DSL modem on 12V

[upny]

Hi

I´m about to put my DSL modem in the utility room. It would be about 1 meter (3feet) from the battery bank. The modems 230V wall adapter secondary is marked 12V DC. Could I connect it straight from the battery bank (of course trough a fuse) or do I need something to stabilize the 12V even more than the battery bank already do? The DSL modem is a ZYXEL Presige 660H series.

It would sure be nice to have a solar powered network at home.

Thank you guys.

Upny

[Psycogeek]

most certannly

it of course wouldnt hurt if you checked the actual voltage comming off of the adapter, and get the polarity correct, and of course the external fuse.

what an Easy item to transfer to your dc.

even if its a AC transformer, it is VERY likely to work, because it would have a dc converter internally.

if the transformer was highly regulated Exacting 12v, and your batteries are pumped up to 14.5 (well charged) then just the wire (like some small guage) would be sufficient resistance to drop the voltage a bit.

[ghurd]

Check the adapter under load and not under load.

Some of those adapters will go really high voltage with no load.

I have seen 12v wall warts go past 20v open circuit.

I would not think there would be any problem either way.

[jimjjnn]

I have a wallwart that goes to 21 no load and 13 at full load on modem. I took it apart and it is just a transformer, Bridge rectifiers and 2 filter capacitors. No regulation other than the load. My meter is 39 years old so accuracy may be off a bit too

[JeroenH]

I run my cable modem, router and switch from a 12V battery. No problem whatsoever, even though the router says it needs 12V AC I opened it up and saw a diode bridge so I figured 12V DC would do just as fine, and it did. Even my notebook computer which needs 16V DC runs off 12V.

I've had no problems, but you'll get no guarantees from me, either. Good luck!

[Trivo]

Here is a handy very simple fixed power supply i have used just change the voltage regulator 7809 (9V) for a 7812 (12v) or anyother voltage regulator you want

http://www.mitedu.freeserve.co.uk/Circuits/Power/9v2a.htm

Trivo

[jimjjnn]

The 78xx series of voltage regulators are great. I am having a little problem finding them now but there are lots of newer substitutes on the market that work much better. I have a few projects that were overloadind them but easy way around was a power transistor  on the 78xx output to give more output like the 2N3055.Had to heatsink a few but that is a good idea anyway.

[jimjjnn]

I have a notebook that I run from a Nicad battery that was given to me by my daughter when she worked for a Med equip co. They were throwing new 12volt nicads in the packaging away. She "retrieved" one for me 10 years ago and it still works. It's about 7"X5"X6' and runs my notebook for 2 weeks with it being on 24/7. Came with a pretty good sized wallwart to recharge it. I mounted a car cig lighter socket to the neat little carry case that came with it and use a plug for same connected to a heavy duty audio cable that fits the computer perfect I was tired of buying new batteries for PC as they would last only 6 months. At $178 each.

I also use the battery for a small car air compressor for grand daughters bicycle tires  

[johnagony]

Hang it on the 12V batts. Suggest a 500mA fuse in the pos, just in case..

PS. It was Noel Coward who said:

Television is something that one appears on, not something that one watches.

[jimjjnn]

Just took modem apart. It has a regulator screwed to the frame. Can't read the part number on it . Branded big "M" (Motorola). May be a 317 reg as I can just make out what looks like a ..17 .

[jimjjnn]

Dand !! Forgot to give voltage in and out of regulator. 13.4 into reg and 12.1 out into a large transistor which has it's own heatsink.