Calculating power needed for IP cameras

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sealtech101
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Joined: Tue Apr 14, 2015 5:16 pm

Calculating power needed for IP cameras

Post by sealtech101 » Tue Apr 14, 2015 6:14 pm

Hello, I'm trying to setup some IP cameras. I plan to have 3 on one pole. I'm wanting to have a system that never goes without power. 3 avtech IP cameras 10w ea., and a trasnmitter ( i Dont know watts on it will post later). Can someone walk me through the calculation for a 3 day battery back up with a solar panel that can recharge batteries in one day. Shortest day here is 4.5 hours of sunlight. North Mississippi. Thanks

techman
Site Admin
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Joined: Thu Dec 22, 2011 11:49 am

Re: Calculating power needed for IP cameras

Post by techman » Thu Apr 23, 2015 8:20 am

Sorry for taking so long to get to you. Been crazy here with the server migration.

Ok, lets put things down here so I can keep track.

30 watts for the cameras. Let say another 10-15 for the transmitter. Make it an even 50 for simplicity.

3 days and 4.5 hours of day light.

50 watts x 24 hours = 1200 watts per day.

1200 watts x 3 days = 3600 watts total reserve capacity.


You need about 300 AH of battery capacity. More is better to prolong battery life.

You need to recharge those batteries in a day so you need 300 amps in a 4.5 hour period - worst case.

300 amps divided by 4.5 day light hours = 66.7 amps input.
66.7 x 12.5 volt battery = 833 watts of solar panels.

You need about 800 watts of solar panels.

Now you can probably get by with a bit less solar because even on a cloudy day you will be pulling in some solar power.

Hope this helps

hazzic
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Joined: Tue Feb 03, 2015 12:02 pm

Re: Calculating power needed for IP cameras

Post by hazzic » Mon Apr 27, 2015 6:07 pm

Bang on, except it takes about 15 - 20% more energy to recharge a battery due to internal resistance, internal losses, and heat. So if you pull out it's full 300 AH capacity, expect to put 360 Amps back in over 4.5 hours for a full charge.

JimW
Posts: 36
Joined: Tue Feb 10, 2015 2:41 pm
Location: Oklahoma

Re: Calculating power needed for IP cameras

Post by JimW » Tue Apr 28, 2015 10:50 am

hazzic - that reminds me of a youtube video I watched where the person was showing how to set up a solar power system. One of the comments was from a lady that had a 100 watt panel and she wanted to know what size inverter she needed. Huh??? That's kinda like "how big is big?". She could run a 2kw inverter, for a very short time! Or she could run a 50 to 75 watt inverter and on a sunny day the solar panels would charge the battery for some night usage. That would allow her to run 2 or 3 15 watt CFL lights. But! Why not go to 12 volt CFL lights and avoid the power loss in an inverter?
Seems a lot of people are in the dark about solar power. It's great for spot applications, but it ain't likely to fully power your house unless you got lots and lots of money, or cut way back on your electricity dependency!
I use my 45 watt panel to charge a 12 volt battery that I run my 2 meter ham radio and my HF ham radio on. And I don't make long "rag chews" on either. I do use the HF for SWL and even limit that. Maybe if I get another battery and another 45 watts of panels I would use them more. Oh, and I do have a 300 watt inverter that I use only when there is an extended power failure in my area.

techman
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Joined: Thu Dec 22, 2011 11:49 am

Re: Calculating power needed for IP cameras

Post by techman » Thu May 21, 2015 10:32 am

Very true Jim. The real numbers on solar panels are pretty sorry with smaller systems. I should know.

You can get by with reduced power usage as I am. I use a laptop and modem on AC power. DC powers my LED lights intermittently but for the most part I use a solar powered LED light inside for evening usage. This is charged outside during the day and brought inside for evenings. I get about 2 to 3 evenings per charge so it works out nicely.

I am going to be doing a full review on the lights and portable solar panel soon. It is the SunJack kit I got.

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