Concealing portable power supplies in small spaces

severedblue · Post by **severedblue** » Wed Jan 12, 2011 8:01 pm

Gents

I'm working on various grav tank kits:
http://www.games-workshop.com/gws/catal ... GameStyle=

The inside is quite small and I need to squeeze a battery with enough voltage inside to at least light the engines and the cockpit.
http://au.element14.com/renata/vbh2032- ... dp/1216359

tetsujin · Post by **tetsujin** » Thu Jan 13, 2011 11:21 am

severedblue wrote: The inside is quite small and I need to squeeze a battery with enough voltage inside to at least light the engines and the cockpit.
http://au.element14.com/renata/vbh2032- ... dp/1216359

What is your question?

I've attempted enough battery concealment in relatively small kits (12cm-18cm Gundam kits mainly) to know that I find it difficult and frustrating. And for the amount of power you get, the coin cells are expensive. (A set of AA's will light a LED for about a week... A coin cell might last for a day if you're lucky.)

CR2032's, however, are probably the best value among coin cells. If you want to power with coin cells (and if you can squeeze in a 2032 somewhere) I think it's the way to go. But mostly I've shifted my efforts into trying to fit a power supply into the base... Though of course that's not necessarily going to work with a gaming mini.

One thing to keep in mind is that a battery holder adds a lot of bulk: in this case the holder for your 20mm wide, 3mm thick coin cell is 23mm wide and 6mm thick. You can save space in some cases by creating your own battery holder and possibly integrating it into the model. I've done a couple of these with sheet styrene and strips of brass.

To actually change the battery, you're going to need either a removable panel somewhere, or a place to access the battery that will be out of sight.

karim · Post by **karim** » Thu Jan 13, 2011 12:29 pm

A method I've used to great success in the past is putting the battery compartment in the base, then building a small power connector into the stand mount. Headphone jacks work really well for this approach, and they come in three sizes

severedblue · Post by **severedblue** » Thu Jan 13, 2011 7:33 pm

Here is a better image... notice the clear base...
http://img234.imageshack.us/img234/9408/falcon1mo.jpg

These are on a tabletop battlefield so power has to be self-contained.
I was thinking intelligently placed stereo jacks was the answer.

I guess I should get creative with my base modelling then and start making plans.

Or I should mount the battery in the troop compartment ... even though I did want lights in that compartment... also though it's too small to realistically house any number of troops or detail....

PS: Gundams are aweomse. I'm building the Exia 00 Ignition Mode and that's what has inspired me to do more LED work. Also have a MG Kamfer that I want to put lights in.

MillenniumFalsehood · Post by **MillenniumFalsehood** » Tue Jan 18, 2011 1:02 pm

You could try fitting a rechargeable battery in the model somewhere and then put two contacts on the surface, disguised as decorative parts (photoetch comes in handy here). Then build a small wand, for lack of a better term, with matching contacts on the surface and strap it to the model for a couple of hours till the battery charges.

Chacal · Post by **Chacal** » Tue Jan 18, 2011 3:40 pm

You could try to sneak the CR2032 into the base, or rather make it the base using two support pins for the model — one comes from the top [+] the other around the rim [-].

severedblue · Post by **severedblue** » Wed Jan 19, 2011 10:08 pm

Hmm the challenge is now to design a flying base that isn't bulky to house the batteries / electronics... working on that now...

EDIT:

After seeing this thread
http://www.starshipmodeler.net/talk/vie ... 0770145718

I have decided that the only item that should be in the model are LEDs, optics / shrinkwrap. I will install mini-plugs or connectors and house the power / logic in the base

robiwon wrote:Well a lot have been swooning over those mini plugs. At $12 for wired plugs sounds like a great deal. But of course there are other options if you can do it yourself, check these out. Compare prices.

http://www.radicalrc.com/shop/?shop=1&cat=56

That way I can change the power / logic of the model without having to worry about spacing requirements inside (space is very, very tight). It would be nice to have it all self-contained but, due to the space constraints a very small plug is the next best thing.

I'm going to be magnetising the parts so I can easily open and close the model to see the internal and minimal electronics, since I have to magnetise the weapons anyway to make them interchangable.

I'm also going to sneak EL Wire into the crystal cannon
EL Wire - http://www.elec2go.com.au/category49_1.htm
Crystal Prism Cannon - http://www.fast-autos.net/diecast-cars- ... 821673.jpg

severedblue · Post by **severedblue** » Sun Jan 23, 2011 5:24 pm

An update

I was looking at Arduino microcontrollers then saw Lithium Ion batteries and chargers
Lithium Ion Charger - http://www.protogear.com.au/product_inf ... _id=100165
3.7V LiON battery - http://www.protogear.com.au/product_inf ... _id=100166

I need to constrain the height to about 4cms flying base so I was going to combine the battery system with electronics and a base (shown below).
http://www.hlj.com/product/LFTFP-250

I'm going to connect the electronics in the base to the kit using a deans plug or similar. I'm wondering if I can use a mux so will be doing research. I know the MUX will reduce the number of data combinations I can use but I need to constrain the number of wires going into the model.
http://www.jameco.com/webapp/wcs/stores ... 1_13098_-1

Will keep this thread posted. I am waiting for my model kits at the moment before I plan further... they're being shipped in from England.

I'll post pics of the kits once they come in to give contributors an idea of scale.

This is a major project for me that will call in all of my crafting skills. Looking forward to making it happen.

tetsujin · Post by **tetsujin** » Mon Jan 24, 2011 4:55 am

severedblue wrote: I'm going to connect the electronics in the base to the kit using a deans plug or similar. I'm wondering if I can use a mux so will be doing research. I know the MUX will reduce the number of data combinations I can use but I need to constrain the number of wires going into the model.

I'm not sure I understand... You want to use a multiplexer? Why? Are the lights going to be animated or something?

If so, you might be better of just putting the micro in the model itself, if you can manage it. A while back I made these boards with the aim of creating the smallest microcontroller board I could for model projects:
Raven boards

About 10mm x 9mm in the smallest versions...

Here's the thing: if you put an IC inside the model, whether it's a dumb multiplexer or a fully programmable micro, its size is going to be mostly just a function of the number of pins it's got. So it pays to make it an IC that can do the whole job... Something to consider anyway.

severedblue · Post by **severedblue** » Mon Jan 24, 2011 6:42 am

Might I ask that we may find a means to profit from your hard work, creativity and ingenuity.

Originally I planned to have only LEDs in the model so that I could store the microcontroller on the outside (an Arduino mini)? in a scenic base.

But seeing as you have a 11mm x 10mm PIC controller board may I ask to be with your next batch of boards? Maybe I can make it worth your while... I would need 10 of them at least lol (9 tanks, 1 spare).

My question would be... where are your LED Drivers, your voltage regulators? Other than the micro and resistors are there any anchillary electronics?

I was thinking of making an Armored Core kit myself (still trying to finish S Mode in AC4) but need to finish my grav tanks first, my MG Ignition Mode and my MG Kaempher kit.

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Concealing portable power supplies in small spaces

Concealing portable power supplies in small spaces

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