zondag 12 november 2017

3D printed Racal Cougar Battery

I have been thinking of 3D printing accu's for the Racal Cougar for a while and this weekend i fired up OpenSCAD and had a go at it.

Like most of the older surplus radio devices there is a shortage of batteries for the Racal Cougar also. You can find them but most of them are dead and need their cells to be replaced. Replacing the cells is a matter of carefully opening the casing using a hobby knife or saw, removing the old cells and replacing them with newer cells.

The problem with this is there is little room in the casing and you need to solder the cells together which is tricky. I did this a couple of times and in some cases i even overheated the cells damaging them.

3D printed accu

Inspired by the MA-4516B from Racal i wanted to have something which i could take apart easily and use regular cells in without have to solder them.

Center, top and bottom parts

I designed the accu so it has 3 sections: a top section containing the locking mechanism and the power connections, a center section containing the cells and a bottom part.

Center part of the accu housing the cells.
Using the dremel i created two pieces of pcb and soldered battery springs coming from a couple of cheap battery clips. These boards connect the batteries together so the accu is made up of 8 serial connected cells.

When the bottom and top parts are connected to the center part using M3 bolts these boards will be sandwiched between it and stay in position.

The center contact is made up of a M3 Hex bolt cut to length and both metal lips on each side are coming from a dead donor accu.

What is next ?

The design is a tight fit, a bit to tight causing some tension on the bottom part. I need to redesign the parts so all parts fit without applying some tension. Also the metal lips currently come from a donor accu and i would like to create the from metal strips also so we have a 100% DIY accu.

8 opmerkingen:

  1. hi dave ,
    will you publish the sketch for the crypto key filler,
    or are we just to be left in limbo with that,if it's just a look what i've got thing ,then just say, and if it is then why the blog

  2. Hi Mick,

    Thank you for your response. There certainly will be an upcoming post containing the sketch and schematic of the programmer but before i do this i need to perform some work on the sketch to make it presentable. At this moment the sketch is hold together by virtual pieces of tape.

    Keep in mind this is a hobby project and after working on it for 8 months i believe it is ok to do a side project like the 3D printed battery every now and then. It doesn't mean i stopped working on the programmer.

    If you send me your call and email address i will create hex version of the programmer sketch and send it to you together with the schematic, this would allow you to build your own programmer.

    You can send it to @veron.nl

    73, Dave

    1. My email address got messed up when posting my reply it should be:


      Where you replace [my-call-sign] with my actual call sign

  3. thanks for the prompt reply dave,
    i do indeed realise that you have put in great deal of time and effort in to this and i might add some considerable skill, which i for one do aplaude

  4. Hi Dear PA5DOF 3 x 18650 fit perfect inside the batterypack.
    Possible to get from you the Datafile in OpenSCAD for the Batterypack?
    REG DL5QY Matthias n my Mail is mo@oesterwinter.net

    1. Hi Matthias, never thought of using 18650's instead of AA's. I'm still working on the design trying to get a better way to connect the negative leads to the metal lips at the side. Currently this isn't as easy as it should :-).

      Sure you can have the OpenSCAD files, after i have cleaned them up i will mail them to you.

      73, Dave

  5. Hi Dave
    If you look at the battery case for the TCA )not TRI) PRC-152 it may give you some useful ideas for the battery case. They have what looks like a nylon insert that has been drilled for the 18650s and they are a perfect fit. It could be a solution to print the case and drill a block of nylon to fit in and hold the batteries as they have done.