Question

System · April 2007

Hi New to Solar power , I have a 2.4 ghz wireless camera and wireless receiver, I would like to hook up a solar power panel or charger panel to the 2.4 ghz camera to where it will run during the day and also charge the battery the camera runs on either 9 volt or 12 volt connection.

I have a 9 volt solar battery charger that charges by rechargeable battery but don't know how to hook up this charger to the rechargeable battery to keep the wireless camera running, and help would be appreciated.

niel · April 2007

Re: Question

odds are that you won't be able to just put that to your camera and transmitter due to no regulator circuit in that solar charger. many solar chargers out there today are simply many smaller seriesed solar cells that could far exceed the voltage that would be safe for the batteries and electronics involved to work at without damage. there is most likely no protection from a battery discharging back through that same mini pv panel during those not so sunny nights either. the simplist way, if you are so inclined, would be to learn to build a regulator for it. i don't recommend this for most people to do without some prior knowledge of electronics and despite the claims of many of these solar chargers, they are essentially incomplete and could cause harm to whatever they are connected to and that includes rechargeable batteries. some people have even adapted old computer pwm power supplies, but again you'd have to know what it is you are doing. i know of one who has used solar on video cameras/transmitters and that is arcandspark, but getting advice from him will not be sufficient if you don't understand what he has done or is talking about.
if you have limited electronics knowledge i'll give you the lead by saying a regulator ic. if that doesn't give you your answer then you don't have enough knowledge to do it in most cases.

crewzer · April 2007

Re: Question

“… I have a 2.4 ghz wireless camera and wireless receiver, I would like to hook up a solar power panel or charger panel to the 2.4 ghz camera to where it will run during the day and also charge the battery the camera runs on either 9 volt or 12 volt connection.

I have a 9 volt solar battery charger that charges by rechargeable battery but don't know how to hook up this charger to the rechargeable battery to keep the wireless camera running…”

Sounds like a fun project. However, you’ll need to know more about the camera’s daily energy requirement, the 9V solar battery charger’s specifications, and your local insolation data to determine if this will work. “Run(ning) the camera during the day” adds another level of complication, as the system will need a timer or light sensor.

Check this Google search string for general info.

This site looks interesting: http://ideas.4brad.com/archives/000096.html

Another solution might be to cannibalize a solar powered light and use it to power the camera during the day.

Finally, you could look into a small "12 V" PV module, a small 12 V AGM (sealed VRLA) battery and a controller like this one to build a reliable system from scratch. This controller could operate a relay to turn the camera on during the day and off at night.

HTH,
Jim / crewzer

System2 · April 2007

Re: Question

i have a little xantrex c12 controller that also has timed and day/evening load control, designed for small systems, very similar to the morning start crewzer links to, im not sure how they compare costwise but its another option..

System2 · April 2007

Re: Question

I know in the hardware sotres there are alot of solar lights for the garden and walkways can a person use these as solar panels and hook up the wirless camera . Has anyone experimented with these

crewzer · April 2007

Re: Question

solar lights for the garden and walkways ... Has anyone experimented with these...

Check here: http://www.intermatic.com/Default.asp?action=div&did=2

I have a set of these lamps: http://www.intermatic.com/Default.asp?action=prod&pid=9280&did=2&cid=49&sid=77 They're 3.6 V.

HTH,
Jim / crewzer

niel · April 2007

Re: Question

most of those cheap solar lights that are usually on walkways do not have regulators either and are far too low in voltage for your application. even the one jim points out would be throwing good money after bad as it is for a 6v battery and light. if a c12 can regulate to about 9v then you could use it, but i don't believe that controller, or most controllers for that matter, are made to work at 9v so this would be custom made for this. most cameras work in the 100-250ma range and i believe that's also true of the transmitter and receiver. the batteries would be basically for the time periods of no sun and must not be fully depleted at the end of 24hrs so you would have to add all of the power requirements together and multiply that by 24hrs plus about another 10%-20% or so for charging inefficiencies for your total power needs in a day and i seriously doubt that the small pv panel you have can fulfill this requirement as it would only have up to about 5hrs of time to deliver the power that would be needed in 24hrs. don't forget too that many days have clouds so it is good to feed the batteries some extra power from pv with enough battery capacity to run for around 3 days. that figure is the average autonomy we use and some areas may typically need more if it is an area that can exceed that time with cloud cover.
jim,
congrats on the solar shogun statis.

crewzer · April 2007

Re: Question

jim,
congrats on the solar shogun statis.

Thanks!
Jim / crewzer

System2 · April 2007

Re: Question

Thanks Crewzer and everyone else who responded I appriciate the information CrewzerI like the idea of a controller like the one in the link you posted from Sunlight products. My question is then you need a controller to regulate how much the sun can charge the battery and also the controller runs the camera, but how does a person find out what size of Solar Panel to use is there a program that can calculate what size to buy.

Last but not least would radio shack handle these controllers , and how much do these run in price.

crewzer · April 2007

Re: Question

Glad to help! However, I'm concerned that this project may a bit more costly than you envisioned.

I don’t believe the Morningstar controllers are available from RS. However, Northern Arizona Wind and Sun, this forum’s sponsor, sells the full line at what appears to be very competitive prices. See: http://store.solar-electric.com/mochco.html

There are several PV sizing tools available on the WWW. I prefer to run the calculations myself. Assuming your wireless camera and a small relay requires 12 V x 200 mA for 12 hours/day, that’s 12 hrs x 200 mA = 2.4 Ah/day. Assuming average insolation of at least 4 hours/day and 98% coulombic battery efficiency (Ah out/Ah in for an AGM battery), you’ll need a PV module rated at (2.4 Ah/day /98%) / 4 hrs/day = 0.61 A x ~17 V = ~10 W.

Here’s a link to a 10 W PV module from NAWS: http://store.solar-electric.com/poup10wa12vo.html

Your requirements may be different, so feel free to plug your variables into the calculations above.

Allowing for 3 days of autonomy (no significant Sun), a 25% cold ambient temperature correction, and a maximum 50% discharge, you’ll need a small 12 V AGM battery rated at 2.4 Ah/day x 3 days x 125% / 50% = 18 Ah. These sorts of batteries are typically available from local battery stores. See: http://www.batterymart.com/p-12v-18ah-sealed-lead-acid-battery-1.html

HTH,
Jim / crewzer

niel · April 2007

Re: Question

jim,
what advice did you give gdgros for going from 12v down to the 9v that is needed? he cannot have the camera or transmitter/receiver subjected to 12+v. aside from a 3 terminal ic regulator the only other easy way would be to drop the voltage in about .5v steps with diodes seriesed and rated to handle his total current draw.

crewzer · April 2007

Re: Question

niel,

I didn't address the 9V issue, as gdgros' initial post says that the "...camera runs on either 9 volt or 12 volt connection". But, considering that the battery will charge at ~14.4 V during the day while the camera is operating, that may be too high a voltage for the camera.

(gdgros: You need to check the camera voltage specs).

If the battery charging voltage is too high for the camera, then you've brought up a good point. Considering the low current draw, a 7809(T) regulator (9V), a TO-220 heatsink, and a couple of small capacitors should do the trick. I would think that all of these items would be available from RS. If the 7809 is too hard to find, he might need an LM317 plus a few extra parts instead.

A 7812 (12 V) regulator probably won't work due to the high minimum Vin requirement (~14.6 V).

This is getting complicated! It might be easier/cheaper to just buy a solar powered wireless camera via the Google link above. In the end, it's gdgros' choice.

Regards,
Jim / crewzer

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