diy solar

diy solar

The Warehouse

8_Hz_WAN_IP

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We want to progressively accumulate solar energy equipment until it can handle our full energy consumption. We've been living in it for almost 3 years now while attending college.

We own a 30' THOW from Alpine Tiny Homes: https://tinyliving.com/warehouse-alpine-tiny-homes/

We just recently bought 2x 350W panels from SolarPanelsFreeShipping for exactly $500 (incl shipping). For the price, shipping, and capability, I can't find anything stronger. See pic for specs.

Now I'm looking at a Victron controller, and DIY batteries, but I don't know what size to get for functional solar now with future proof capacity for off-grid.

I measured the amps I'm currently pulling with my clamp meter, and my consumption atm is 14A @120V at the panel. At night, it was only 3A @120V at the panel (much less is used at night).

If I DIY a LiFePO4 battery bank to handle this usage, how large would it be/much would it cost? Also, what kind of charge controller and inverter should I get? I have lots of thoughts, but I wanted your feedback. How would you go about it?

Screenshot_20200807-163745_Samsung Internet.jpg
 
Instantaneous current measures don't tell you what you need to know. You probably want quick answers, but if your goal is to design a system that meets your needs and possible future expansion, you need to start at the beginning.

Guessing leads to under/over-designed systems. Data leads to optimized cost and quality of life.

Start with the energy audit link in my sig. List the actual devices, power consumption and run time.

Check item #5 in my sig and determine solar hours per day for your location and select the panel orientation you'll be able to accommodate. Find the month with the lowest output and enter that number in the spreadsheet.

Think ahead to how you want to expand it in the future and design it accordingly. Once you have the design established, you can figure out how to piecemeal it in stages.
 
consumption atm is 14A @120V at the panel. At night, it was only 3A @120V at the panel (much less is used at night).
Lets do some math to get some ballpark numbers.

Assuming you're at the vernal equinox, 12 hrs day, 12 hrs night
14a x 120v x 12h = 20160wh
3a x 120v x 12h = 4320wh
daily consumption using your numbers is 24480wh.
Using 5h of full sun (ymmv), you would need 24480/5 = 4896w of panels operating at 100% efficiency.

If I DIY a LiFePO4 battery bank to handle this usage, how large would it be
With 5h of full sun, that puts you on battery for 19h (roughly).
24480 x (19 / 24) = 19380wh of battery
19380wh / 12v = 1615ah (that is a LOT)
 
I appreciate both of your quick responses. If using instant current measurements isn't the best way to go about things, is there a way to test the whole house current over time? Is there a device that calculates total KWh/day so I can graph daily usage over time? I know Kill-A-Watt plugs can be used for single appliances, but I don't want to have to buy one for every appliance or even use one for all appliances. Plus, there are systems such as my mini-split that are directly wired to the house that the Kill-A-Watt wouldn't easily work with.

I'm imagining some kind of split A/C current inductor connected to a digital display that I can clamp over the house common. Does anyone have any recommendations?
 
Is there any usage info on your monthly power bill?
Does your meter display the number of watts being used currently?
Right now, my tiny house is in an RV park. We manage it, so its free rent. We only have to pay for electricity. We don't see the electric bill though because the landlady has everyone pay a set amount. There's no way for me to see the bill/actual usage information. Do you know of a device I can use?
 
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