Best outdoor power source?

[rea5245]

Hi. I'd like some advice on what power source to use for an IP camera I want to put in a birdhouse.

The camera uses a USB jack for power and consumes about 0.3A. It needs to be set up through the winter, in cold New Hampshire. I'm hoping for owls, who stay here all year.

I could use a USB battery pack.

Or I could use an off-the-shelf "power station", like they sell for campers. They include USB outlets and 120V AC outlets, so they have stuff I don't need. They can get expensive, though there are cheap (less than $150) options that might be good enough.

Or I could make a DIY solution with lead acid batteries, 6V or 12V, and a buck converter to bring it down to 5V.

All of these would need to be sheltered from the weather, and all could be augmented with a solar panel, which might reduce how often I need to bring them inside to recharge them.

Any thoughts about which is best?

Thank you,
   Bob

[globoy]

Bob,

I designed a solar MPPT charger, designed for lead acid batteries, that might be a fit.  You'd have to create the shelters and - most importantly - size the panel and batteries to match you load.  I think lead acid batteries are best for most outdoor applications because of their operating temperature range.

https://www.tindie.com/products/globoy/mppt-solar-charger-for-intelligent-devices/?pt=ac_prod_search

Even if my charger isn't of interest, you should read the appendix in its manual that talks about sizing the system.  I think most people tend to underestimate the size of battery and panels they will need for reliable 24/7 operation - especially in winter which, in the northern hemisphere, is a very low solar production time.

0.3A @ 5V -> 1.5W x 24 hours means you're going to need about 36W of energy per day.  Since your camera is powered from a 5V supply then you'd have a DC-DC stepping down the nom 12V to 5V.  It has an efficiency rating so if you assume that to be 90% then you'll need about 3.3A from the 12V battery over the course of a day.  If you didn't want to fully discharge your battery to give it the longest service life then you'll need to oversize it to something like 12-15 Ah size.

Your solar panel, ideally, has to provide at least that much energy every day plus account for inefficiencies in the charge process and the battery chemistry itself.  Say you have to provide 4-5A (~50-65W) a day.  Solar panels need good sunlight to really produce power so you have to position your panel for maximum light.  Depending on the location this may vary wildly (from only a couple to several hours per day).  Usually you oversize the panel to help day with less than ideal sun days.  In this application I think a 30-40W panel would work.

In addition to my charger - which, of course, I'm proud of - and designed to be able to provide lots of data about how well the charging system was operating, there are a lot of cheap Chinese chargers out there that will also charge a 12V battery.  The same ideas in selecting batteries and panels apply.

Anyway, I hope this at least has given you some food for thought.

[rea5245]

I'd take a very skeptical eye about reliability, electrical / fire safety, etc. etc. since a LOT of "popular consumer electronics" are just horrible in those regards.

The question is not whether they're reliable and safe; the question is whether they're more reliable and safe than something I assemble myself.

[free_electron]

nuclear fusion. clean , renewable and readily available on average 12 hours a day. store some for use during nighttime when the reactor is on the other side of the planet.

[nightfire]

I also would opt for lead-based batteries, especially the AGM types (sealed) are quite nice, you can get them nearly everywhere, and the characteristics are well known.
A housing is mandatory in my opinion, to conceal the innards, provide isolation in winter and protect against angry birds.
With the voltage of a lead battery, some mounting position a few steps away from the nest would also be possible, to allow for the voltage drop along a long line to the nest.

[BrokenYugo]

Otherwise you can get low voltage "landscape light" 18/2 or 16/2 weatherproof outdoor direct burial cable and run 5V or 12V or whatever over it up to several amperes if needed and that comes in rolls 100, 250, 500ft or whatever, home depot, amazon, etc.  2-wires in a zip pair cable.   You typically hook that to a UL / ETL or similar rated limited energy isolated low voltage (e.g. 12VAC or 12VDC output as a common example) power supply that itself gets powered from AC mains and you connect your landscape lights or whatever to that.  So obviously if you have a safe isolated 5-12VDC supply you could hook it up over a long distance with that kind of cable from either a battery supply or an isolated low voltage power supply for outdoor stuff.

That's what I was thinking, 12V DC supply at nearest convenient source of AC power, then send that out on cheap zip cord and regulate down to 5V DC at point of use. Unless it's so far out that the wire would be costlier than a decent solar setup, though I would assume it isn't very far with an IP camera.

[strawberry]

NiMH cells
thermal insulation