Where I live, short power cuts are fairly frequent and can be very irritating. I have also wanted to experiment with CCTV for some time. After experimenting with test UPS systems using cheap inverters and old car batteries I decided to scale it up.
When homes have an alarm system installed it usually contains a backup battery in case of power failure. These batteries need to be replaced every few years to ensure the system performs correctly.
The waste batteries are usually sold to scrap dealers for their lead content, but alarm installers are usually happy to give/sell them to you for an incredibly low price. We have picked up 7AH batteries for less than 50p each.
In this instructable I aim to show you how easy and cost effective it can be to "recycle" these for your own projects, such as a UPS/CCTV system.
The project was designed, tested and built by myself and Dom. We are fairly experienced with electronics and suggest that this project should only be undertaken if you have done all the appropriate research beforehand (also see safety disclaimer on step 2).

Step 1: Part 1 - Gather Parts

This instructible can be followed to the letter, or changed to suit your own needs if you wish to use other batteries etc.

We used:

8x 7AH Sealed Lead Acid batteries    -   £4       -     Alarm installation company
700w modified sine wave inverter      -   £25     -    Gumtree (classifed ads site)
Selection of wire, mostly mains flex   -   £0       -    Had this laying about at home
2x 8 way earth block                              -   £3.92  -    Toolstation
3 pole double throw 240v relay           -   £4        -     Ebay
2x 13A plugs                                           -  £0         -    Had these laying about at home
Double gang socket                              -  £0         -    Had this laying about at home

Extras for CCTV:
Old computer (Prusabox)                      -  £0         -   Came from a family member, saved from the tip!
RCA cable                                                -  £2         -   Ebay 
EasyCap                                                   -  £4         -  Ebay
IR Night Vision CCTV Camera             -  £9         -  Ebay
LAN Cable                                                -  £0         -    Had this laying about at home

