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Small Cabin Forum / Off-Grid Living / Thoughts on this system?
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rachelsdad
Member
# Posted: 10 May 2017 11:13
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https://www.costco.com/Grape-Solar-400-Watt-Off-Grid-Solar-Panel-Kit.product.10004928 8.html.

27 ten watt LED bulbs..way over estimating at 10 hours a day, weekend use primarily.

Shurflo water pump...no fridge, (propane), no other electrical demands.

Thoughts on components?

Steve_S
Member
# Posted: 10 May 2017 13:27
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Grape Solar is at least double the cost for what you get....
100 Watt / 12v Panels
PWM Controller
Reasonably good inverter and No Batteries

The consumer Plug'N Play kits like this & Sunforce (Coleman) are big dollars for what they are...

Would it run your stuff, quite possibly IF you had enough battery BUT I do think you could do much better if you did not look at these consumer plug'n play kits and maybe looked more at RV/Boat Kits... This of course would mean having to get your hands a bit more grimy and do some of the extras but that does not require a major skill set or ability.

razmichael
Member
# Posted: 10 May 2017 13:54
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Although I agree with Steve that the plug and play kits are overpriced - and often you are paying a lot for convenience of a kit, the components in this package are decent and the overall price is not really that bad. However, it is not really a kit but a package and you would need to add the cost of the batteries, battery cables (not cheap to handle the amps), fuses, etc.

Quick look at Amazon
Inverter - 450
CC - 100
Panels - hard to say because of shipping, etc but 400-500 (and you could certainly do better than this)
Wiring - 100 (on the high side)
so the Costco price is not bad given the great return policy.

No doubt you could put together equal or better for less. Given your 120 volt requirements seem to be only lights, do you need a 2000 watt pure sine wave inverter. Depending on your wiring options, you might be able to use 12VDC LED lights (same form) and run everything 12v - although there are other gotchas with this.

Just make sure you consider the battery costs and the others bits and pieces so you fully understand your total cost. And maybe do a slightly more accurate use assessment - are you really going to have 27 lights on 10 hours a day? perhaps a little conservation is in order. Doing this assessment is vital to figure out your battery needs. Also consider if you will need more later - this will impact the cost of the components unless you plan on replacing when the needs change.

rachelsdad
Member
# Posted: 10 May 2017 15:27
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razmichael,

I've wired the house w12g romex so I can go either way.
I used the 27 lamps at 10 hours a day as an overestimate, a BIG overestimate...but I do know my wife's passion for lots of lights in the house..so yes, use would probably be much lower.

What were the components you were peeking at?

Batteries, I am having a difficult time getting good response for the lithiums save for The Electric Car Company in Utah...good people there. I just may buy 6-8 6v golf cart batteries, (a friend is a distributor, I pay $90 per), bita and pieces...frankly i am afraid of that but I've met a good installer up in St Lawrence County who is going to put this all together for me...lot of piece of mind there.

SteveS...not afraid of the grime...wired the place myself, took 49 loads of crud off the island...but frankly I'd rather pay a few bucks to make sure I have the widgets where needed...but i wholeheartedly agree, I'd prefer to customize, but if this basic system would "work" I'd use it as a baseline to upgrade parts...(of course after bugging you all here first).

Thanks for the replies

NorthRick
Member
# Posted: 10 May 2017 15:52 - Edited by: NorthRick
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There are a couple of problems with that setup. The primary one is that you still need batteries. Second, it's a 12 volt setup which means the panels are about twice as expensive per watt than if you bought panels that are higher in voltage. Third, a 2000 watt inverter is too much for a 12 volt system. 2000 watts at 12 volts is 167 amps. You need fat wires to safely handle that many amps.

As for size, not counting the water pump, you list 2700 watt-hrs of load a day. Ideally you'd only draw down your batteries 20% each day (you can draw them down more but they won't last as long) so ideally a battery bank rated for 13500 watthrs. At 12 volts that's 1125 amphrs, which is a sizable battery bank. To properly charge that you'd need about 1350 watts of solar panels.

I'd reassess what your true loads are - 27 ten watt LED lights is a lot and I wasn't including the pump in the above numbers. You also might consider a 24 volt system, cheaper panels, and smaller wires and fuses.

rachelsdad
Member
# Posted: 11 May 2017 14:26
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Second, it's a 12 volt setup which means the panels are about twice as expensive per watt than if you bought panels that are higher in voltage. Third, a 2000 watt inverter is too much for a 12 volt system. 2000 watts at 12 volts is 167 amps.

Not afraid to admit that even after hanging out here for 12= months I did not know the difference....

Thanks

creeky
Member
# Posted: 11 May 2017 18:35
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I'm writing a solar guide and have published a "simplified solar schematic" on my website.

Is anyone building a diy off grid system. Could you have a look and give me feedback? Thx

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