I need Advice

[Shadar Al'Niende]

So, i recently wired up a Red P4 with a Hasbro FX board. When I initially applied power to the board (touching the switch leads) the LED powered on but then dimmed ridiculously. It was SO dim, that I could look at it directly. I figured maybe my batteries needed charging, so I plugged it in to the charger.

It has not finished charging but I figured I would check it with my multimeter to see what it was running. Here are the readings i got:

Voltage shows as 5.47
Amperage shows as 4.26 with an A on the right hand side of the screen.

I was very confused by this as I should not be giving the LED that much voltage and there is no way that i am giving this thing 4.26 Amps as the Multimeter shows...

I am nervous that I am giving the LED too much Voltage (and subsequently have blown it) and am confused by the reading I got for Amperage. Anyone have any suggestions or ideas?!

I have my 4 AAA NiMH batteries wired with two of them soldered together, + to - each. Then I have a jumper wire running from one "stick's" + to the other "stick's" - This leaves a + and - for leads.

[Arkhan]

Hasbro FX boards are usually in the 1000ma range. A little more, a little less.

I have a luxIII red running at 4.5V on AAA Lithiums, and it has no "power resistor/buckpuck"

Is it possible you burnt it up? sure. "dim" is a good sign of that.

[Shadar Al'Niende]

Yeah, I am guessing I blew it... literally. Thanks.

[RevengeoftheSeth]

Don't bother testing amperage of a battery with a multimeter. It will show you it's max potential to output current. The only way to figure mAh is to constantly measure the battery current and drain it completely, then calculate what the average output was (in mA) and multiply it times the time it took to drain (in hours).

It all depends on the draw of your resistored device (such as an LED). A 2000mAh battery should be about to output 1000mA for 2 hours or 2000mA for 1 hour.

I bet your battery was hot after testing it, too, wasn't it?

[Shadar Al'Niende]

Nope, they felt just fine. And I was not trying to test for mAh, just mA. I wanted to see how much current was feeding to my LED, apparently it was too much.

mAh is a measurement of time, thus the h. (h = hour) I wanted to know how much current was being fed in miliamps (mA) to my LED, i rated it at ~4 Amps which does not seem right to me. I do know the difference between mA and mAh ;)

[FenderBender]

Like I told you before, if you didn't put the meter in series with the LED, you won't get an accurate reading of what it's pulling. When you try and meter in parallel you are essentially creating a short.

P4 reds can sometimes be tempermental with 4.8V packs. Most of the time I end up running them with 3.7V lions

[RevengeoftheSeth]

Nope, they felt just fine. And I was not trying to test for mAh, just mA. I wanted to see how much current was feeding to my LED, apparently it was too much.

mAh is a measurement of time, thus the h. (h = hour) I wanted to know how much current was being fed in miliamps (mA) to my LED, i rated it at ~4 Amps which does not seem right to me. I do know the difference between mA and mAh ;)

Not saying you don't know the difference. I'm saying that if you were trying to test it with a multimeter, you are going to get wacky readings. I elaborated for others who might attempt to do the same.

[Skottsaber]

Just a thought, I remember Do-Clo did Assaj conversions, and I'd ask him if he discovered any wacky behaviour from the Assaj boards.

[Shadar Al'Niende]

Like I told you before, if you didn't put the meter in series with the LED, you won't get an accurate reading of what it's pulling. When you try and meter in parallel you are essentially creating a short.

P4 reds can sometimes be tempermental with 4.8V packs. Most of the time I end up running them with 3.7V lions

Maybe I simply don't understand how to meter current. Can you explain to me where the probes go?


Not saying you don't know the difference. I'm saying that if you were trying to test it with a multimeter, you are going to get wacky readings. I elaborated for others who might attempt to do the same.

I see, thanks. ;)


Just a thought, I remember Do-Clo did Assaj conversions, and I'd ask him if he discovered any wacky behaviour from the Assaj boards.

I don't think its the board... *sigh* I will hopefully order another P4 soon.

[Jay-gon Jinn]

Maybe I simply don't understand how to meter current. Can you explain to me where the probes go?


You'll have to hook up one leg of the main led to the sound board, I usually use the positive side. Turn on the saber. Then, you attach the negative probe to the negative lead for the main led....the positive probe goes to the negative pad on the led. This should give you the measurement for the current the board is outputting while under load.

[PhoenixReborn]

P4 Red + 4.8V + FX Board = Blown P4 Red. You should use Lux3 Red in that case.

[Shadar Al'Niende]

Oh, ok... so that the multimeter completes the circuit?

[Rhyen Skytracker]

I have had many P4 Reds work with that set up in the past, but it seems that here lately they can't handle it. I have had 3 out of 5 blow in the same exact set up.

[Shadar Al'Niende]

That is the advice i was going off by not wiring in a resistor (the working fine thing, not the blowing 3/5 :p) From now on I will just do a resistor, not hard to replace one with a spare piece of wire if it is too dim. *shrug* can't un-blow a blown led....

[Jay-gon Jinn]

Oh, ok... so that the multimeter completes the circuit?

Yup. ;)