Optional: Instructables T-Shirt for optimum DIY-ness
Very nice setup !<br /> There's just one slight improvement i'd suggest.<br /> When wiring such a battery bank in parallel, it's better to run the negative and positive wires in opposite directions.<br /> This distributes load better across the batteries.Otherwise the &quot;front&quot; one tends to work more than any other and will eventually fail earlier.<br /> ( Although this might not bea a significant concern since your setup doesn't power anything most of the time ).<br /> <br /> Great work!<br /> <img src="http://www.electricfence-online.co.uk/ishop/images/1047/ParallelBatteries.jpg" />
Thanks for the tip! <br />Will bear that in mind if we ever need to rewire the battery bank. Have pleanty of spare SLA's to drop in if one does fail though.
<p>I did this, but with a very important Step.</p><p>As I Noticed, all cameras &amp; DVR itself runs over 12VDC. I ran Heavy gauge Automotive wires to cameras &amp; DVR directly off battery (With fuses of course). That way you skip the power hungry inverter as well as stupid AC-DC transformers &amp; rectifier. The Efficiency of system goes up good 50~60%. Try it!</p>
Great post guys. I'm looking to build one of these in the next few weeks for a cctv system. I would also like to back up an internal light in the house do you know if this is possible using your system? Any advice would be greatly appreciated. Thank you.
If you've used linux before try Zone Minder http://www.zoneminder.com/ <br /> <br />a very powerful open source linux CCTV software. <br /> <br />With a extremely large range of features.
I am running Windows at the moment but i would like to give zoneminder a try, might set it up in a virtual machine and see what its like <br /> <br />Thanks for the interest <br />Chris
<p>Why not just try VLC player? as u r using a standard video device the EasyCap I think that should be a good enough software for your use.</p>
<p>Thanks for this, especially for the relay info.</p><p>Regarding your video software.</p><p>I use yaw cam, has quite a few nifty features like streaming, motion capture, etc. works with both USB and IP cameras. Have had issues though setting it up with DVR cards so not sure how easy it would be to use with EazyCap</p>
Did your inverter have an auto low-voltage shutoff? I need to find one that doesn't have that feature so I can get maximum output.
you could simplify this further and cut out the expense of a video capture card by simply using a usb webcam and an active usb extension if required tho webcams arnt usually waterproof but im sure you could quite easily make a waterproof enclosure. <br>the video from either cam set up could also be encoded with adobe flash media live encoder or windows media live encoder along with sound from a microphone if required and saved on your hard drive as well as being streamed online and viewed remotely via a website url, though for this you would need to purchace a domain and have some sort of server to service this which you could probably set up on your own pc and isp as the bandwidth draw for 1 viewer would only be small but if you paid for an external server you could also archive the stream remotely online so even if someone breaks in and steals your pc and all your survelance equipment you will still be able to recover the video evidence ;-) and you can check on your property anywhere in the world where you have an internet connection and with the correct set up you could even view it on your mobile phone. and of course anyone you give the url to could also check on your property and of course if you have multiple cams you could connect these to manycam and set the encoder up to stream from manycam and best of all all the software ive mentioned is free for personal use ;-) tho this does require some technical knowledge to set up but i could hook you up with a friend who could provide this service as well as a remote server and bandwidth ;-)
<br>I was considering building my very own version of this...a bit more simple... <br>I would use 8 standard car batteries + one 600w car dc-ac inverter. <br>If I were to use a 13w Walmart floodlight (apx $12) I would derive from this setup <br>(after rounding up...) up to 8 DAYS of continuous light. <br> <br>Assuming: amps = watts/ volts <br>Car battery = 12v <br>Inverter = 600w (max) <br>(600w/12v = 50amps) <br> <br>So, 50a distributed over 8 car batteries = 6.25 amps used per battery per hour. <br>(6.25ah/battery) <br>Each battery averages 40ah...so (40/6.25 = 6.4 hours of life at full power.) <br> <br>Now... if I use only 13w (1 LED floodlight)... <br>Car battery = 12v <br>inverter -&gt; lightbulb 13w <br>(13/12 = 1.08333 amps) <br>1.09a / 8 = 0.13541666ah/battery (rounding to 0.2 <br>Each battery averages 40ah...so (40/0.2 = 200 hours of life for the one floodlight.) <br>8 DAYS of constant on. (If u use a daylight sensor...16 days) <br> <br>so, theres the math...have fun!
......almost, dont forget if you are going to do the maths to include the efficiency of your inverter as inverters generally are about 80-90% efficient so your 200 hours would in reality be 160-180 hours or less if your inverter was less efficient, <br>probably of little consequence with a floodlight but could prove critical in some applications
impressive :-) 5 stars and a vote from me!
We have added a nice looking control panel for the system too: <br>http://www.youtube.com/watch?v=8PAhAZ1R-kU
I really like it - is your inverter running 24/7 or does it power on when the relay flips over? <br /> <br />One thought; many consumer electronics run on 12v. You can get a 12v psu for the computer, and you can run the camera(s) directly off the 12v bank. You can even add alternative energy (solar) to top off your batteries, so long as your trickle charger is appropriate. Saving the efficiency losses of the inverter is always a nice thing.
The inverter is powered at all times. On our <a href="http://www.youtube.com/watch?v=Phuvtr-_bQk" rel="nofollow">test version</a> using a 150w inverter we switched it using the relay but it took far too long to &quot;warm up&quot;.<br /> Yeah I like the sound of those PicoPSU's you can buy for DIY car-puters which accept a 12-24 volt input. Cost is the issue here, using an inverter also allows us to run anything we want.<br /> My Rayburn range cooker relies on an electronic ignition system even though the oven is gas fuelled so it would be handy to run that from the UPS too.<br /> Solar panels and wind turbines are great but also come with a high cost.<br /> Thanks for the comment<br /> Chris
I agree with frollard's thoughts about using a UPS. It's much simpler and effective. Solar panels would keep your system up 24/7, while its stated there are only have approx. 1 - 1.5 hours of run time. If you have an extended overnight outage or the like, you have a problem. <br /> <br />You could get away with a 50 watt solar panel to help extend the run time. It won't completely recharge the batteries, but it will slow the draw during the day. <br /> <br />Also (A last random note) that is one wierd looking plug outlet. That's not American, is it? Our plugs typically run at 120v. I don't know why they up the voltage. <br /> <br />Good instructable and good luck in the green tech contest!
I have a 12w solar panel for a boat/caravan I am tempted to wire in, but big solar panels are well over our budget! <br />Our inverter uses a standard UK socket, we use 240v here. The Inverter I pictured in the middle of the other two I believe has a universal style plug that will accept UK, US and European plugs.
Impressive work, congrats.
Thanks :)

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