Making a D cell mintyboost

Ideas and questions about MintyBoost kits

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kevinrs
 
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Making a D cell mintyboost

Post by kevinrs »

Not really a support issue, just looking for ideas from the community.
Anyone found a good way to build a D-Cell mintyboost?
I've made a standard mintyboost, it works, I've decided to make a high capacity one with 3 D batteries. Ordered and built the kit, but haven't figured out what to hold it in.
I came up with the idea of using an old flashlight, before seeing the 2-3 examples of people doing the same, but looking at flashlights, most are going to be difficult to work out how to replace the reflector/bulb assembly with the circuit board, because the reflector and bulb both make the electrical connections and physically hold the batteries pressed down into the flashlight against the spring.

I do have 1 2-cell pushbutton flashlight that would work, since the batteries load at the bottom, and the switch mechanism holds back the batteries. I could solder wire to the contacts at the top end, replace the reflector and lens with a thin piece of wood or plastic cut into a circle with a hole cut for the USB connection, but I'd like to go 3 cell, and not have the unnecessary flared out end of the flashlight there.

I found I have 2 different cardboard tubes that fit D cells relatively closely, about like a flashlight body, not too tight to fit wires in as well. One is a hard thin walled(just over 1 mm) tube from a roll of aluminum foil, the other is a thicker walled longer tube of unknown origin. I'm really leaning towards using one of these, as it would allow 3-cell, and make it slim, but I haven't worked out a good way to close the ends, and do it in a way that will allow changing batteries, and a way to hold the batteries away from the mintyboost and against the spring.

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adafruit_support_bill
 
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Re: Making a D cell mintyboost

Post by adafruit_support_bill »

Take a walk through the plumbing section of your local home improvement store. Lots of PVC pipes and fittings there.

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kevinrs
 
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Re: Making a D cell mintyboost

Post by kevinrs »

I've thought of that, maybe I'll take a closer look, anyone know which pipe size fits D batteries?
Still would have the problem of what makes the battery contact at the mintyboost end and separates them from the mintyboost.

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adafruit_support_bill
 
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Re: Making a D cell mintyboost

Post by adafruit_support_bill »

anyone know which pipe size fits D batteries?
D cells are typically 1.3" OD. Schedule-40 PVC marked 1 1/4" is typically 1.38" ID.

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kevinrs
 
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Re: Making a D cell mintyboost

Post by kevinrs »

Really, when I started thinking about this project, at first I was thinking of doing the solar panel-USB / DC / Solar Lithium Ion/Polymer charger-Lithium Ion Battery Pack-mintyboost project, but when looking at the fact that the solar panel would take in power slower than my phone would use it, so I'd mostly have to charge the Li-Ion off external power, and I'd rarely be actually using it(a couple of months at least between uses, not good for those batteries), it's just making more sense to use disposable batteries.

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