BenWa Balls - Can Someone Please Tell Me.....?

[ReadyOne]

Speaking of which, does anyone know how to convert a DC device into something that could accept live wall current instead.....?

Later! -X-

Sure, if you are a bit mechanical and can understand enough electricity to jump-start a car.

1. Go down to Radio Shack and get a Universal DC adapter. It is a replacement for the transformer/cord things that come on phones, CD players, boom boxes, etc. It will have several different plugs that go onto the end of the cord that mate with different size sockets on the devices.

2. Get a 2 blocks of wood or plastic about the same size as the battery. Length is important here, as you are going to replace two batteries with the two blocks. If they are too long or short then that won't fit tight and you won't get an electrical connection.

3. Put a nail or thumb-tack in the end to attach a wire from the adapter to. Cut the end off the cord where the adapter plugs attach. The cord splits into two plastic wires; one will have a stripe on it. Remove the plastic from the end of each wire to expose the metal inside. Attach the bared end of the wire to the nail or thumb-tack and hammer it into the block. You now have a couple of "dummy" batteries.

(With a volt meter or some careful checking of the adapter plugs and instructions, you may be able to identify if the striped wire is "+" or "-". Knowing this can get things right the first time in step 4 or cut down the number of combinations you need to try in step 5.)

4. Look at the pattern the batteries are arranged in. Metal straps/prongs connect the end of one battery to the end of another, + to -, creating a string of them. There will be one battery with a "+" end that connects to the device. The prong on the battery end doesn't connect to any other battery, and frequently a red wire comes off the prong and goes off to the controls. Likewise, the other end of the string is "-", black wire.

Replace the two end batteries in the string with your blocks. The thumb-tack end should not be placed against the prong that will connect it to another battery. You want to place it against the prong that conducts the electricity into the device.

(The other batteries remain in the device just to hold the blocks in place. They can be stone dead.) If you know which block is "+" and which is "-" then you can match the "+" and "-" with the two batteries that you replace with the blocks.

5. Set the adapter to 3 volts (or 6), plug it in, and turn on the device. If it works, fine.

If it doesn't work, turn it off quickly and reverse the blocks. (What you did was effectively put the batteries in backwards.)

If the controls are not electronic, then it might work fine with the wires reversed, save that the motors run backwards. For this application, I doubt that matters! For electronic controls, the + and - must line up.

If it still doesn't work, you may not have figured out the battery layout. Use some trial and error until you figure out which two batteries to replace (and which way the ends point).

6. Get some tape, glue, etc and make things mechanically secure.

IF you are a real do-it-yourselfer, have a voltmeter, want to solder, etc. you can do a real nice job and add a socket to the battery pack (also available at Radio Shack). But if you're up to that, you probably don't need these instructions anyway...

WARNING: You may be tempted to use a battery instead of a block of wood. DO NOT LEAVE A COMPLETE SET OF BATTERIES in the device. What can happen is that, if there is a complete chain of batteries between the two wires from the adapter, then the adaper will start recharging the batteries. This is not good.

Non rechargable batteries (like those alkalines everyone buys) will swell and expand and leak all over the device. They were designed to do this to keep people from recharging them (thus depriving the manufacture of future battery sales).

If the bateries are rechargeable, they need some electronics to limit the rate of charge, etc. The Universal DC Adapter doesn't have any. Using it to recharge batteries can charge them too fast and make them explode.

Read the fine print warning on the batteries about recharging; I've tried to explain the "why" of them above.

 

[Guest]

ReadyOne -

Thanks SO much for taking the time to supply such detailed instructions! With instructions like that, I should be able to pull it off - and perhaps rewire my entire house in the bargain!

Thanks again, be well!

-X-