Considering Putting Together Off-Grid Security Camera System

**SunEagle** · 11-14-2016, 03:31 PM

Greg. While I have not performed the calculations for your system I will hazard a guess and say you are probably correct and very close to your estimate that it will be a close match to just have the electric company run power to your cabin.

When it comes to even a small off grid solar/battery system that has to run 24/7/365 you will find out the the cost starts to add up vertically and running that extension cord the length of 2 football fields will look cheap.

I will also add that especially in a state like Texas where the electric rates should stay low the cost of replacing those batteries every 3 to 4 years will keep going up making connection to the grid a smart decision.

Something you can consider is that once you get the grid out to your cabin you now have the option of installing a grid tie solar pv system which may pay for itself sometime in the future. Again it is not a short term investment but it could be something to consider somewhere down the road.

**inetdog** · 11-14-2016, 03:52 PM

If you do not also install an Internet connection to allow the video to be sent offsite, you will have to do a very good job of hiding and/or fortifying the DVRs to keep the next thief from just stealing the surveillance system as part of their visit.

You recognize this, but there are at least two potential problems with your solution:
1. The energy cost of the constant network connection, and
2. The simplicity of bringing in a cell phone jammer to prevent the data from getting to the cloud in real time.

**DanKegel** · 11-14-2016, 05:52 PM

$5k is sounding like a bargain compared to $1k of batteries every few years.

How much would it cost to get a cable modem internet at your cabin?

**inetdog** · 11-14-2016, 06:01 PM

Originally posted by DanKegel

$5k is sounding like a bargain compared to $1k of batteries every few years.

How much would it cost to get a cable modem internet at your cabin?

If grid is not close, I would not expect cable to be there at all either. They typically follow the power infrastructure except where the density is high enough to justify underground.
Satellite is an option that would be harder to jam, but expensive and consuming more power.

**KMac** · 11-14-2016, 06:10 PM

There are cameras that don't need dvr and store images locally, allow upload on motion detect and login via cell service. Lowers your power needs considerably. Looking at Sharx cameras now myself using POE from batteries without need for inverter. Hence, just router w USB cell dongle and camera. Not as much as you might think. Lay out your car ulations for us to see.

**azdave** · 11-14-2016, 06:12 PM

Do you happen to have reliable cell phone service at the cabin? That opens up some possibilities for small standalone security systems like used at construction sites and such.

Alternativey, since I've found security video to not be that reliable to actually record intrusions and be able to read license plates or identify faces, how about having the "appearance" of a good security system in plain sight with official looking signs, cameras and other support items. Sometimes that is all it takes to make thieves move to another victim. Intruders won't know if it's actually recording or sending video to the cloud.

**DanKegel** · 11-14-2016, 06:21 PM

Originally posted by azdave

I've found security video to not be that reliable to actually record intrusions and be able to read license plates or identify faces

True! You need pretty high resolution to identify faces or license plates, especially from still frames. El cheapo systems didn't used to have enough resolution.

FWIW, a 3 megapixel Trendnet TV-IP311PI can resolve license plates at 50 feet at night head-on. Don't know about from the side.
Here's a picture: http://www.kegel.com/linux/trendnet-...0h27m18s22.png

**KMac** · 11-14-2016, 06:42 PM

Hikvision is another camera I've read good things about in your scenario. Read the specs on these. Again, native ddns to access camera directly or have it upload, or both. Images stored locally too, on camera SD card, so redundancy. No dvr. What, maybe 20-30 watts give or take? System you described seems bigger than that.

**foo1bar** · 11-14-2016, 06:43 PM

My guess is you're best off with either a trail-cam type setup (risk of that being stolen too, but possibly you can hide them well enough)
OR you go ahead and get electicity run to the location.
Which may be better option, since it probably makes your property worth more.

If you don't already have a good fence and gate, I'd look at doing that. Make it so someone has to cut a lock to be able to drive up to the building.

**SunEagle** · 11-14-2016, 09:05 PM

Maybe a combination of trail cameras, fences, and automatic flood lights to scare off anyone that gets close.

