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As the title suggests, I'd like to power a Dropcam without laying new wire in our community garden (code enforcement makes wiring a headache). When I wired my Raspberry Pi to work off solar power it was easy because I was only going to be using it in sunlight and if it turned off I would simply turn it back on. With the Dropcam, though, the intent to is to keep an eye on everything at night and weekends with as minimal interruption as possible.

After using my Pi setup as a base and reading this post, I'd like to confirm with you guys that something like the following is sufficient for my needs. Is it too much? Too little? I'm in Santa Monica, Ca so there's typically plenty of sun. According to the diagrams I've seen, this area gets about 6-6.5 sun hours daily, which seems more than enough to me to power a small USB device.

Specs on the Dropcam:

  • Input: 50/60Hz 0.5A

  • Output: 5V-2A

  • Wifi: 802.11b/g/n 2.4GHz (not sure if this has any influence)

Proposed setup:

  • 12V/12aH deep cycle battery (e.g., this)

  • 50 watt panel (e.g., this)

  • Charge controller (e.g., this)

  • Inverter (e.g., this)

Forgive me if this question has been answered. I've browsed the questions here and attempted the calculations, but it can be overwhelming for someone whose only experience with electrical products resulted in a zap or two ;)

Edit: I'm also open to any other suggestions! I'm not married to solar, so if there is a simpler, cheaper, or more viable solution feel free to share.

Cheers

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    \$\begingroup\$ I'd be tempted to just run the device off of 5 volts that is generated by a buck converter attached to the batteries. It is simpler and cheaper. \$\endgroup\$ – HL-SDK Jan 21 '14 at 19:50
  • \$\begingroup\$ @HL-SDK would that allow me to bypass the need for solar altogether? I considered this as a possibility but wasn't sure how long the batteries would last. 5 volts doesn't seem like much, but I thought it might add up. \$\endgroup\$ – emsoff Jan 21 '14 at 20:12
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    \$\begingroup\$ @jboneca it's not the voltage, it's the capacity, and the actual current draw of the camera. Does it actually take 2A, or much less? Does it have a linear regulator inside that can be bypassed for a more efficient use of power? First things first, hook it up with a ammeter or multimeter between the camera and the power supply, and see what the maximum load is. With that, you can correctly size the battery and solar panel. \$\endgroup\$ – Passerby Jan 22 '14 at 3:21
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    \$\begingroup\$ Also, forget about the inverter. Changing 10~14v Dc to 120v Ac just to use a 120v to 5v AC to DC adaptor is like paying someone a dollar to change your Ten dollar bill to singles, then paying someone else another dollar to change those singles for a fiver. Just get a high powered iPad car 12v to 5v adaptor. They should be able to produce up to 2.1A if needed (at least if you don't get bootleg crap. It happens.) \$\endgroup\$ – Passerby Jan 22 '14 at 3:26
  • \$\begingroup\$ @Passerby Point taken. I have no idea what I would be looking for regarding a linear regulator, but I was able to confirm that it does in fact draw nearly the full power posted. When it was idle and merely recording, it floated around 1.5, but when accessed remotely via their web interface it rose to 2. When accessed, the camera can zoom, switch lighting correction, etc., which is why it (I assume) consumes more power. \$\endgroup\$ – emsoff Jan 22 '14 at 18:30
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Use a buck converter as others have recommended. Car adapter to USB will work. This reduces the cameras current draw from the battery down to about 1 Amp. (5V*2A = 10W = 12V*0.8A) You must upgrade the battery though. AGM will give you longer life than regular sealed lead acid. 12aH is not enough as this only gives you 12 hours of run time when the sun goes down which means you will lose power on any rainy or cloudy day. You can get a 40Ah AGM battery for about $100. A 50W panel is probably passable with 6 hours of sun per day. 50W - 10W camera = 40W * 6h sun = 240Wh vs 24h day - 6h sun = 18h night * 10w camera = 180wH night usage. This means you gain about 60wH per day under good conditions. 100W panel would be preferred though if you have the space.

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    \$\begingroup\$ hour = lowercase h. Watt = capital W. Please be consistent. \$\endgroup\$ – winny Apr 17 '18 at 8:20
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In order to waste power on AC/DC and DC/AC conversions forget about using an invertor and DropCam's power supply.

Instead you can use a solar panel designed for charging phones (at least a 40W one) and connect that to a battery bank wich can be both charged and discharged.

Most battery banks can't be charged and discharged at the same time but for example, TeckNet PozerZen advertises that it can work like that.

Those solar panels that are ~20W designed for charging phones are NOT enough for this application.

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