Julie2Oregon
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# Posted: 11 Jan 2015 06:38
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So, I'm looking at the supplies for my solar power and am going to give the installer in Oregon a call to chat about it this week.
The LFP battery looks like a great solution. I read the brochures and info at the website but have a few questions. The 5.2 kW battery seems ample since I estimate that I'll need about 1.8 kW to run my fridge, water pump, TV for a few hours a day, and a couple of LED lights. If I have that much storage, I found a very energy-efficient cabin ceiling fan, too, designed to move the hot air out of the loft.
I'm going to have stairs going up to the loft against an outer wall and storage under the stairs. Is it possible to store the LFP battery in that area under the stairs with the wiring going through that outer wall in the compartment? That would keep the battery warm but ventilation would also be possible.
How many amps and volts and what sort of charge controller do I need? I was looking at them and getting really confused. Is Midnight Solar a good brand?
Also, I am looking at getting 7 265-watt mono solar panels that are supposed to produce from dawn to dusk and on cloudy days. Is that real or hype, haha? Are fewer large-watt panels good or should I get more lower-watt panels?
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creeky
Member
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# Posted: 11 Jan 2015 11:49
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My .02.
For a solar controller I prefer the morningstars. they use the least idle power. they are air cooled no fan to break down/wear out. they are the #1 selling solar charge controller for a reason. the mppt 60 has a web server (so you can spend hours of your life watching the voltage/watts of your solar panels fluctuate in real time). They are programmable for LFP. and morningstar has a new ground protection device which is pretty cool.
Your LFP battery pack will give you 3 kw of power reliably for 8-10 years. Nice.
Yes. The LFP battery can go under the stairs. And it does not need to be vented (as I understand it, check with the mfct to verify).
The 5.2 is a 24 volt pack.
So you need a 24v pure sine inverter. There are a lot of good ones out there. The thing with inverters is the expensive ones are just better. They offer a wider voltage range (not so important with LFP mind, as you don't need to equalize). Handle a wider range of temps. Gee. Again, you're storing indoors, so? And some have chargers built in.
I use an external charger. An inverter with a built in charger offers ease of use. But it's also a thing that can break. So if the ats breaks, then the charger becomes useless and all you have is an inverter. Or the charger breaks. Or the inverter breaks ... and you're replacing a bigger $$$ unit. Still.
A 1.6 give or take inverter/charger, with your loads, should work nicely. I would go spendy just to buy some reliability. I like the TBS inverters from Europe. But I am given to understand that the american ones are okay too.
Remember, your inverter is always on. Some inverters eat a lot of power. 35 watts might sound small but that's 840 watts a day. My TBS uses 10 watts. That's 240 watts a day. Saving me the energy (600 watts for free!) that my fridge uses.
Mono panels have the advantage that they do produce more power when shaded/cloudy. Big panels have the advantage that they are manufactured in much higher quantities and probably better materials. I'm a proponent of higher voltage arrays and panels. Thinner wire, longer distances, better performance, in a nutshell.
I'm also a proponent of "overpaneling." Overpaneling is often confused with overcharging. They are two different things.
Over paneling means that you put more watts of solar up than your controller specifies. Not all controllers can handle this reliably (the morningstar does tho). The advantage of putting 1.8 kws up for your 24v battery (which at 60 amps means a 1500 or 1600 watt array is about max in terms of power handling) is when the sun is not full on, on cloudy, hazy days, in fact the vast majority of the time, you're making more power. This is a good thing as you will find out.
I hope this helps. Remember, I have a web blog and a donation button. All beers appreciated. Also you can contact me for more detailed info there.
Hope this helps.
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