Setup, Would there be an imbalance with this setup?

[Aspire]

Yep, you got it. It won't handle shade well... if any of the 4 panel group gets partially shaded, it will affect every panel in that string, but again, I think this is the best you can do with what you've got.

luckly, all of these panels are on top of a shed, and have the same amount of sun all the way around. no obstructions anywhere either.

[max2k]

luckly, all of these panels are on top of a shed, and have the same amount of sun all the way around. no obstructions anywhere either.

you picked very challenging project for learning: as your temp can go to -30 you need to ensure your batteries are fully charged otherwise their electrolyte becomes just water and readily freezes tearing apart their cases. With -30 I'm not sure electrolyte itself won't do it either, I forgot the freezing point temps for different SOC. On top of that batteries perform poorly at those temperatures as they're still based on chem reaction and that strongly depends on temp.

[Mike90250]

image_8662.jpg Here's the battery freeze points

[Aspire]

you picked very challenging project for learning: as your temp can go to -30 you need to ensure your batteries are fully charged otherwise their electrolyte becomes just water and readily freezes tearing apart their cases. With -30 I'm not sure electrolyte itself won't do it either, I forgot the freezing point temps for different SOC. On top of that batteries perform poorly at those temperatures as they're still based on chem reaction and that strongly depends on temp.

The thing is, the battery's are made for cold weather, but yes, lead acids do preform really poorly in the winter. lucky, no usage will be seen in the winter, and even if they do, it will only be once. These battery's are made with Calcium-lead alloy instead of pure lead. (not sure what you would think about that.)

[max2k]

The thing is, the battery's are made for cold weather, but yes, lead acids do preform really poorly in the winter. lucky, no usage will be seen in the winter, and even if they do, it will only be once. These battery's are made with Calcium-lead alloy instead of pure lead. (not sure what you would think about that.)

water is water and if you just leave them outside in that temp you'll find their cases cracked next spring. I read somewhere ppl from the area go to lengths to keep their batteries from freezing in the winter in case they want them outside by installing temp sensors and heaters. I can't provide exact details but please read up on this, freezing water is no joke- ice takes up more volume than water it froze from cracking any container it is in unless of course the container has some 'soft' parts which would deform and let ice take extra space it needs. I doubt batteries have such feature.

Mike conveniently posted table above showing among other things you won't be able to discharge your battery below 75% in the winter time to remain in safe territory from freezing point of view leaving you with only 25% available capacity.

[Sunking]

sensij this setup isnt purely for making a house run, its just to power a shed for free. The 20 watt panels are from 2 - 72watt kits, which i bought on the cheap from my work. what would be the problem with the batterys?, or does the application clear that up? Also, the panels are rated for 18watts, but ive seen them produce 20 watts.

You have a lot to learn. Off grid power will cost you 5 to 10 times more than buying it from the power company.

[Aspire]

max2k well, ill just pull them inside during the worst of the winter then.

[Aspire]

Sunking well, that i knew. But i have only spent around 500$ for all of this anyways, so meh. this is just hobby nonsense, with, well, a bit of sense thrown in so i can actually learn something. if i wanted to power the house, i would spend the 10k + (probably around 20K actually) to do it.

[max2k]

max2k well, ill just pull them inside during the worst of the winter then.

good workout I guess In terms of learning for the money you're about to spend you could buy decent scope, power supply and get yourself busy with some embedded programming- Arduino family provides relatively easy to work with platform. This way you'll learn a lot and have 0 chance to burn something valuable. All that knowledge will be quickly transferable to solar/batteries/anything electrical later. Just a thought.

[ButchDeal]

max2k well, ill just pull them inside during the worst of the winter then.

Just build a sealed battery box with vent pipe to outside.

[max2k]

Just build a sealed battery box with vent pipe to outside.

he'd need heater and some automatic 'watcher' to keep an eye on that- -30C is no joke and it usually comes in the middle of the night or what is worse-early morning. It takes single 'accident' to render his batteries junk.

[ButchDeal]

he'd need heater and some automatic 'watcher' to keep an eye on that- -30C is no joke and it usually comes in the middle of the night or what is worse-early morning. It takes single 'accident' to render his batteries junk.

That's why I was seconding the keep them inside but with a battery box.