answer has two parts.

First, heating water with solar electricity is possible only as a system you assemble, and the numbers below show that it is large for what it does. This page therefore has no solar pick. Second, the sun is still useful. The methods that extension services actually list for unpowered coops use sunlight directly, without a panel.

No independent test of a solar heated poultry waterer was found. Everything below rests on rated values that anyone can check on a nameplate.

Step 1: what a heated waterer uses

Energy is power times time. Complete heated waterers draw 60 or 100 watts according to their manufacturers, heated bases 28 to 125 watts. Unlike a coop heater, a waterer has no off-hours: in a cold spell the water can freeze by day as well as by night. A solar system would have to cover the whole day.

These ratings are the most a unit draws. The units with a thermostat switch off when they are not needed: the Farm Innovators instruction sheets state that the heater operates only when temperatures fall below 35 °F. How much of a freezing day the heater then runs is not stated by any manufacturer. A solar system has to be sized for the bad day, though, not for the average one, because the bad day is when the water freezes.

Step 2: what a battery holds

The reference is a 12-volt battery with 100 amp-hours. Volts times amp-hours gives watt-hours: 12 × 100 = 1,200 watt-hours, or 1.2 kilowatt-hours. That is the nominal content on the label; a battery cannot deliver more than that.

To see how long a battery lasts, divide its watt-hours by the heater's watts. We print no runtime table: the result at full power is easy to work out from the two labels, and the real runtime depends on how long the thermostat keeps the heater on, which no manufacturer states. What the labels already show is that a heater of 60 watts or more, running through a freezing day and night, takes more than the nominal content of one such battery, with nothing in reserve for a second day.

There is a second hurdle. The heated waterers on this site are built for household current. The instruction sheet of the HPF-100, for example, specifies 120 volts AC. A battery delivers 12 volts DC, so an inverter has to sit in between, and it has losses of its own that this calculation leaves out.

Step 3: what the solar panels have to deliver

Whatever the heater took out, the panels have to put back before the next evening. In midwinter the day is the short part.

We give no panel size. The wattage printed on a solar panel is its output in full sun, and a winter day offers that for only part of its daylight hours, if at all. We did not look up sun hours for any location, and no manufacturer states how long its heater runs in a day. A run of overcast days calls for more batteries on top.

The low-wattage exception, and why it is not a pick

One device stands out in the table: the insulated heated base from My Favorite Chicken. According to its manufacturer it uses 28 watts and has a low-voltage, 24-volt DC connection on the heater side. With the lowest rating in the table, it is the heater here that asks least of a battery.

It still is not a solar product. The manufacturer's page describes mains operation through a power adapter and mentions neither battery nor solar operation. It also asks for a covered, dry, wind-sheltered location and states that the base is not waterproof. Connecting it to anything other than its own adapter is outside what the manufacturer documents, and this site does not recommend it. The base itself is described under heated base for a chicken waterer.

Solar without a panel: what the sources list

The extension fact sheets do use the sun, in the plainest way.

• Black rubber tubs in sunlight. The University of Maryland Extension lists them because they absorb heat, do not crack and let you break the ice out.
• A clear cover around the waterer. Maryland describes a small greenhouse built of old windows or clear plastic that heats itself from sunlight.
• Floating ping-pong balls. Listed by Maryland as a help against freezing.

None of these comes with a measured effect, and all of them work by day. At night the unpowered answer is insulation plus a swap in the morning.

What helps a coop without an outlet

An insulated waterer. It has no heater and needs no power. It lengthens the time until the water freezes.

No power at the coopAd

Omlet

Omlet insulated waterer, 3 gal

An insulated 3-gallon waterer without a heater: it slows freezing where no outlet is available.

Why here: No cord, no panel, no battery. The manufacturer states that the insulation keeps water flowing for 10 hours at 10 °F. That is the maker's own figure, and insulation delays freezing without preventing it.

Best for: Coops without electricity, as a way to stretch the time between water changes.

What speaks for it

• Needs no electricity and no cord
• The manufacturer states that the insulation keeps water flowing for 10 hours at 10 °F
• Cups and nipples are both included; anti-roost lid (manufacturer)

What to know first

• Insulation delays freezing; it does not prevent it
• The 10-hour figure is the manufacturer's own; no independent measurement exists
• Highest price class of the waterers compared
• In sustained hard frost the water still has to be swapped by hand

Type

Insulated waterer, unheated

Power

none

Capacity

3 gal

Use

Cups and nipples included

Rated to

10 hours at 10 °F (manufacturer's claim)

Price class

premium

See it in the comparison

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What that figure means for a winter night is worked out under insulated chicken waterers.

A routine. The University of Wisconsin–Madison Extension suggests two waterers that are alternated while the idle one thaws indoors. All unpowered methods are collected under keeping chicken water from freezing without electricity.

A fixed supply, if the winters are long. Where water has to be carried twice a day for months, a permanent, grounded outlet and a mains-powered heated waterer are the setup on which the numbers work. The NFPA tip sheet for backyard coops asks for electrical work by a qualified electrician. See electricity to the chicken coop and the overview of heated chicken waterers.

Bottom line

Heating water takes energy around the clock in the weeks with the least sun. A waterer rated at 60 or 100 watts, heating day and night in a freeze, asks more of a 12-volt, 100-amp-hour battery than its nominal 1.2 kilowatt-hours, and the panels have to refill it every short winter day. Use the sun directly by day, insulation by night, and a daily swap. The same arithmetic for heating the birds themselves is on the page about solar chicken coop heaters, and the consumption figures for mains power are under how much electricity a heated chicken waterer uses. Which small loads do suit a panel is covered under solar power for a chicken coop.