I also think that make self contained alert systems that can send a signal to a cell phone like the nest camera.

It all comes down to how much is the property worth that you are trying to protect and how much are you willing to spend to protect it.

A high end security camera system is not cheap and keeping it powered 24/7 will also be expensive. A fence with barbed wire, traps with bungee sticks and trip wires may be enough to deter thieves and a whole lot cheaper.

**solar pete** · 11-14-2016, 09:17 PM

...and claymores, dont forget the claymores

**KMac** · 11-15-2016, 12:01 AM

If you are wanting to do this solar powered security thing, I suspect you should think first of how low of wattage you could make it use. For example, all the components typically already run low voltage DC, which you have in the batteries. So figure how to skip the inverter from 24v DC to 120v AC and also don't use the adapters on each item that take it back from 120v AC down to the 5v DC most of them seem to require. Instead use some cheap little step down converter from 24v battery bank to what you need, and save the wattage of the inverter.

Then, on the camera sytem skip the dvr like mentioned above (some of the newer cameras store the images on-the-go in "edge" storage - camera based SD card). That saves more watts with no DVR.

Use power over Ethernet to get the signal from the camera to the router, and power from batteries to the camera.

Semi educated back of napkin ballpark follows: with each component you need there is maybe 5-10 watts being used, and so you might end up with 25-35 watts total. Over 24 hours that's 600 to 850 watts. So you would need to harvest, what, 900 to 1400 watts a day with all the solar PC system losses? In west Texas? How much sun isolation on an average day in the worst month? You can see the importance of avoiding burning every watt you can.

If you are at low end of estimate it would use only 600 watts per day, and you want to make sure it can last three cloudy days, you would triple that and want that total to be tolerable without damage to batteries. Maybe add a low voltage shutoff to protect them.

Figure three days no sun, 1800 watts used and not replaced, and you want to avoid draining the remaining below 50% in that time. Four 6v batteries with a a total of maybe 3600 watts in them should do it. That is what, 150Ah at 20HR rate? So, I am guessing a couple grid tie 250 watt panels and a decent mppt charge controller with right sized batteries would do it. Not $5,000.

Get precise on these ballpark figures using the "stickies" in the forum, work out the details, shop wisely for mid range products, and you might be pleasantly surprised.

There's that pesky cellular bill though, about $10/ month here, using your data plan. These cameras (or others like them) can be adjusted in sensitivity of motion detection, and you can typically decide to upload via ftp or automatically to your own dropbox or other online storage account. You can make them push email notifications to your phone with lower resolution and then login to the camera itself via ddns to watch or download the high resolution, saving cell phone data.

Yes, you would have to get precise on wattage of each component, and make compromises, but I think Nitin can be done.

Here is an added thought. Don't stop there - Get a charge controller big enough to expand, and skip 12v stuff (go 24v on panels and battery). You could then someday expand to say a system with 1kw panels, and 40 Ah batteries, and you've got power for lights, fans, or even a small 5-6,000 BTU window air.

But it might be easier to just run the power line.

**Greg Hamilton** · 11-15-2016, 12:29 AM

Okay, someone said to show my calculation, so have listed below. Please note the all caps note in Step #4, which is basically saying the web page I was looking at recommended a fudge factor of 2.0 here and I played with it till I ended up with only needing two batteries per system for two systems, not sure if I can really get away with this or not, but would save me about $250 if I can. The battery I am thinking about using is the EverStart Maxx Marine Battery, Group Size 29DC with 122 AH, which has a 2 year free replacement, which will be good since I plan on running this battery hard if I go through with this. Another concern I have is in Step #6 below where I end up with 1.04 as the number of 100W solar panels needed for each of two systems. I am hoping I can get away with just one. Another problem I am coming up with is the router(s). The two routers I purchased are both 5V dc. I need to find one that runs off of 12V dc and has a USB port for 3G/4G modem, but I have looked all over and cannot find one, so now wondering what kind of voltage divider circuit I can put together to put inline with the 5V dc router I already have. If I can get away with changing the fudge factor in Step #4 from 2 to 1.55 and if I can find a 12V router and if it does not add any significant power requirements that would create the need for additional batteries and/or panels, then I can shave off $650 from the previous battery projection of $1150 just by switching from Duracell batteries from Batteries Plus to Everstart Maxx batteries from Walmart, but that is a bunch of if's that I am not sure about.

