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26 posts

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Topic # 66954 25-Aug-2010 22:45
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Putting aside inverters for a moment, does anyone know if anyone in NZ sells a router than can be powered directly from a 12v DC source (i.e. a boat battery)?

Cheers

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  Reply # 372897 25-Aug-2010 23:18
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Most of them have an external power supply. Just a matter of checking if it is a 12v one. wrt54gs has a 12v one stock but is ok with anything from a 5v one up to at least 16v since thats about the peak that my car sees.

edit: so did my asus 520gc - not the gu tho, as that needs 5v for its external USB interface.




Richard rich.ms



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  Reply # 372970 26-Aug-2010 08:44
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Forgive my ignorance, but I thought I needed something to convert the DC to the AC requirements of the router?  For instance, my router at home has a "5v AC" input.  Are you saying that the external power units actually convert 240v AC to arond 5-12v DC?

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  Reply # 372986 26-Aug-2010 09:26
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Hi, there are a few that take AC and have an internal rectifier, old dailup modems always did this, if thats the case then you could possibley bang 12VDC into it either polarity and it will work, just have to ensure that the regulators have enough heatsink to deal with the extra heat.

Most however take either 5VDC or 12VDC.

If it were me I would go for one that needs 5V, a lot take 5V and around 1-1.5Amps, then get a 12V-5V DC-DC converter to provide a clean 5V DC feed for it like this

http://www.jaycar.co.nz/productView.asp?ID=MP3046&CATID=24&form=CAT&SUBCATID=619

Cyril



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  Reply # 372989 26-Aug-2010 09:29
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Perfect - thanks.

...now I only need to hope my theory that a generic router will work rather than the $700 branded version the GPS company suggests....


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Master Geek


  Reply # 373000 26-Aug-2010 09:47
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Hi Trevor

I'm not quite sure what you are 'routing' but you might like to check whether it is actually a router you need or just an ethernet hub/switch. I know that some of the marine electronics are starting to use generic ethernet to connect their components but still try and sell you a highly expensive 'marinised' hub. As you no doubt know, every time something has marine in the label you add a zero!:-)

If it is just a hub/switch then I'm sure you will be able to find one that uses an external power supply with AC in and 12v DC out. If so... just make up a cable and plug it in. I've done this on my boat with a Combo TV/DVD player an it works perfectly.

Cheers

David

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  Reply # 373003 26-Aug-2010 09:50
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Hi, yes good point David, guess we should clarify what exactly you need, a router suggests it has an uplink WAN to the internet somewhere, somehow at sea, where as as David says do you infact just need LAN services (ie ethernet switch).

Cyril



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  Reply # 373021 26-Aug-2010 10:09
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Sorry - my bad.  It was only a switch. (I think I had the notion of "routing" data on the brain.) David - do you know off the top of your head what brand you used?  I might pop down to PB Tech today at lunchtime....

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  Reply # 373251 26-Aug-2010 17:49
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there are also heaps of 8 port switches that take 12DC supply, and i wonder if it is worth spraying some silicon inside to "marinise" it yourself... not sure how effective it would be with the salt air but might help it last a bit longer.




Qualified in business, certified in fibre, stuck in copper, have to keep going  ^_^

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Master Geek


  Reply # 373319 26-Aug-2010 19:41
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Hi Trevor

My 12V project was with a TV not a switch but the logic is the same. If the comms between your devices is ethernet then I'd just buy the cheapest one you can find that is definitely a 12V DC input... and then buy a second as a spare for when the first one inevitably corrodes! :-)

I suspect you will be putting it somewhere inside the boat off the flybridge or whatever so it should last OK.

Good luck!

Cheers

David



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  Reply # 373925 28-Aug-2010 13:48
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Thanks everyone for this - much appreciated.

Just one final issue I need to sort.  This is perhaps not the right forum but it's a follow on from the earlier question so I thought I'd try here first...

My GPS Display sends a "wake up" signal to other units on the network so everthing powers up when the GPS display is turned on.  However, my (much cheaper!) ethernet switch doesn't have the proprietary "remote wake" the other units have.

I think I'm correct that all I need is a relay?  Question is:  which one?  Boat is 24v DC and I'm going to have this from DSE  to feed my ethernet switch clean 9v power.  http://www.dse.co.nz/dse.shop/4c786941014f706e273fc0a87f3b06e0/Product/View/M9889

What I think I need is for the electrician to wire in a relay which takes the wake signal from the GPS display and in turn switches on the 24v DC power feed to the DSE adapter...and therefore to my ethernet switch.  Then, when the GPS is turned off, the relay would in turn cut the power...

To be honest, I'm close to being out of my depth...but would one of these do the trick? 
http://www.jaycar.co.nz/productView.asp?ID=SY4041&keywords=relay+24v+dc&form=KEYWORD

http://www.jaycar.co.nz/productView.asp?ID=SY4007&keywords=relay+24v+dc&form=KEYWORD

Electrican will be wiring it up but I can tell he's thinking this would all be easier if I just paid the $600 for the proprietary switch, so I want to at least present him with everything he needs to make my $60 version work!

Thanks again

 

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Master Geek


  Reply # 374887 31-Aug-2010 14:08
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Hi Trevor.

Without knowing much more about the 'wake up' signal I suspect you are on the right track.

Of course, the simpler answer if you have a spare circuit on your DC switchboard is to simply have the ethernet hub turned on/off by it's own switch OR have it linked to the same switch as the GPS so it just turns on at the same time. It means you have to turn it off when you stop motoring, but I turn off all instrumentation at the board anyway on my boat so that I know exactly what is using power!

For the sake of $540 it may be worth flicking a switch twice a day.

Cheers

David

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  Reply # 375039 31-Aug-2010 18:34
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I suspect that this may be related to what I saw in a hardened waterproof hub that I came across once with a whole lot of relays connected to the unused pairs on the cat-5 cable. I didnt really think much about it at the time, and since the hub was so much we ended up using a tupperware type box and some cable glands instead.

I believe it is still working to this day sitting in a hole in the ground in the middle of a friends property.




Richard rich.ms

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  Reply # 375901 2-Sep-2010 17:49
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If its wake-on-lan, then the hub shouldnt matter - the lan ports on all the devices stay active all the time listening for a wake packet on the lan port.

http://en.wikipedia.org/wiki/Wake-on-LAN

But that all depends on how the signaling works.




Ray Taylor
Taylor Broadband (rural hawkes bay)
www.ruralkiwi.com

There is no place like localhost
For my general guide to extending your wireless network Click Here




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