sourcing or making AA/AAA battery eliminator shells

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Several times in the past I've tried powering battery devices that have no power supply jack by making little wooden dowels with screws on the ends connected to wires to simulate the physical size of a AA or AAA battery.

But this always seems to end in frustration for me, as I get bad connections. Either the screw is hard to solder to and I have a poor connection there, or the screw doesn't make good contact with the terminal in the device due to its slotted rounded shape not matching the flat button on a battery. In my latest attempt with bic pen bodies and wires soldered to screws, I put aluminum foil between the screws and that seems to also make a poor connection that increases in resistance as oxidation occurs over time.

So I'm wondering how to get something more reliable:

1. Frankly I'd like to just find a commercial product shaped like a battery with some means of attaching wires to it, so I don't have to work on getting the physical shape just right. I read elsewhere about someone who used rechargeable batteries that also had solder terminals on the sides, but I don't know where to find such a thing. This is not ideal because over time the batteries inside could fail overheating or shorting, but perhaps serviceable for light use. What would be better would be battery sized shells that already had wires coming out of the sides. Anyone know a source for such?

2. If I can't find anything actually shaped like a battery, I'd like to improve the contact of my screwheads with copper foil or something similar. This product looks like it might work, but I am curious if there are better alternatives:

http://www.amazon.com/JVCC-CFL-5CA-Copper-Conductive-Adhesive/dp/B000UZ8SJK

I just realized from posting on this board that there is another option:

3. Take the device apart and solder my own power wires into the device. Unfortunately this approach doesn't work for many of the miniature sealed devices that I want to use this with, but anyone have advice for how to solder directly to the battery terminals (typically bare silver-colored springy wires)?
 
I use copper tape for shielding cables (I think that's what its intended for) working with it is easy, very pliable. You can solder on it, its used in stained glass (where it is soldered) Since I use it inside diy cables I can't say how it holds up to oxidation.
 
I use wooden dowelling, with nickel plated drawing pins (thumbtacks) for the negative terminals and cheese-head machine screws for the positive terminals.

Wrap the end of the wire around the pin of the thumbtack and solder it. Cut a notch across the end of the dowel to clear the wire, then press the thumbtack into the end of the dowel.

Wrap the end of the wire around the shank of the screw and solder it. Drill a hole into the end of the dowel to make a tight fit for the screw. Cut a notch across the end of the dowel to clear the wire, then press the screw into the end of the dowel.

I use cheese head screws (head is cylindrical shape) because I have them and they take solder easily, but I have yet to see a holder where a round head screw would not make reliable contact. Most modern battery holders have moulded plastic guards to prevent contact if a cell is inserted the wrong way around. Before such guards became common I just used thumbtacks on both ends.

If you can't find nickel plated cheese head screws, look for "hex head" screws, designed to be tightened with "Allen" or "Torx" bits. These are commonly used where appearance is important and usually have a chrome or nickel finish.
 
Funny, I happened to run across that Sennheiser recently when I bought a Sennheiser wireless lav set, and that was responsible for my thinking "If Sennheiser makes that surely someone else must make them cheaper and in other sizes". And in fact that's part of why I started this thread. Alas that Sennheiser seems to require a rather large slot for the cable and a battery compartment that holds both batteries facing the same direction, which is rare, but thanks.

What I'm currently looking for is a single AAA sized one for a sony digital recorder. The fit on the battery compartment fit is tight enough that I'm not sure I could even add a layer of tape and foil to a battery and still have it fit.
 
Don, thanks for those ideas. I think your woodworking skills and/or equipment must be better than mine; I don't think I could cut a slot accurately with my jigsaw, nor am I confident in ability to drill a hole in the exact center of a dowel end. I suppose I could put together some kind of jigs to do it, but that's not my cup of tea.

Most imporantly I've found that the length is the hardest part in making these things; too short and they don't make contact, too long and they don't fit. When you have a variably-sized gob of solder between the screwhead and dowel it all seems to require more accuracy than I can easily muster, although I suppose a few rounds of trial and error, sanding down between trials could get it right. I'd rather spend my time doing something else.
 
Have you seen "solder lugs"? It's like a lock washer with a long extension off one side; tinned for soldering to. You could sandwich one of those under the head of the (brass) round-head screw in the end of the dowel, and solder your voltage lead in the other hole in the lug. One in each dowel. Hope that works -- I'm going to try it, too!...geodejerry
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.