battery powered wrt54g

Discussion in 'Modding Forum' started by jagboy, May 15, 2005.

  1. jagboy

    jagboy Network Guru Member

  2. gotamd

    gotamd Network Guru Member

    That's pretty cool, though I don't know how useful it'd actually be.
  3. jagboy

    jagboy Network Guru Member

    but hey it is a cool mod. might not the best solution but it is cool.
  4. RoundSparrow

    RoundSparrow Network Guru Member

    Be careful -without a low voltage disconnect circuit... when the battery getsweak the volts drop as amps will climb to infinity and burn out the power module on the board.

    I know, I did it :)

    The only affordable LVD I have found is plans to build your own... no one seems to have them pre-made for under $25.
  5. g412b

    g412b Network Guru Member

    Ehm does one of the basic elektricity laws like
    I=U/R says something to you ?

    Its not possible that amps rise when voltage drops ...
  6. davidsonf

    davidsonf Network Guru Member

    The WRT54G(S), and probably other Linksys models, can in fact run on as little as about 3.5 VDC. Lower than that and... no they will not burn out due to infinite amps! The actual operating voltage is 3.3 VDC, and the power supply requires something slightly higher than that. Lower than about 3.5 VDC and it will just drop out.

    They can also run on perhaps something as high as 18-20 VDC.

    The current at 12 VDC is about .45 amps, or roughly 5.4 Watts. At 6 VDC it will draw about twice the current, and at 18 volts will draw significantly less.

    Note that 1 Amp at 6 volts means no you are not going to get much life out of even D cells, never mind anything smaller! Think in terms of at least a little six volt lead-acid rechargable for a motorcycle, or something of similar size. Obviously it will work very nicely connected directly to a 12 VDC car battery too.
  7. davidsonf

    davidsonf Network Guru Member

  8. jagboy

    jagboy Network Guru Member

    has anyone tried this since the thread started
  9. davidsonf

    davidsonf Network Guru Member

    Tried what, running one on too high a voltage to see if the capacitors will explode???


    Running one from a variable DC power supply and measuring the current at different voltages? Yes. Jeff Liebermann and I were discussing this topic on the Usenet newsgroup alt.internet.wireless at the end of January and
    early February of this year. Jeff whipped out a lab supply and attached it to a WRT54G v1.1, and posted these results:
    >   Volts  Amps   Watts (receive)
    >   20.0   0.26    5.2
    >   15.0   0.35    5.4
    >   12.0   0.45    5.4
    >   10.0   0.56    5.6
    >     8.0   0.70    5.6
    >     7.0   0.80    5.6
    >     6.0   0.95    5.7
    >     5.0   1.2      6.0
    He said he could not go lower than 5 V because his supply limited at 1.2A of current. He did not attempt to cause the unit to transmit to see how much additional power that required, but we both agree that it would not be substantial.
  10. jagboy

    jagboy Network Guru Member

    thanks for the stats
  11. kioan

    kioan Guest

  12. SimonMackay

    SimonMackay Network Guru Member

    For battery-operated Linksys routers, I would consider looking towards use of sealed lead-acid batteries. Some electronics stores sell a 6-volt SLA which fits in one of those Eveready "Dolphin" lanterns. They are charged off a special sealed-lead-acid charger which you would be able to get from these stores.

    If the Linksys router or access point is of recent manufacture, they will most likely be designed to work on a 12-volt supply. Here, you will have a wider option. You may try "security-alarm" batteries, which are available at nearly every electronics store or security-alarm specialist. Here, these stores may offer plug-in chargers for these batteries. You could charge them up in a "standby" UPS for example.

    With regards,

    Simon Mackay
  13. Anonymous

    Anonymous Guest

    SLA Supply

    Ask me nicely enough and I'll post a schematic for a periodic charger that will switch on when battery drops to 11 volt, and charge it to 13.8 volt and switch off.
  14. zgamer

    zgamer Network Guru Member

    The battery operated wrt's would be more useful if they were paired up with a bit more complex system where the wrt could be powered upto 24 hours off batteries and then have the batteries being solar charged during the day providing a wrt that could function as a true wireless repeater.
  15. schembo2000

    schembo2000 Network Guru Member

    why not just use power over ethernet????
  16. crawdaddy

    crawdaddy Network Guru Member

    I'm an alarm technician, and as such, I always carry a spare alarm battery around in the trunk of my car. It's a 12 volt 7 amp hour battery, which I'm estimating would last me 10-12 hours. Of course, please correct me if I'm wrong, as I didn't do the calcualations exactly right I think...
  17. crawdaddy

    crawdaddy Network Guru Member

    I know I probably shouldn't be, but for some reason I am captivated by the whole bettery powered WRT idea. Surfing the net, I found this solar panel:

