Tuesday, 8 September 2015

Latest Project

As mentioned in an earlier post, the old Zoom wireless router is portable and has a battery which has a life of approximately four hours before requiring a recharge.  The recharger is 240V but it doesn’t have a label stating the DC output.  Rather than run the inverter to recharge the router I’d like to recharge it using the boat 12V system.


As you can see, the first problem was neither the Zoom or the 240V charger had a legible output voltage.


Not to worry, a little searching on the internet revealed the DC charging details are 5.2V and 2A.  That rang a bell in my head.  The same voltage as a USB port!  We actually bought two 12V USB chargers last year.  Jan uses one for her iPad and the other is a spare.  Digging further through the cupboards I found a cable that had a 12V cigarette plug on one end which happened to have the same size plug as the Zoom Router on the other.


A   The original 240V charger

B   The 12V plug with a plug on the other end that fits the Zoom

C   The 12V USB charger and cable

My idea was to cut the small (micro) plug off the USB cable and also cut the plug that fits the Zoom off the cigarette plug cable.  I would then connect these two cable together which would enable us to recharge the Zoom router using the 12V USB charger and modified cable.

One concern was the thickness of the wires in the USB cable.  They were probably going to be very thin which would likely create a voltage drop problem.  In an effort to counter this possibility I cut the USB plug off the cable as close to the end as possible.

After stripping back the black cable from the cigarette plug I found the expected red & black wires.  The USB cable had four wires.  I guessed (correctly) that the red wire was positive and the wire at the opposite side was the negative.  The middle two wires weren’t required

4 wires

I offset the joins on the red and black cables in an effort to ensure the positive and negative joins couldn’t accidentally touch.  Actually joining these two wires proved to be the most difficult past of the entire project.  It’s my eyesight.  Having only one old eye means I can no longer judge fine distances. Eventually I managed to twist them together.


Then I soldered the joins and taped the individual bare connections.


Theoretically the two bare portions can’t touch each other.  If you are wondering about the strip of plastic above the cables it is a short section of plastic cable tie.  Jan and I bought a large bag of cable ties for our bedroom bondage games.  It’s amazing what you can do with cable ties, wet celery and an egg whisk! Winking smile

I’m going to tape the section of plastic cable tie into the join to give it additional strength.

 1st tape

Taping the individual joins.  Using heat shrink sleeving would have been better.  But I don’t have any.


Final join.

The cable was then inserted into the USB plug which was in the 12V socket.  I checked the voltage with our cheap Maplin multimeter.



The other end of the cable was then plugged into the Zoom

power on

Red charging LED.  Looks like the project might have been successful!


Ade said...

Nice work Tom always great when it ends in success.

Sue said...

Clever clogs!

Tom and Jan said...

Always thinking Sue (well almost always!)