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Switching between mains power supply and 12v solar system

Scoldingice

Sep 20, 2016
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Sep 20, 2016
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I'll apologize in advance for my lack of knowledge but desire to electrocute myself anyways.

Ok so I want to build a battery backup for my security cameras. I thought a relay be able handle the switch between mains and my solar system. Unfortunately the relay delay is too long. Each camera is rated at 12v 1a, but they are able to handle the 14.5v my solar system maxes out at during charging.

I was wondering if I could just put a 16v 1000uf capacitor on each camera to handle the switch over?

Another idea I have is to use two diodes so that when the solar system is 13-14v the cameras will use the solar panels until it levels off at 12.9v during the night and then just run off the mains power supply that I would set at 13v. Also would this allow for the cameras to running off the battery if a mains outage happens.
 

Harald Kapp

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Nov 17, 2011
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Imho diodes are preferable over a relay. Add a capacitor nonetheless to smooth out any irregularities from the solar panel. Use at least 25 V types (electrolytics should always be oversized to increase lifetime).
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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The best solution is probably an MPPT regulator with a max output voltage above that of your DC supply but below the max for the cameras. If you isolate both using diodes, the solar panels will provide the most power they can with any gap being delivered by the dc source.
 
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