Archive for the DIY Category

Hot swapping battery for my mobile 3G router

Posted in DIY, gadgets, photos on 13 October, 2010 by Chips Maker (since 2010)

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I don’t want to stay in the office. I want to enjoy life. I want to go wherever I want. All I need for work is a notebook computer connected to the internet. I have an unlimited 3G data plan but apart from the notebook, I also have a smart phone for personal stuff like twitter, email, etc.

A mobile 3G router makes sense. One data plan for all devices. Thing is, the internal battery is only good for about 3.5 hrs.

And if I go to a beach and enjoy the sun, then go to a coffee shop and sip and read, then go to an art gallery for the latest exhibition, then go to a park and take photos of a dragonfly standing at the tip of grass, or kids laughing and playing with their dog, then go to a market and buy food and cook for dinner, all these while working …

I work 10 hrs a day. Yes as much as I enjoy life to its fullness, I get a lot of things done! At the same time! I have 3 internal batteries to swap with. Now the problem is, the router stops running when I change the battery. Not really a problem but I have an app running for work and it needs continuous data feed from the net. And what if I’m enjoying one of my favorite songs from an internet radio station and it’s time to change the battery?

I know there are battery products that gives you hours of power, but they’re much more expensive than they should be and over the year I’m having 3 internal batteries now. It really isn’t worth it to buy a huge battery and throw away the already-good-and-nothing-wrong internal batteries just so that the connection will stay.

Wouldn’t it be great if there’s a quick fix to keep the router on all the time. I mean ALL the time even when I change the battery! And yes there’s just one such solution, and it’s cheap.

The router takes in 5V from the transformer but the internal battery provides 3.7V

So I guess a power supply with more than 3.7V should be good enough to keep the router running (and the extra 1.7V is used to charge the battery?).  Anyway, here we go, 4 rechargeable AA @ 1.2V giving 4.8V in total.

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Notice that if i use the non-rechargeable AA batteries off the shelf, I’ll have 4 X 1.5V = 6V which is too much for the router and might just blow it!

And of course I need a box to hold the batteries together.

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And a bit of wiring then I’ll be literally having a Plug-n-Play !

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Now, when the router is up and running but the battery is getting low, all I have to do is to plug in the battery box. Now the external batteries are powering the router, I can then take out the internal battery and the router will still be running! Then I put in the second fully charged internal battery. And when it’s ready, I can then unplug the battery box and Voila! The router is still running as expected! I love the song and it didn’t get broken!

BTW, if all the internal batteries have gone low, the external battery box is good enough to keep the router up for another 3 hrs!  Together with the 3 much lighter internal batteries, I’m now having 3+3.5X3 = 13.5 hrs of uninterrupted stream of data for work and songs!

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