Replace AAA batteries with a rechargeable battery

[Geoffrey]

I can't find any .7 volt Zener diodes.

Maybe if I go to a 12.6 volt battery, I can find one that will reduce down to 4.5 volts.

You need 1N4001 diodes rated at 1amp, they have a forward biased voltage drop of .7 volts, just use as many you like in series to get the required output for a 6volt battery,

It's a bit like adding extra LED's to your lights, thus increasing there voltage requirement.

Anyway I'd personally try that myself first, if you use a voltage regulator it will dump the excess as heat, not what you want to do if using batteries.

Another way is a pulsewidth modulating power supply to control the mark/space ratio, that would allow the brightness to be controlled.

[fixit]

Thanks gentlemen and scholars.

I worked for 25 years repairing laboratory instruments.

I really enjoyed the work.

But electricity is one of those areas where it is obvious that only God knows the answers.

Matthew 6:14-15

For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins.

[Ted Dog]

you could also use a USB battery system that comes with all the circuits and abattery. One I got puts out 12v 9v and 5v USB at 2A made to charge samsung or iPhone.
Lasts a long time. Uses any voltage from 10 to 16 v dc to charge.

called a portable phone charger.

[linuxbear]

Thanks gentlemen and scholars.



But electricity is one of those areas where it is obvious that only God knows the answers.

When I was on one of the R&D teams I have been involved in, a mechanical engineer with a doctorate wanted to know how it was that I understood "all that arcane and invisible Sparky stuff"
told him that after you get shocked a few times, you tend to understand electronics a bit better...........

[fixit]

I learned a lot about analog TV sets.

It had not been plugged in or used for 8 years.

Using insulated wire cutters I cut a wire going to the picture tube.

Learned that capacitors have a very,very, long storage capacity.

[starhawk]

Newer TV's, I am told, don't have that problem. (I don't care to find out first-hand!) The fellow who said that, said that after two or three weeks, a modern set (tube or not) is quite safe to handle!

Why?

Quality. Stuff that was made even ten years ago was made less cheaply than it is now. Companies are always cutting corners everywhere that they possibly can. They use components that cost less. Those components, in turn, are made more cheaply. Their constituent elements are, as well. Everything is made more cheaply (and, therefore, at least to some extent -- more poorly), straight down to how the raw materials are hauled out of the dirt.

Kind of a shame, if you ask me.

[fixit]

Is the second project more efficient ?

http://johnarthur.wordpress.com/2008/06 ... regulator/

[fixit]

I put together a solar battery charger.

It can charge AA, AAA, and Li-F-PO4 batteries. ( 2 at a time.)

I was surprise to see it still charging even on cloudy days.



Andy

[fixit]

I got my step down board in today.

Test results look good.

http://i1289.photobucket.com/albums/b51 ... cc6aa2.jpg

[greengeek]

Looks good. Does the regulator get very warm? Is there any way to measure the volts/amps "in" versus volts/amps "out" when the torches are connected so that it is possible to calculate a comparison of how many watts are lost in the conversion?

If it seems efficient I would be keen to use that sort of module for a few projects.

[fixit]

It did not feel warm.

I was told that lost efficiency results in heat produced.

They claim 92 % efficiency.

After I get my project box in, I will hook up to my 3 flashlights that use 9 LED's on my bicycle.

I will post the results.

I am not too happy with the failure rate of some of the flashlights LEDs.

One lost 4 leds and the second lost 3.

But I paid only $5.00 each.

Guess I got what I paid for.

Hope you have a great weekend,

Andy

[greengeek]

I am not too happy with the failure rate of some of the flashlights LEDs. One lost 4 leds and the second lost 3.

Are the leds definitely dead? I have had torches where some leds would not 'ignite' when the battery voltage fell too low. eg: when the batteries were weak some leds would switch on and some would not. Looks like you are feeding 4.3volts out of your regulator - maybe that is too low and should be lifted to 4.5 or 4.6 volts? (not that I want to encourage you to overdrive the leds... as one of the other posters mentioned it is important to limit the current to each led.)

[fixit]

I raised the voltage up to 4.8 V, but no more of the "unlit" LED's lit up.

I have two wires each going into the + and - outputs.

I will solder them and see what happens.

Andy

I used to hate aluminum wires.

Their good qualities are that they don't break as easily as copper wires.