# Adding an on/off switch to a battery pack



## cbmar (Sep 20, 2006)

The battery packs broke off of two of my props w/ LED eyes. I'd love to replace them with battery packs that have on/off switches, but I can't find them at Radio Shack. (They do stock packs like that, but they take 4 "AA" batteries, and my props only require 2 "AA"s. Could I just put 2 batteries in something designed for 4 and still have it work?) Help!

-Chris
www.hauntstyle.com


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## Otaku (Dec 3, 2004)

Nope, the 4AA packs are wired for 4 batteries. You could jumper the empty slots by attaching a wire to the terminals in the slots to replace the missing batteries, though. To cut in an on-off switch, get a small SPST toggle or slider switch (both are available at R/S) and cut it in on one of the two wires coming from the battery pack. Do not attach the switch to both wires or you'll short the batteries. Attach the red wire from the battery pack to one terminal of the switch, then attach a wire to the other terminal of the switch. The new wire will go to the positve connection of your prop. Please verify the polarity of the wires before re-connecting to the prop - you don't want to fry anything. If this isn't clear, let me know and I can whomp up a quick drawing and send it to you.


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## Dr Morbius (Sep 21, 2004)

Yes you can, just put a jumper wire across the contacts on the empty slots. Just make sure the wires leading out are connected to the batteries.


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## Dr Morbius (Sep 21, 2004)

LOL! Otaku posted at the same time I did..What he said.


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## cbmar (Sep 20, 2006)

Thanks. Here's a dumb question though...
When I attach the jumper wire to the negative side, can I solder it to the spring, or do I have to attach it to the metal plate?

-Chris
www.hauntstyle.com


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## Otaku (Dec 3, 2004)

You can solder directly to the spring.


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