Running a DSL Router From a 12v Battery (Anti-Loadshedding DSL)





Introduction: Running a DSL Router From a 12v Battery (Anti-Loadshedding DSL)

Welcome to my first instructable.

Due to "loadshedding" in South Africa, which is nothing more than a fancy term provided for controlled rolling blackouts from the national electrical provider Eskom (loadshedding status page), we find ourselves for up to 4.5 hours being 'loadshedded' sometimes even more than once per day. This gets implemented by Eskom due to power constraints on the national electric grid in the country, after Eskom has neglected to build new power plants over the last decade for the increased demand for electricity and not performing regular maintenance on the older power plants.

So a lot of people are installing solar panels and generators at their homes, but what if you live in an apartment? 200 units in the apartment complex each running a generator? Better yet if you don't have a balcony/garden were do you put the generator?

I have a UPS protecting my computer equipment and noticed that even during these blackouts my DSL provider actually stays on, but my UPS can only manage keeping the DSL router up for 40 minutes.

I did some research and decided to go the route of using an AC/DC Charger from the mains to charge a 12v battery which I will then use during the blackouts to power my DSL router which can provide me with some entertainment plus allow me to continue working (IT Engineer). The goal is to run the router on DC power straight from the 12v battery avoiding the DC -> AC -> DC conversion that would take place using an inverter in between and the losses that come with each conversion. These losses contribute to shorter run times.

Below I'll be covering how to implement this simple setup using a standard ISP rebranded D-Link DSL-2750U router that has a 12v 1A power supply with a 3.5mm DC jack.

I won't be covering any other power supply specifications and I'm not a professional electrician. I do not take any responsibility for damages or injuries occurred following this instructable.

For this instructable you'll need the following:

  • 12v Battery - at least 7 Ah to 10Ah depending on desired run time (I'm using a 26Ah)
  • AC/DC Charger
  • Multimeter
  • Soldering Iron (I'm using a basic 45w model)
  • Solder
  • Wire cutter & Wire stripper
  • Utility knife
  • RipCord (I'm using 3Amp 48v rated RipCord)
  • DC Jack (I'm using a donor from another power supply due to 3.5mm being in short supply)
  • Cigarette lighter plug
  • Cigarette lighter socket with crocodile clips

This entire instructable was written and published from a laptop connected to my battery powered DSL router during loadshedding.

Step 1: Charge the Battery Using the AC/DC Charger

Since we are going to attempt to power our DSL router from a battery we should start by making sure that it's charged.

I'm using 10A AC to DC Multi-step charger that has: Over load protection, Output over voltage protection and Output short circuit protection.

For the battery I went with a 26Ah model, since you should never discharge these batteries beyond 50% of the capacity or else you are shorting the life of the battery, thus it gives me roughly13Ah to work with.

Depending on the size of your battery and charger this could take a couple of hours.

Step 2: Making Your New Power Cable for Your DSL Router

I'm using a cigarette lighter socket and plug for connectivity to make it easier to swap out or use other 12v devices already equipped with a cigarette plug directly from a battery. The crocodile clips also makes it easy to swap between the AC/DC charger and socket extension.

The cigarette lighter plug can be opened by unscrewing the the front tip and single screw on the body of the plug.

You should use a multimeter to measure your router's power supply to determine the polarity of the DC jack. My model has a negative barrel (exterior) with a positive center(interior) -(+)-

So on one end of a piece of RipCord, about a 1 metre should do, solder on your DC Jack and on the opposite end solder on the cathode(-) and anode(+) of the cigarette lighter plug.

Your cigarette lighter plug might come with a LED and resistor to serve as an indicator, it that case the long leg of the LED goes to the anode with the short to the resistor and from the resistor to the cathode.

Step 3: Connecting the Cigarette Socket

Remove the charger from the battery.

Connect the crocodile clips to the battery, e.g. red to positive and black to negative.

These days everything is color coded in one form or another if the crocodile clips are not color coded look at the wires, positive usually gets marked with a white line and the terminals on the battery have indicators on the casing.

If there are no clear markings use your multimeter instead to determine which is the correct ones

Step 4: Testing the New Cable & Connect It to the Router

Once you've plugged in the cigarette lighter plug into the socket use your multimeter to confirm that the polarity is correct.

The voltage reading should be about 12.8v on a fully charged battery.

The moment of truth.

Plug the DC jack into the router and turn it on, and in about 2 minutes (depending on the boot and authentication times) you should be online using a 12v battery.

