PV heating for chickens to melt ice

[efficientPV]

A PV heating for chickens to melt ice was posted a while back. It didn't really cover the issues in doing this

E

Thread 'Panel directly wired to DC heat tape?'

Dec 12, 2024

Somewhat of an off-grider/homesteader question, but this sub forum seemed most appropriate.

Any reason I can't take a 50-100 watt panel and directly wire it to DC heat tape to help keep water for chickens from freezing during the day? Not asking about effectiveness, just whether the panel would actually turn on the heat tape intermittently as it gets sun or not. I wasn't sure if some logic was needed for panels direct to appliance.

An example of the heat tape:
DC heat tape (amazon)

• eson
• Replies: 7
• Forum: Danger Zone! (Advanced User Experiments Only)

The resulting solution the OP went with was a 12V 50W panel and a silicone pad rated at 24V 80W that was 7.3 ohms. I didn't think that would be enough given winter conditions. Since then I have been contacted by another trying to do the same thing with a 200W12V panel and a 1.5 ohm heating element that wasn't working well. That element has since been replaced with a 4.6 ohm element. Results at this time are not available but he did provide a chart for power production at different currents. Unfortunately, the chart starts at 2A which does not reflect probable low currents less than 2A. A 10 ohm would work better.

All solar is local. I just started testing with my winter conditions with a 100W 12V panel I borrowed and currents of less than 0.8A are common. 0.8A and a 7.3 ohm element = 4.6W. A 50W panel would be half that current and be about 1.2W. My guess is it takes about 20W to be successful melting ice. With direct connect heating element resistance should be designed to top out at about that power. A big panel is needed just to supply that much in winter. I was working on a simple LM358 op amp design that would be cheap just for 12V panels. After posting the design I was sent this video.

While that poster has corrected some of the design is shows the simplicity. This as well as my chicken heater can be used on any array voltage and wattage with some component changes. Here is the one I built, only 15 parts.


In the test setup with a 12V 100W array the power was only about 6W. This is winter and that does help. It demonstrates the need for a power point control in this application with just 0.3A.

 

[orangezero]

One way to approximate the max power point would be to use a string of diodes to approximate something close.

Or, you could use a long length of thin insulated wire instead of a fixed resistance heating element or fixed length heat tape. This allows the user to self select the length to get the exact resistance in ohms required.

 

[efficientPV]

Diodes are a reasonable option since the operating temperatures are known and this is a low density heat application. It would take 32 diodes in series and some of these water sources are metal pans. It is still requires a lot of assembly that most avoid. Heaters have a lot mor flexibility and can limit watts. I have never understood the appeal of diodes to some.

 

[crossy]

Going off on a different tack!

How well insulated is your Chicken Hilton?

Each chook will generate about 10W of heat, keep that heat in and you may not need to heat the water to keep it from freezing

 

[Deveak]

I have an idea I have yet to implement. Old electric hot water tank off facebook marketplace. Cut holes and drill and tap for stainless steel watering nipples. I think they make them for chickens as well. You need to anchor it down though since its top heavy. PV panels and DC heating elements. Preferable low voltage since animals are prone to electric shock. Thermostat would need to be extra low to avoid scalding and you would need to bleach or occasionally let it get hot to kill legionnaires bacteria. Wrap the upper section in insulation and wrap sheet metal around.
The nipples will remain unfrozen since heat will transfer through them easily.
A highly insulated hot water tank shouldn't freeze and its a decent sized 40+ gallon water tank for the animals.