Proposed Solar Wireless Surveillance System

[Sunking]

First you do not need to calculate battery Amp Hours as it is meaningless and just the final result of calculations.

Second where are you coming up with 5.5 Sun Hours? For a battery system demands you use the shortest Sun Hour Month

You panel wattage with 5.5 Sun Hours is going to result in a panel wattage to small to effectively charge the battery. Batteries require at least a C/12 charge current, and C/10 is perfect. So you calculated 108 Watt Hours a day which means you need a battery with a capacity of 5 x 108 AH = 525 Watt Hours. As 12 volts requires a 525 wh / 12 volts = 43 AH battery, lets call it 50 AH @ 12 volts. .

OK if you really had 5.5 Sun Hours to generate 108 wh per day with:


MPPT Charger is [108 wh x 1.5] / 5.5 SH = 30 watts.
PWM Charge Controller [108 wh x 2] / 5.5 = 40 watts

Problem is a 30 watt MPPT or 40 Watt PWM system only deliver 2.5 amps of charge current. 2.5 amps of charge current is only 50 AH / 2.5 Ah is only a C/25 charge rate which is way too low. You need 5 amps. To get 5 amps of charge current means you need either a 60 watt MPPT system or 80 watt PWM system. If it were me I would use a 100 watt panel with a 10 amp PWM charge controller and call it done. With a 100 watt PWMsystem you can even move up to a 60 AH battery.

Forget Peukert in your application as your discharge rate is well below C/20

[DanKegel]

That's an interesting application. Can you give exact part numbers? I'd love to hear how it works out.
(And SunKing's right -- in winter, I've seen long runs of ~3 'sun hours' per day. Get that bigger panel he recommends.)

(Also, I'm skeptical that wireless is a good method for getting video out of security cameras.
Are you quite sure you can't run a cat5e cable to each camera? Using Power over Ethernet means not having to run a separate power cable...
and the video is a lot better with netcams than with old analog ones, compare
old analog cameras http://kegel.com/crimes/graffiti-cameras.html
with new network cameras, http://kegel.com/linux/trendnet-tv-ip311pi/
The old ones aren't usable for identifying faces or license plates at a distance, but the new ones are.)

[RogerRetro]

Thanks for your quick reply...
I had found similar information to what you mention, and the panel will be oriented 170 degrees (from true north), at a vertical angle of 52 degrees, clear of shadows.
Thanks,
Roger

[sensij]

Is the solar panel powering the camera mounted south facing, at least 40 deg tilt, no shade and a clear view of the horizon? If not, your sun-hours estimate may be too high. If you haven't already, check out PVWatts (seems to be down at the moment, but is normally reliable), you can test different orientations. It will show average monthly insolation, and let you download the hourly breakdown as well. The model assumes "typical" weather, so actual weather will clearly vary, but it gives you an idea of what to expect. Sources of shade need to be considered separately.

Since your load is fixed, you may want to tilt the panel even more vertically, perhaps 50 deg or more, to improve the winter generation at the expense of summer, when the excess is less likely to be needed.

[RogerRetro]

Hope this is the correct section for this post...
I have done some research on building a single camera outside wireless solar powered setup for my house.
I would appreciate a sanity check on the following setup, as this is my first try, and I may very well not have it all figured out correctly. Any comments or advise appreciated.
Thanks,
Roger

Fremont, CA average sunlight hours = 5.5/day.
50W solar panel = 2.8A x 5.5 hrs. sun = 15Ah/day. 15A x 12V = 185Wh/day.
One 5V 4.5W PT Camera, running 24Hr/day, powered by a 12V/5V DC-DC Converter
Load – 4.5W x 24Hr = 108Wh/day@12V DC
Consumption – Ah/day = 108Wh/12V = 9Ah/day + Charging losses – 10% = 10Ah/day
Solar Ah required – 10Ah/5.5Hr @ min sun = 1.8A (min. for solar panel load in winter months)
50 Watt solar panel – optimum rated current = 2.8A
Battery – back-up power required ~4days, x 10Ah/day = 40Ah over 4 days = 96Hr
50Ah – Peukert discharge to 50% = 103Hr@0.375A = 4.3days
Panel orientation - 170° (from true north), vertical angle 52°, clear of shadows.