12V supply needed for wireless router

mike95490 · October 2010

At first, it seems simple, just an 18V PV, charge controller, battery, and automotive lighter cord to the router. But the router wants 12V, not 12-15V as the PV recharges the battery. Neighborhood of 1 A draw

So, I'm thinking of a DC-DC converter @ 88% eff vs. a Low DropOut linear regulator @ 70% eff.

Also thinking of using the morning star charge controller with the lighting timer on it, to shut the router off midnight-5am when nobody uses it, but would want it ON with daylight hours too. Other ideas ??

Also need to come up with a ~70w sine DC-AC inverter, to power a sprinkler system. I've got a DC system (8 station timer and valves) but the DC latching valves, dont. I've had my water tanks drained a couple times by sticking valves. (yes, i have all the right filters and pressure regulators, the imported DC latching valves are junk.)

dwh · October 2010

Re: 12V supply needed for wireless router

First question that comes to mind is does the router's wall wart put out 12vdc or 12vac?

Might be a dumb question, but I've seen both.

Cariboocoot · October 2010

Re: 12V supply needed for wireless router

This struck a chord and my two remaining brain cells fired up. Something about a charge controller with Voltage-limited LOAD terminals. I found this:

http://forum.solar-electric.com/showthread.php?t=9312&highlight=LVD+controller

Now I'm wondering if any of the Morningstar units also limit the V @ LOAD, as this would be quite a useful function. Naturally I can't find anything regarding that. Maybe you can search more fervently.

I don't think there are any PSW inverters below 150 Watt. Vis:

http://store.solar-electric.com/sa150wa12vos.html

That's all my brain can do for now. It's nap time.

Slappy · October 2010

Re: 12V supply needed for wireless router

Series Voltage Regulators

> IC 7812 keeps the voltage at a steady 12 volt.

niel · October 2010

Re: 12V supply needed for wireless router

Slappy wrote: »

Series Voltage Regulators
> IC 7812 keeps the voltage at a steady 12 volt.

there is a problem in using them with a 12v battery for when the battery has 12-12.8v on it which is typical there needs to be a few extra input volts above the regulator's output voltage for it to function. the battery voltage is too low for that ic to function.

n3qik · October 2010

Re: 12V supply needed for wireless router

I am using 3 LM317 for voltage regulation for my router (12 volts), smoke detectors (9 volts) and modem (9 volts). What happens is when the batt is at 12 volts, output is about 11.1 volts. The output will be about .7-.9 volts less then batt volts. I have had the battery down to 11.8 volts and nothing turned off.

AntronX · October 2010

Re: 12V supply needed for wireless router

I would try Cincon EC5BE02 15W DC-DC converter $35 from Mouser. They also have versions up to 72V DC input.

niel · October 2010

Re: 12V supply needed for wireless router

going by what ken is saying then maybe you should give the ic regulators a try as they are cheap.

vcallaway · October 2010

Re: 12V supply needed for wireless router

I find it strange that a router that has a car cord wants perfect 12v.

The ones I've looked at have an internal regulator or have a regulator in the car plug.

I have a couple of D-Link WAP's that I modified to power with 48v POE connections. Just jumped from the ethernet port to the power port. They had internal regulators. Worked great.

I would pop the cover off and see if it already has a regulator before doing anything else.

mike95490 · October 2010

Re: 12V supply needed for wireless router

router is a linksys/cisco WRT54GL (with modded firmware) and the wall wart is 12V dc I'll look for a internal regulator, but I doubt it has one, hence my desire for a stable 12V. It may be that the DC-DC is the way to go on this.
This will be going to a remote site on my property to be a relay link for a weather station. When rains start in, I have no access, so it needs to be standalone for 6 months.

vcallaway · October 2010

Re: 12V supply needed for wireless router

Dissecting the WRT54G version 8

If yours has the same power chip you will be fine.

bryanl · October 2010

Re: 12V supply needed for wireless router

A lot of electronic devices from NAS to routers to LCD TV's to external drives to low power computers are using 12v wall warts for their supply. Those power supplies are cheap and ubiquitous. They are inexpensive and provide a reasonably regulated voltage as well as current limiting and some other protections and features.

