Need To Build A Battery Replacement For Elenco 300 in 1 Kit

Thread Starter

HowdeeDoodee

Joined Dec 28, 2006
6
I got an Elenco 300 in 1 kit for Christmas. The kit eats batteries. The problem is the kit has no on-off switch going to the battery pack underneath the breadboard and connectors. I need ideas for building a "disconnectable" battery pack for the kit that sits outside the plastic breadboard and connectors. Six AA, 1.5 volt batteries power the unit. The voltages available in the kit are 1.5 volt, 3.0 volts, 4.5 volts, 6.0 volts, 7.5 volts and 9.0 volts.

Thank you in advance for your help.
 

shortbus

Joined Sep 30, 2009
7,330
If you leave a circuit built on the board it will continue to operate, draining the batteries. Or at least this is how the old ones were. To keep it from eating batteries, you need to remove all of the components/circuits when your done working with it, or remove the batteries.

Or you could add a "master switch". But this would mean modifying the board. Cut the link between the negative pole of the battery box and wire in a SPST switch. This would allow you to shut of the power to the board. The old manuals did have a warning to remove batteries when not in use, don't know about the new one.
 

Thread Starter

HowdeeDoodee

Joined Dec 28, 2006
6
Thank you for the suggestions. Right now I think I am going to add an external battery box and port the positive and negative terminals into the box on the underside of the board.
 

tracecom

Joined Apr 16, 2010
3,944
Thank you for the suggestions. Right now I think I am going to add an external battery box and port the positive and negative terminals into the box on the underside of the board.
I am guessing that the varying voltages in the kit depend upon being able to tap into the battery pack one cell at a time. If that is the case, then your external battery pack will need that capability as well. As such, there will be seven wires needed from the battery pack to the kit, which will be difficult to do from a standard 6-cell battery pack. You may find that six individual battery holders will be needed.
 

t06afre

Joined May 11, 2009
5,934
I am guessing that the varying voltages in the kit depend upon being able to tap into the battery pack one cell at a time. If that is the case, then your external battery pack will need that capability as well. As such, there will be seven wires needed from the battery pack to the kit, which will be difficult to do from a standard 6-cell battery pack. You may find that six individual battery holders will be needed.
That is one of the reasons why I asked for picture of the battery box
 

inwo

Joined Nov 7, 2013
2,419
Or this.....................
With a switch or matching plug.
Common battery pack.

Choosing and matching Vf should get closer.

Not as silly as it looks.:D
And educational!
 

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shortbus

Joined Sep 30, 2009
7,330
I am guessing that the varying voltages in the kit depend upon being able to tap into the battery pack one cell at a time. If that is the case, then your external battery pack will need that capability as well. As such, there will be seven wires needed from the battery pack to the kit, which will be difficult to do from a standard 6-cell battery pack. You may find that six individual battery holders will be needed.
That's the way mine is. That's why I said to switch the negative lead, it will cut out all of the voltages that way.
 

burger2227

Joined Feb 3, 2014
194
Or this.....................
With a switch or matching plug.
Common battery pack.

Choosing and matching Vf should get closer.

Not as silly as it looks.:D
And educational!
Instead of tapping between diodes which would require at least 10 ma of current to reduce voltage .6 volts, just tap different colored wires between the 6 batteries. 9 volt batteries don't deliver much bang for the buck. Less than AAA even.
 

inwo

Joined Nov 7, 2013
2,419
Instead of tapping between diodes which would require at least 10 ma of current to reduce voltage .6 volts, just tap different colored wires between the 6 batteries. 9 volt batteries don't deliver much bang for the buck. Less than AAA even.
I was thinking that, but then battery levels would get out of whack.

A few mA load resistor is simple enough.

Also, those battery packs are neatly packaged.
 
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