Thanks for reading.



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    22 Discussions

    Can I use 12V 10 watts led driver for DSL Router

    led driver.jpgkit.jpg

    what if you used a device like this one? "50000mAh battery pack (K2).

    Multi-use All in One Charge
    One 20V/3A, one 12V/2.5A, two 5V/2.1A and two 5V/1A output allow you charge several devices like laptop, tablet, cell phone simultaneously.
    Ultra High Capacity 50000mAh
    Once Fully Charged, Our MAXOAK K2 Portable Battery Pack Can Charge Your iPhone 6 Plus about 11 Times, iPhone 6 About 17 Times, Galaxy S6 Almost 11 Times." ? would this be suitable to run a wifi router?

    I used two Ryobi cordless drill batteries in parallel to ensure longer lasting time.

    I used car battery .when i connected to router it burned.....I think there was a negative and positive side problem.What should I do to differentiate ?Now I just bought a new router.Please give me any idea.I shall be very thankful to all of you.

    1 reply

    It burned probably not because of wrong polarity, but because your router's working voltage was 9V, not 12. Always check the router's adapter beforehand to make sure you know the correct voltage required by the router.

    I've done the same and 'survived' 4 hours loadshedding with internet access off a 7Ah battery...small pleasures:-) I've seen other setups include a 2A inline blade fuse on the positive cable going to the battery to provide some protection to the 12v 1A DSL modem. Have you considered this option?

    1 reply

    It's the small pleasures that makes it a little more bearable.

    I also came across the inline fuse setups while researching this, and I actually have a fuse in my setup. The Cigarette plug that I use has a cartridge style fuse included - simply unscrew the tip and swap out the fuse.

    From the comments on the forums it seems like you should be fine without a fuse provided you don't charge the battery while using it to power the DSL modem. But I'm no expert ;-) and would rather be safe than sorry.


    Lekker man!! I have 6 x 12volt 7Ah batteries, what charger would you recommend if I want to run them in parallel ?

    Eskom eet my 2 keer per dag.

    1 reply

    Dankie Erik!!

    Avoid the old style automotive chargers sold at the Game stores. You need to look at 'smart' chargers as they are more efficeint and generally safer to use - almost a connect and forget charger. Higher Amp chargers will charge faster, but also costs more.

    My 10A 'smart' charger was about R1100 incl. VAT which should be sufficient for your setup sticking to utilizing only 50% of the batteries capcaity should allow you to recharge with a little over 2 hours or less depending on how much they get drained during use - router does not realy draw the full 1A.

    If they are identical with regards to the Ah rating, age and type there should be no issue charging in parallel. Otherwise charge them individually first before running/charging them in parallel.

    Mixing battries in a powerbank is like mixing RAM modules of diffirent speeds in a computer. With RAM you get capped to the module with the lowest speed, the same applies to batteries - the worst battery drags down the entire banks runtime.

    Also note 12v charger actually outputs closer to 15v so I'll advise on
    disconnecting everything from the batteries while charging.

    'n Boer maak 'n plan - A "farmer" makes a plan :D
    Its a pity current legislation makes it difficult to move to a more localized solution.

    nicely done. as a fellow south African I am experiencing the same issue as you in came up with a similar solution but I used my old laptop battery. works like a charm.

    1 reply

    Thanks! Sounds great, how long does it run for? Do you power it straight from the battery or is it wired like a laptop were it just keeps running from the battery after the mains drop?

    in india ,load shedding is a common phrase since decades in most of the states and we are quite used to this exercise round the year.sad to know you also suffer from this lapse of planning.

    1 reply

    Unfortunately with us the planning and warnings was there in the late 90s but nothing was done since.

    He he. When I saw the word loadshedding I knew you where from South Africa. Eish

    1 reply

    Yeah. We aren't the only ones, some other countries also have loadshedding and use that exact term, difference being they are actually addressing/addressed the issue.

    Dit lyk na wonderlike idee! Sal dit defnitief moet probeer. Dankie.

    1 reply

    Great solution!

    How long have you been using this setup? Any hiccups?

    Having blackouts like that would wipe me out, as I do all my work online. Good to see a solution like this. Thank you!

    1 reply


    I have mostly been stuck in traffic (traffic lights being out) or lucky enough to be somewhere else with a generator/internet access so I've only used it a couple of times thus far, but I've had zero problems with this setup.

    Wrote this during a 4.5 hour 'shed' only had to charge the battery for about an hour afterwards - which means I should be good for back to back loadshedding.