With this huge drop in cost of batteries, that would bring it down to $925 (batteries=$500, panels=$216, mounting brackets=$108, charge controller=$50, installation tools & hardware=$51). Of course a lot of this is pie in the sky on my part and could be much more.

I appreciate everyone's input, I am still looking into the other camera options that were suggested to reduce my power needs, I spent all day on this today, will probably do same tomorrow. I liked the comments about the booby traps. Would be a lot easier to just move the deer blind a couple of hundred yards from the cabin and start hunting predators instead of deer, would not be such a technological challenge, but would create other challenges.

Calculations For Batteries & Solar Panels:

Step #1	Calculate the daily WattHour usage of each item.
	This is done by multiplying the item wattage by the number of hours used each day.

	Swann Professional HD Security System (SWDVK-443502)
	Have two separate systems, each has one DVR and 2 cameras, plan is to have separate solar system for each security
	system so no wires have to go between 2 buildings.

	Swann Scenario Calculations (per system):

	camera one	4	watts	times	24	hours	equals	96
	camera two	4	watts	times	24	hours	equals	96
	DVR	18	watts	times	24	hours	equals	432
	Total	26 watts					Total	624	Watt Hours	per security system

Step #2	Add up the WattHour results for all of your appliances. This will give you the total daily WattHours required.

	Total	624	Watt Hours	per security system

Step #3	Assume that you want at least 3 days of operation before the batteries need to be recharged.
	So you multiply the total daily WattHours by 3.
	In practice, you will only have to be concerned about this in bad weather or winter.

	Bad Weather Fudge Factor:
	624	watt hours times		3	equals	1872	watt hours

Step #4	Find the total battery capacity required by multiplying the 3 day WattHour figure by 2.
	This way, if you run for 3 days without recharging, you will only discharge the batteries to about 50% capacity.

	Don't Want To Discharge Batteries Below 50% Fudge Factor:

	1872	watt hours times		1.55	equals	2901.6	watt hours (Battery Capacity Needed)

	NOTE: PLAYED WITH THIS FUDGE FACTOR TO GET CLOSEST TO TWO BATTERIES BELOW WITHOUT EXCEEDING TWO.

Step #5	Calculate the size of the battery bank in AmpHours.
	This is figured by dividing the total battery capacity required (from step 4) by your system battery voltage,
	usually 12, 24, or 48 volts.

	2901.6
	---------	equals	241.8	Amp Hours		;	241.8	divided by battery AH rating of			122
	12
									equals	1.98	batteries
							SEE NOTE ABOVE ABOUT PLAYING WITH FUDGE FACTOR.

Step #6	Determine the number of solar panels you'll need.
	For this step you will divide your total daily WattHours by your solar panel wattage times the hours of sunshine.

	624	total daily watt hours divided by (				100	watt solar panels times hours of sunshine of			6	)

									Equals	1.04	100W
											Solar Panels
											THIS IS NOT VERY MUCH OVER ONE, SO HOPE I CAN GO WITH ONE SOLAR PANEL.

**KMac** · 11-15-2016, 12:45 AM

Okay now, lots of work there, but a few Comments:

1. how many hours of solar isolation (useable) in worst month? Surely not 6hours. even in TX. Look that number up. It's published somewhere online.

2. Why 12v? 24 is better for many reasons. Compare price if 100w 12v panel and a 200w grid tie 24v panel. Price per watt is not even close. I'd go with 24v. Same with batteries, if you can. Then read again my comments about a step down converter from 24v to the 5v or whatever components need. Adjust the voltage, not the router.