I need to know what fuse I need so I may "filter" enough current to power a set of small, travel speakers that use 4 AAA batteries. I want to hardwire these small spakers to the car because I'm tired of using up batteries weekly...
The Story:
I have a sony xplod system along with a hooker header-equipped 3-in flowmaster exhaust and t-tops. Of course, like mostly all of us, I like to speed and play music loud and have the tops down. I have a radar detector with an audio output which I have successfully found these $40 speakers to use with. They work great because even with all the loud noise, I'm still able to hear the beep of the radar detector when smokies are on the prowl. I've successfully hardwired the radar detector and I am looking to do the same with the speakers so I may hook them both up to a rocker switch and just flip the switch when I want to turn on the radar detector "system/setup". The speakers have the A/V output on the back (which I actually found a plug for). I just don't want to fry the tiny speakers without a fuse...Radio shack is clueless and so are the autopart stores...can anyone let me know what fuse to use?

 

you can't step down voltage with a fuse. What you will need is one of those power supplies for the car which has a voltage selector.
as an alternate solution, you can go to radio shack and wire up a board with some voltage regulators to get the supply down to 6 v.

As for the fuse, use a multimeter to find the draw of the speakers (unless it lists a draw), and use an appropriate fuse.

 

Ok. Where could I find the power supplies with the voltage selector? or the board with voltage regulators. The reason I mentioned a fuse is because of the way the hardwired radar detector works as well as any cigarette ligher "plug and play" device, like cell phone chargers, thats mainly what I'm trying to do...since all those products use glass fuses, I just need to know "which one" to use...

 

Walmart should have the selectable power supply.. Even radioshack might have it.
The board wouldn't be pre-assembled, you would have to make it using a small breadboard, and a voltage regulator with at least a 12 volt input and a 6v output.

Some cell phone chargers also step down the voltage to 3 or 6 volts. Look at a few, you may be able to find one that works.

To find a suitable fuse, you want to know how many amps(or watts) the device is pulling. Remember that watts = amps * voltage, so if you have one you have the other. To find this, hook up a multimeter inline between the batteries and the speakers. Most have the ability to measure draw. Turn the speakers on , and operate them at full volume, playing some music or something. When you find out how many amps are drawn, get an inline fuse holder and use a fuse that is about an amp more then the maximum reading you recorded. That way it wont blow under normal circumstances but will blow quickly incase of a short.
Let me know if you need and clarification.

 

This is the actual system that I have
http://www.creative.com/products/pro...ct=14061&nav=1
Is there enough info here, or will I still have to use the multimeter?

 

i did some searching and I think it pulls 3 amps @6 volts.

 

I actually decided that it would not be a good idea to hardwire the speakers since when you remove the power (remove batts) and then replace it, it resets the system. The volume is digital, and I would needed to have at "full blast". It resets to low with power restored. So even if I were able to hardwire it, everytime I hit the power switch, I still would have to adjust the volume...which defeats the purpose of "1 switch". But thank you very much for all the advice, I may need you for more help in the future.