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Off-grid Solar Powered Security Camera

saxon11

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Joined
Sep 29, 2021
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I've built a working prototype of an off-grid cellular powered security camera powered by solar panel using an agm battery and an oversized 100w solar panel.. i'm looking to refine it and make it smaller and more efficient with lithium battery. i saw this post: https://dakotalithium.com/2019/10/30/what-is-the-best-battery-for-cold-weather/. the picture in stahlin enclosure is something like i'll use. temp in mn get to -20 degrees. my draw will be around 10w for hotspot and camera. i'll prob need to add some sort of elec heat, which is another 40w if running. that puts me at 50w max per hour.

I wouldn't need any heat if my mobile hotspot operates in extreme cold. According to Dakota's website, their lithium batteries work at -20 degrees. questions:

- 10a 12v battery seems like could be good fit?
- do i need a charge controller if charged by solar? currently i use a cheap one with my agm.
- 25w solar panel big enough (assume 5 hours sun a day)

thank you.
 
Camera use is 240 wh per day battery you picked is only 120 wh solar is only 125 wh a day in perfect conditions. So the answer to number one is NO answer to number 2 is YES answer to number 3 is NO. 10 watts seems high for a camera and hotspot.
 
Last edited:
i saw this post: https://dakotalithium.com/2019/10/30/what-is-the-best-battery-for-cold-weather/. the picture in stahlin enclosure is something like i'll use. temp in mn get to -20 degrees
Please check to see that you can charge the battery that cold. My battery has a spec similar to discharge until -20, but can’t be charged below freezing. For this reason, lead acid may be the way to stay for you. You can add a heater, but that complicates things.

Here is the results from the off grid calculator for a 100 watt panel for a central AZ:
0BC5A0F0-14D4-4B58-BD2B-029B3D8C7BFA.png
And the same for a poor solar area like Seattle:

619F5310-F3FC-41A0-B93B-0AA5B64CA1FB.png
Both places don’t work. The battery is drained completely empty every single day. If you use the off grid calculator in signature block, you can change some data bases off your location, more solar, more battery. You’re looking for % with days battery empty really low if you have a generator backup, and if you don’t needs to be almost 0%.
 
Please check to see that you can charge the battery that cold. My battery has a spec similar to discharge until -20, but can’t be charged below freezing. For this reason, lead acid may be the way to stay for you. You can add a heater, but that complicates things.

Here is the results from the off grid calculator for a 100 watt panel for a central AZ:
View attachment 75496
And the same for a poor solar area like Seattle:

View attachment 75497
Both places don’t work. The battery is drained completely empty every single day. If you use the off grid calculator in signature block, you can change some data bases off your location, more solar, more battery. You’re looking for % with days battery empty really low if you have a generator backup, and if you don’t needs to be almost 0%.
What did you have running/using the battery that drains it each day?
 
What did you have running/using the battery that drains it each day?
Trying to explain the Off Grid Calculator which should help you plan by putting in your location, the WH used per day, size solar array, size battery, and how low the battery can go before it shuts off. You can change those numbers however you want based off what you want to get.

1639361645846.png

I input data you mentioned in post 1 for a 250 wh drain per day, 100 watt panel, a 120 watt hour battery, and draining the battery to 40% (Uses 80 ah) before auto shutoff. So, this means if you have sunlight, there's enough power to charge the battery and run your system in the day, but sometime between sunset and sunrise, those batteries run out of juice.

This Basics of OffGrid Design help explains system sizing.
 
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