    The 7 watt model, with a modest price and an acceptable size, puts out 7 watts, which is more than enough to power the WRT and recharge an alarm battery, which could last through the night. This means that if you can find a spot to put a WRT and the reasonably sized solar panel (car maybe), you can run a router, that could do WDS or some other duty, with no need for a power plugin. It would be completley self-sufficient. Ok, enough of my stupid rantings...
  18. jagboy

    jagboy Network Guru Member

    i think that this would be possible. but i dont know if the solar panels can regulate them selfs, like if there is a day with a lot of sun will the solar panel excede the 7 watts that is puts out.
  19. t4thfavor

    t4thfavor Network Guru Member

    i have this working.

    i cut off the end of a spare power supply and wired it up to a cig lighter plug (for car) i have a battery in a bag (for a camera) 12v/12Amp/hr that accepts the cig plug. i have also experimented with low cost solar mods. they will work if the load does not get too big at night and the sun comes out during the day.

    i live in mid michigan and that doesnt happen very often.(dark all the time)

    p.s. Sorry to revive this thread so long after...
  20. Cenreyn79

    Cenreyn79 Network Guru Member

    There are 2 IC's (uc8 and uc10) on the board that follow the ba1 and ba2 slots. these are made by anachip and from the documentation provided by the company, these IC's can hold anywhere from +1.23v DC to 18v DC with a possible 2A output load.
  21. crawdaddy

    crawdaddy Network Guru Member

    With my alarm battery (12v 7ah), I can run a router for 1.5-2 days, oddly enough about the same runtime of a burglar alarm on the same battery. To charge that battery, I use a 1 amp 12v power supply I have. With it, it takes about 1-2 hours to bring the battery back to full charge, with no load. I would suspect that even with a solar panel that provides .5 amps, would be able to charge the battery with the load of the router in 5-6 hours. Easily doable most anywhere in the country I would think.
  22. kc2dqp

    kc2dqp Networkin' Nut Member

    Hey guys..

    This question I think should go here, but I am not sure. I've been hunting for this info about this issue, but can't seem to find it anywhere. I saw this on a website that would REALLY work well for my application. I would like to power my WRT54-G V.8 via batteries and have a solar cell recharge the batteries so I can check my email from my iPod/laptop while on lunch at work.

    Now, before you tell me it shouldn't be done with this model, I know, you can't remove the antennas. I have this all set.

    What I don't have and do need desperately is how wire the battery holder (a pos. wire and a neg. wire) to the solar cell (a pos. wire and a neg. wire) and most important of all, where on the board to solider them to. I was following a PDF file of a guy who did just what I am trying to accomplish, however, the photos are horrible and the writeup does not explain anything about wiring.

    So my question is this, If I connect the battery holder, and solar cell together (pos/pos, neg/neg) where do I attach them to the router board? Obviously where the wall-wart power adapter goes, but is this something that will work properly? anyone have any insight into this? any help?

    I've got this setup in a small lunchbox
    I've put a heatsink on the broadcomm chip
    I've flashed the router with WW-DRT (latest update)
    I've got all the PROPER voltage and rechargable batteries

    The one thing I don't have is the best way to get this together and working properly.....

    Please help... :)

    (if anyone is interested, once I get it rocking and rolling, I'll post my pics and write up on it)
  23. Jordan Stovall

    Jordan Stovall Reformed Router Member

    Hey I did this! I'm using a big 6v battery and a couple of bigger antennas that i bought at radioshack. I'm using it as a mobile repeater so i can go to some place and find the best signal end boost it. If anyone is still following this thread feel free to message or email me with questions!
  24. badassz34

    badassz34 LI Guru Member

    Way to bring out the dead! I've run a WRT54G from 12V SLAs as well as run one directly from a cig lighter outlet in my car. Runs like a champ either way. Actually, in my last apartment (a duplex) I put two 50W PV panels out and used those to charge a pair of 12V deep cycle marines batts, with those providing power to the WRT54G, an NSLU2 (with 2 1TB WD externals), and a Vonage adapter. My home network was totally off-grid and it worked pretty well, except that during the late fall through early spring I had to put a power-chair charger on a timer to top the batts off for 3-4 hours each night. Put the batteries in series for 24V and used a pair of AnyVolt Micro convertors to supply a 5v and a 12v bus, which fed the devices. Because I was on cable I had internet when the neighborhood didn't have power even. It was pretty pimp as I could still watch the radar when storms rolled through and knocked the town's power grid offline.
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