Battery holder

[Jack Crow]

Hi all,
Cold and miserable night here in Virginia Beach. This town is awful in snow.
Got Roxy Music on the stereo and just finished this project.
Wanted to share.

In the ham radio world we tend to collect a lot of stuff that over time morphs it's way into useful junk.

Standard example.
We buy our selves a new hand held radio and a bunch of overpriced accessories.
We love it, we use it, and over time things start to break down, and eventually the radio is not worth repairing.

What is left behind is a bunch of still good rechargeable batteries and a charger.
Why waste it.

Some years back I picked up a series of Wouxun handhelds radios.
And some extra batteries. These batteries are great and best of all, they are cheap!

For the moment my radios are still good.

Got to looking at the batteries and wondering if I could use them for other projects.
7.5 volts, two amps LiOn aka Lithium Ion packs. Same deal as we have in our phones.

Back Story.

Many years before my x boss wanted a battery pack to run a bit of communications gear.
He did not want to invent one.
So I showed him my ham radio at the time, an Icom U16.
It used a big slide on pack.
So the boss worked with his machinist and developed a battery slide for the packs and uses them as daily production.
It was a complex beast but it worked with high reliability in the application.

With these printers we can do better.

Grabbed a Wouxon battery and started in on the measurements.
What your looking at here is the radio, battery, and the new holder.
This is to give you an overview of how it all interconnects.
The battery becomes the back of the radio, and now it saddles into the new holder.
You can also see the complicity of the attach points.
All kinds of raised and depressed areas.
Worked out a cute way to check if it all lined up.
You know that thermal paper we get from grocery store slips.
I put a layer between the new holder and the battery.
Pressed firmly, and made an impression on the paper.
It was a good trick to measure the fitment.
1-7-2018 001.JPG

Had to make this as two parts due to the limits of the free 3D cad software I was using.
That is what the three hex cap screws are all about.
They stitch the two parts into one whole.
1-7-2018 003.JPG

The top section was tricky, having to work with the built in flat spring in the top of the battery house.
As the spring is brought back it engages metal tabs in the casting of the radio.
Had to make due with what I can fabricate.
The hard part was placement.
First try was too tight, second was two loose, third time I had it close, and the forth edition it was just right.
The two part build was not a bad idea after all.
I can print a new top a lot faster than a whole holder.
Swapping out duds until I get it just right.

I can shake the thing and the battery will not flop out of the new holder.
Bang it on the table and it stays put.

This brings up the question on how to get the voltage out of the battery.
I recovered these 'push pins' from a dead two way radio and adapted the design to fit them.
Found some proper parts on Amazon that I most likely will order.
For the moment they work well. Soldered on a little LED to prove that point.
1-7-2018 005.JPG

These next few are overview photos of the whole assembly.
You can see the oem molded slide points to pull back the flat spring, I make use of that feature.
1-7-2018 006.JPG
1-7-2018 007.JPG
1-7-2018 008.JPG.

At this point I have hit the 97% of the design goals.
Make a working battery adapter.
Whats left is window dressing.
Install mounting points so I can attach the unit to some future portable electronic project.

What comes to mind first is some radio direction finding gear I use.

Hard to imagine that a Doppler RDF unit is at it's heart a fancy audio analyzer.
And a very sensitive one.
In the past two vehicles, enough of noise from the alternator oozed through to upset the readings.
Alternators were fine, as were the vehicle battery. (think of it as a big capacitor).
Noise immunity is not the best feature of the unit.
Used to travel with a 4 amp gel cell on the floor of the truck just to run the RDF unit.
Snap two Wouxon packs like these to the back of the RDF and it will run for hours.

Follow up additions to this item.

Get the new push pins installed into later revision housings.
Might want to go the deluxe route and add some + and - signs for the polarity.
Perhaps some bumpers to cup the battery into place.
Build in an internal on/off switch to hard disconnect the packs, or perhaps some kind of fuse. Time will tell.

Have a bunch of ideas for these things.

First off, need to show this to the ham radio community.
I want to get their ideas on how surplus batteries can be adapted for other tasking.

So that is where the head is at.
Be well all.
Jack Crow aka Radio Mike in Virginia Beach