Electricity Help

[Toaster]

Hi Guys I am having a few problems.

1. When I test any my batteries, I test, it is the voltage advertised then it starts to decrease towards zero. This became apparent when my 9v that was powering my laser was making the laser bright for a few seconds, then dimming down really dark.

2. When reading off my test load, my mV reading starts pretty high, then without touching anything, The mV goes down, it drops hundreds of mVs. Its really confusing why this happens and of course its impossible to set. This happened both when using the 9v and when using four AAAs in series (6v 6A)

I am thinking the second problem might have to do with my driver (its a $2.50 constant Current cheapie) but it also seems to be linked to the first problem.

Thanks a bunch.

 

[DTR]

If you have tested two different power sources and used a LD and a test load that only leaves the driver that can be at fault.

 

[lasersbee]

Hi Guys I am having a few problems.

1. When I test any my batteries, I test, it is the voltage advertised then it starts to decrease towards zero. This became apparent when my 9v that was powering my laser was making the laser bright for a few seconds, then dimming down really dark.

2. When reading off my test load, my mV reading starts pretty high, then without touching anything, The mV goes down, it drops hundreds of mVs. Its really confusing why this happens and of course its impossible to set. This happened both when using the 9v and when using four AAAs in series (6v 6A)

I am thinking the second problem might have to do with my driver (its a $2.50 constant Current cheapie) but it also seems to be linked to the first problem.

Thanks a bunch.

You need to use a Power Source that has enough capacity
to power your Laser..

It is like using a glass of water (9 Volt battery@ ~200ma) running
through a garden hose or a 45 gallon Drum of water (2 X 3.7 Volt
batteries @ ~3000mA) running through a garden hose...

The more capacity... the longer the run time..


BTW... you have not stated the exact battery types/model that
you are using... I'm assuming standard non-rechargables... and you
have not stated the exact type/model of driver...

Where did you get the 6Amp rating on 4 AAAs in series...:thinking:


Jerry

 

[Toaster]

I also thought the 6 amp was bizarre, its from 4 AAAs "Kirkland(Costco) brand Alkalines" Rated for 1.5 volts. I dont know where the extra amps are coming from TBH.

The 9V was a Duracell 9V. Does the voltage declining mean that the batteries are "Dead"? Also I was testing on the terminals of the batteries.

The mV on the test load dropping, is associated with the the batteries or the driver? I am trying to figure out how to make a tiny red before my big blue.

Oh, also when using a driver, once it is set using a batter of say, 4 volts. If I change battery type, do I need to change the Pot as well? I think so but I am not sure.

And when I get my AW 18650, how do I hook it up to the driver of the test load?

Thats it
Thanks

 

[lasersbee]

The only thing you told me me so far is that you are using
crap batteries...

Did you not understand the Water/Battery capacity comparison
I explained...

Is this not a continuation of your similar Thread here...

http://laserpointerforums.com/f52/tale-ghetto-driver-55924.html

It seems that you need to do a little more reading on the Forum
and on Google in general to bring you up to speed about basic
electronic theory...

It seems to me... what you are doing similar to saying
"Hey guys I just bought a Boeing 747... can you tell me
how to fly it".... rather than taking the tome to learn to
fly...

I just read that entire Thread...
Most of the questions that you asked on that Thread...you
could have easily answered yourself with just a small amount
of effort doing some basic research on your part..


Jerry

 

[Toaster]

Its actually different because I got the driver to work but the power supply seems to fluctuate strangely

 

[Toke]

I recommend that you stick to one tread and include pictures and full descriptions of your problems. That way you will avoid advice based on guesswork.
And try to avoid that yfrog thing, I can't be the only one whose's machine refuse to show it.

 

[Toaster]

Oh sorry, its part of image shack so I thought It would be cool

 

[BShanahan14rulz]

9V battery = bleh.

AAA probably shouldn't be pumping 6A.

Basically, driver says "I need this many volts, and this many amps"
battery says "ok, I have the volts, but I can only give you this many amps..."
so driver makes do with what it has available.

 

[Toke]

An AAA alcaline has an internal resistance of app. ½ Ohm.
That means you can get 3A at zero volts, that is when you short it through a meter.
Or e.g. 1A at 1V.
That gives 1W and is the main reason you should believe in any Chinese 1xAAA flashlights saying 3W.

 

[Toaster]

Thanks guys. Helpful. I am a trying to make less posts. If anyone can help me, here, without getting upset, one of the only questions I dont know is how to connect the 18650 to the driver, outside of the host for setting the pot. (I feel stupid)

 

[Toke]

Strip the ends of two wires and tape them onto the ends of the battery.

 

[Toaster]

Oh, I thought there was a more elegant solution

 

[Benm]

Point-welding connectios is the elegant solution, but you need to have the gear to do that.

As far as AAA NiMH batteries providing 6 amps of current: its probably the short-circuit current that is being referred to, and most of them easily achieve that.

If you are noticing a drop off within seconds, i recommend you measure the battery voltage at that point. If it has dropped considerably from the specified voltage, the battery is to blame. If the batteries are still near their rated voltage, the driver is to blame.

 

[Toaster]

point welding.... huh sounds difficult. Thank you also, very helpful.

 

[Benm]

It is not very difficult to do, but you need a spot welding machine. I dont like taping wires to the ends of a battery - you can get big contact resistors that way. You could use a battery holder like these: Battery Holders : Recharge RC Radio Control Components Futaba JR Connectors - they come in AA and AAA sizes, and in anything from 2 to about 8 cells.