WRT54G with solar power

Discussion in 'Modding Forum' started by leenar, Jul 9, 2007.

  1. leenar

    leenar LI Guru Member

    I recently completed a tut on how to run WRT54G off a solar panel and a 12V battery. Mine is in an all-year-round outdoor application working as a repeater for the back yard.

    photovoltaic DIY power supply
  2. Disman_ca

    Disman_ca Super Moderator Staff Member Member

    Nice write up.
  3. Toxic

    Toxic Administrator Staff Member

    nice one! i'll move this to the modding forum. thx :thumbup:
  4. SlimJimE

    SlimJimE Network Guru Member

    What happens if your router only requires 5V?

    Would like to build something to put on a tower so I dont necessary need the switches. However, I am worried that if the sun does not come out and the battery drains what will be the concequences of running only at say 2V.
  5. t4thfavor

    t4thfavor Network Guru Member

    Depends, the wrt54g 1.0 ran on a 5v psu, the newer ones have a 12v psu and then convert internally to 5.0v. this means that the regulator inside will take care of the voltage drop(to a point). so you could run your 12v router on say 6v, but I would doubt a 5v one will run at 2v.
  6. SlimJimE

    SlimJimE Network Guru Member

    Well maybe I am misunderstanding to a degree. It looks like instead of using the PSU that you would normally plug in the wall you just plug 2 leads directly to the battery and the other end would be the special plug for your router. Running 12V to my 5V router is what I am trying to overcome. I thought my PSU is only providing my router with 5V and now in this setup I would be running 12V. That is 7V more that my router doesn't know what to do with and don't want to burn it up.

    Of course if I had a 12V router I would have no problem but this is not the issue. Now if I plugged in an AC/DC Converter I would be converting DC to AC than AC back to DC which probaly is not all that efficient.
  7. SlimJimE

    SlimJimE Network Guru Member

    leenar could you take a picture of the inside of your enclosure. Would like to see how you fit everything in your enclosure and possible install pictures.

    Very nice imformative review by the way.
  8. Slimey

    Slimey Network Guru Member

    yeah be careful not to try and run 5v routers off of 12v ;)
  9. leenar

    leenar LI Guru Member

    I'll post some outside photos. I don't have any installation pix other than the ones at my website. I will try to take a picture of the inside of the enclosure when I get a chance but it's a mess of wires. The enclosure is barely big enough to house a 12 7Ah battery so I didn't have a luxury of wiring it nicely.

    Now about your setup--

    Since your router requires 5V it would be the best to use a 6V battery instead of 12V like I did. You can find them online like at this place http://www.batterymart.com/p-6v-12ah-sealed-lead-acid-battery.html

    Placing the box on a tower will require a weatherproof enclosure. Such boxes are sealed which technically is not the best thing for a lead acid battery. Although the batteries like the one I linked to are sealed and are not supposed to leak hydrogen you never know. There could be a bad battery. If you live in an area with freezing temperatures (which is another issue to deal with) the battery could crack and the explosive gas could leak. In a weatherproof enclosure the gas would be trapped and a short circuit could make the whole contraption explode.

    I don't think this scenario is likely but it is possible. My enclosure is not sealed and I also cut some vent holes on top as a preventive measure. With all this said, if you leave in a rural area, if the tower is away from anything that could be damaged by (unwanted) explosion, if there is no danger of fire, I'd stick it in a sealed enclosure and assume the risk.

    Also, before you mount anything on the tower test it. Run it for weeks to see if your solar panel will provide enough charge to get the battery going. My setup is such that I can't run the router 24/7 because the solar panel's output is low. It still meets my requirements but I can't keep it on all the time.
  10. SlimJimE

    SlimJimE Network Guru Member

    Leenar is your router stored inside the sealed enclosure as well? Where do you keep it at?

    In trying to decide which Solar panel would do the best job for 24/7 should I look at 3 watt. In your calculations you came to the conslusion that you need 2.88watt or more. Would a 6 watt be a better idea for say 12 hours of sunlight? Using the same router you hve

    On my version 2 wrt54g I get an ouput power of 1000mah @ 12V. It looks like I will be pulling 12 watts of power. Which in turn does not look like much battery time. 7 hours maybe. I also have a 5v but I have not looked at the maH to calculate.

    Thanks for your post.
  11. leenar

    leenar LI Guru Member

    No, it's not sealed. It's under a roof so it doesn't get wet. I attached some photos.

    A 3W panel could be OK. It should be able to power the router, howeverr not much juice will be left for charging the battery. If you want to run 24/7 you need at least twice as much. Also, there are things you don't control like cloudy days, dirt accumulation on the panel, etc.

    How do you get 1000mA on WRT54G? That's four times as much as what I measured on 2 different linksys routers. Mine draws 280mA I think.

