Help Understanding/Designing my off grid system

[jyonke15]

I have a couple of acres that I'm developing slowly and will someday build a house. But in the meantime, I have a camper, shed, outhouse and I want to add a chicken coop. I've been getting by with a couple of small self contained solar lights and exhaust fans from Amazon and Harbor Freight but my next project is going to push me into needed something more. I don't live out there full time, so my day time usage is isn't much at all. In fact, it can be zero for up to a week at a time. But I plan to add a chicken coop in the spring and since I'm in SE Wisconsin, I need to keep my water collection system from freezing from the point of storage to the point of deliver in the coop. That might look like a tank heater, heat tape and a trough heater all in use together from December-March. I don't plan to have a very long distance from the panels to a controller/inverter.

I just purchased used (6) 235w Trina panels from a local source. I attached a picture of the specs from the back of one of the panels. I can use all these panels, only use some of them, or I can get more if i need to.

I think my main concern is having enough stored energy to discharge overnight, knowing I live in a region that averages 3.45 hours of peak sunlight from December to the end of March. I have an idea of what type if power I might be consuming, estimating a high of 10,000 watts per overnight if I run everything constant.

From here, I'm all ears, looking for direction on everything from Panel wiring, controller to inverter to batteries/wiring etc. I have been looking at buying a some number of 6v 225ah batteries and wiring them together.

 

[sunshine_eggo]

Those panels facing due South tilted at 42° with unshaded exposure from sunrise to sunset can produce the following on a monthly basis:





This is for your list city/state. Your specific location may vary. If snow is a factor, you may want to consider a 60° tilt to improve the winter hours and have a lower tendency for snow accumulation.

You don't want to plan on averages. Plan on the low. Weather is the bigger driver.

You may want to output the hourly CSV and look at the actual performance for sunny and shitty days alike.

If you meant 10,000Wh overnight, your array is grossly undersized. At no time of year can your array produce more than about 8200Wh/day.

More homework - detailed energy audit in line #1 of my sig. Wiring comes later.

 

[chrisski]

This post is from a guy that designs solar telecon with generator backup and has a 5 day battery backup:

Solar Off-Grid Battery Design - Solar Panels - Solar Panels Forum

Discuss remote solar applications for homes, cabins, RV and boats. If you have a question on equipment for an off grid system, such as charge controllers or inverters, then post your question in this forum.

www.solarpaneltalk.com

A reasonable worst case scenario is probably five days for Wisconsin to avoid a generator as much as possible, but could be much less if you accept the use of shore power or generator.

Also, the cheapest way for the amount of energy you are asking for is a grid tied system. Depending on the utility agreement for your area, you could "bank" the summer excess kWh production and use this in the shorter winter days.