The difficulty for those who want to use these things in portable environments is that the power input is not specified other than by the output of its supply. (thanks for the tear down link, reverse engineering is one way to find out what the device really needs)

You can get laptop power supplies designed for DC to DC use that use 'tips' that not only provide the right power connector but also use resistors to program the power supply for voltage and current limit. These are programmable buck boost power supplies and easily found for up to 100 watts or so.

There are a couple of these things for amateur radio use, too, as some of the modern transceivers need 13.8v for best operation which doesn't happen with the ignition turned off. They'll handle 20 to 40 amps and some have adjustable output voltages.

The IC's supporting buck boost voltage regulations are getting rather decent. The automotive electronics market seems to be a major driving factor. The app notes for these devices could be used to make your own if you were in to that sort of thing.

Then there's the RV crowd. It is amazing how many of these guys see the '12v DC' on the power supply and figure that means 'RV battery'. I cringe at the thought of connecting a $300 TV that way but, it seems, others have no qualms. The fact that they usually get away with it tells me I'm a bit conservative in my estimation of the capabilities of the equipment. Trial and error is a good teacher but sometimes a rather expensive education.

BB. · October 2010

Re: 12V supply needed for wireless router

All the above is why I frequently recommend to purchase a nice little TSW AC inverter... For a 10-15% loss of efficiency, the gains in distance the 120 VAC power can be sent, the fact the inverters are designed to operate ~10.5-15.5 volts (or 24/48 volt bank equivalent), usually provide galvanic isolation (great for outdoors/wet locations), and that one "adapter" will power 99% of the various small stuff we seem to carry with us these days (battery chargers, camera chargers, tool chargers, cell phone chargers, Ipod/MP3 chargers, radios, TV's, computers, etc.).

Standardizing on one TSW inverter instead of suitcase of DC adapters (and possibly AC chargers too) seems to make a lot of sense.

One thing nice that seems to be happening is that many of the small devices are standardizing to operate from USB and USB chargers (I believe that is pretty much the new cell phone standard going forward now).

-Bill

vcallaway · October 2010

Re: 12V supply needed for wireless router

Electronic mfg are being pushed to create products that consume less and less power. A lot of modern tech uses 3.8v on board. They regulate down from whatever is stuffed in. Can be anything from 5 to 12v. Whatever the local Chinese mfg produces on the cheap.

Even the phones in my office work with either a 5v wall wart or 48v POE. All of our small hubs and wireless access points are running off of our 48v POE central switch. Makes managing backup power SOOO much easier. Most were either jumped internally or a breakout was made for the ethernet cable. We had a couple of small ethernet hubs that had regulators that could not handle the 48v so we just added a 12v regulator to our breakout box. The voltage drop was already bringing it down some but we wanted to be safe.

Only way to know for sure is to look.

notsobright · October 2010

Re: 12V supply needed for wireless router

hey, another WRT54G fan here.

If you check the routers wallwart output you will find it is actually much higher than the indicated 12vdc, the ones I have are all in the 15 to 16 vdc range.

I can confirm that the WRT54G series routers voltage is internally regulated.

for portable/mobile use I have been running them directly off the 12vdc battery with only a 2a fuse in line and have not had any problems even when charging.

westyd1982 · October 2010

Re: 12V supply needed for wireless router

I think most of the Linksys networking equipment has a built-in power supply that can handle 12v battery power (10.5-15v). I have an older 8-port wired Linksys router and a new Linksys WRT160NL that both work fine connected straight to my batteries. I've read on other forums that the WRT54G also works fine from battery power.

kc8adu · October 2010

Re: 12V supply needed for wireless router

set up a clearwire unit and one of the wrt54g series routers at hamvention.ran all weekend on a wheelchair battery on top of the truck.battery was at about 10v when i took it down sunday.the wrt units buck down from input to +3.3 and a linear reg for +2.5 and +1.8.
set the same up at the clubs field day op too.
great routers if you replace the caps.i use a 330@16 for the input and a 560@4 on the +3.3 output.both are solid polymers.hook it right up to your battery bank.

12V supply needed for wireless router

Comments

Categories