    Attached Files:

  12. SlimJimE

    SlimJimE Network Guru Member

    I am just reading off what my PSU said. I guess that could be maximum but I am not really sure how to read how much it is actually pulling. WRT54G v2

    I see you have a stubby connected to your WRT54G. Are you using as a repeater? Are you able to utilize both antenna ports?
  13. leenar

    leenar LI Guru Member

    I see. PSUs are always able to provide more power than the device attached to them need. You can measure how much current your device draws with a multimeter.

    The WRT54G is used as a repeater. Both ports are working but it's really not designed to work with two different antennas so the speed suffers. WRT54G uses diversity mode and when you connect different antennas or directional antennas that cover separate radio cells the diversity circuitry gets all confused. There are more details on this and a guide on how to fix this problem at http://www.skifactz.com/wifi/wrt54g_repeater_improve.htm
  14. crawdaddy

    crawdaddy Network Guru Member

    ahah, I now see why you painted your AP white...to blend in with the patio! :) Good idea. I'm looking at setting up a bunch of these in a "forest" to provide wifi to a boy scout camp. I don't recall if you ever mentioned it, but what was the total cost of parts to complete this project. Also, I see you mounted your AP straight onto the rafter of the patio, how does moisture and other things (such as wasps, etc) affect it? I live in Louisiana, and our humidity never drops below 80%, so I'd be worried about corrosion of the circuits and just flat out water or rain getting on it. We have about 10 billion wasps that call the camp home. I also have a vandalism aspect to adress. I apologize if I'm asking an excessive amount of questions, I'm just trying to pick you brain for experience and knowledge. Thanks.
  15. leenar

    leenar LI Guru Member

    Get those boy scouts to paint the router with camouflage patterns. They'll love that project!

    It's very dry where I live. I haven't dealt with moisture. You can check Linksys operating environment specs for WRT54G. I don't know if they list relative humidity.

    The operating environment specs may not be the final word. If your humidity is outside of the range they list it doesn't necessarily mean the router will be unreliable. It may mean that they have only tested it in the given range. If you're outside the range it may work. You're on your own.

    Copper doesn't corrode. Or it does but not much. Besides there is a protective layer on PCBs so I don't think corrosion would be much of an issue. Maybe if you were close to the ocean where there is a lot of salt.

    Rain is a problem. I've seen DIY projects for WRT54G rainproof enclosures. Look around.

    Insects could be a problem. Wasps are kind of large, aren't they? I don't know that they can get inside. On my battery enclosure I covered the vent holes with screen door mesh so larger bugs can't get in. The worst that could happen with an insect is that they could short the 12V power (although I wonder if this is even realistic). If you put a fuse on the DC supply line that will keep your router safe and sound.

    A fuse will help in case excessive moisture shorts the power too. Good luck with the project.
  16. gatorback

    gatorback LI Guru Member

    I would consider using a 5 volt regulator that would meet the current requirements.

    Really nice writeup. Check out this clip of the family hardware store solar PV system:

  17. MAS3

    MAS3 LI Guru Member

    Some comments (if i may)

    Hi leenar, nice project !

    You took some stuff in consideration most people wouldn't even think of.
    One of them is the gas which possibly might occur on batery faillure.
    In order to get rid of those gasses, you mentioned ventilation holes on top of your casing.
    But this will not help you very much.
    By my experience, the gasses formed by the acid in accu's are heavier than air.
    That's the real danger with those gasses.
    As most people think gasses are always lighter than air and so will raise in plain air, this can be dangerous.
    A ventilation hole in top of some casing will not get rid of the explosive gasses, it wil rather be a nice way to completely fill your casing with this gas.

    So: drill some additional holes to really let the gas out.

    Furthermore you state that copper barely oxidises.
    This is not true, it oxidises ok.
    But what's worse, copper that has an electric charge oxidises very fast.
    This is caused by the cathalytic properties that such charge provide.
    This is part of the electrolysis process and needs exposed copper or any conductive material in oder to take place and getting moist on it will definatly get this going within 20 seconds.
    Wikipedia has a nice article on electrolysis which explains it all.
    As you stated correctly, most parts of copper is covered by some protective layer.
    But not the solder parts and these are affected by the very same effects.

    So i am not telling you you are really wrong, but one should take this posibility in consideration as well.

    Taking these things in consideration i'd suggest two casings, one for the battery and a sealed one for the router.
    If this last one is made of some plastic, the antenna(s) can be inside as well.
  18. crawdaddy

    crawdaddy Network Guru Member

    I do see where you're going with this mas3, however, I think the resolution to that would be to spray all components with exposed copper with a laquer or something similar so that they will be covered, yet easily accessed if troubleshooting is required. That should keep it from corroding...
  19. lagunabeachcomputer

    lagunabeachcomputer Serious Server Member

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