Moonlight special w/ 11x AMC7135 only getting 2.3A? (SOLVED)

Hello friends, I am trying to finish up a build for my fathers bday gift. His surprise party is this Sunday, so I don’t have much more time. (If I have to I can gift it and then ask for it back to finish but ehhh…)

I have a moonlight special driver build by Richard. It is powering a XML2 U2 1A emitter. From the start, I have not been able to pull more than 2.3A on turbo. The board has a total of 11 AMC7135’s so I should be able to get close to 4A. Can someone suggest a solution?

The driver has 5 modes (Moon—->10—>30—50—>75—>100%
Turbo Timer 60 sec with Mode memory.

At first I thought is was because of the host sk98. I tried another Convoy M1 type host. Same number-2.3a. I’ve also wired it strait to the battery. Same number. I’ve tried to give the relevant information, but let me know what else you may need to know.

Does anyone have a suggestion?

Among other things, to the measurements you need to use a electric wire with a good thickness.
I use this, is 4mm²:

what battery are you using?

Thanks for the replys!
I am using Samsung 25r

I am using a sperry multimeter with aftermarket thicker leads. Idk the gauge but I would think they would be sufficient?

Have you tried connecting the cell directly to the LED ( while it is well heatsinked) to see what current you get? If you connect battery to battery tube, is it brighter than when you measure with the DMM?

On a very similar build the standard leads on my multimeter compared to the 4mm2 copper leads 200mm long which I made up gave an increase in the reading obtained on the multimeter of approx 0.5 amps, I didn’t expect it to be that much of a difference.

I have not connected the LED straight to the battery bypassing the driver. Can I do that?

I did not take note if it was brighter with the battery tube than when connected to the DMM. I will try that this evening.

Also, I will make my own test leads. I have some 12 awg speaker wire and I will keep the leads short. I think that should be thick enough?

I will report back what I find.

Did you add the extra chips or did Richard? I’m pretty sure he would have tested it. I think most of us who have done chip stacking have at some point experienced this. Since you have a meter you can test each stack for continuity to it’s respective connection. Output pin to led-, ground to ground ring, pwm pin to pin 5 or 6. The moonlight special has one 7135 connected to one of those and the other seven connected to the other. It’s also possible to kill them with too much heat.

Yes, 12AWG are about 3.3mm², for your class measuring okay! Do it short, just long enough.

Thanks friends. I made some new leads. They are 14awg and 150mm long. I retested and I get a boost of .5amps. That puts the total up to 2.8A

This is better but still a ways from 4A. Do you think it could still be my meter set up? I made the test leads out of some cheep banana plugs. Maybe this adds some resistence? But I wouldn’t think so.

I have a few XML-2 U2 leds that have very high fV. This well may be the problem.

Is there a way to measure this? Can I connect directly to the battery through an amp meter and then measure the colts at the same time? Idk if this will give me any useful data?

If I connect directly to a fully charged Samsung 25r and measure the amps and it still only reads 3-4amps, could I conclude that the driver is fine because the LED is just not pulling the amps?

If so maybe I could get a 3.8v battery and give that a try. I have a compatable charger already.

To measure the Vf of the emitter just set the meter to DC volts and touch the probes to the led+/- pads and tell us what it reads. With the light on.

These high fV XML-2 leds also could not take high currents. From memory they were only reliable up to about 5 amps before they let out the magic smoke. This was powering then directly from my power supply.

I decided to swap out the emitter and take a reading with another xml2 t6 5a emitter that I had. The results were actually lower amps yet.

The U2 pulled 2.3a with the standard leads from my meter. 2.8a with the beefed up leads.
The t6 2.2a and 2.6a respectively.

I also tested an Olight s30 that I just got in the mail to see if my meter is working correctly. I got a reading of 2.9amps at the tail cap. So, I don’t think it is my meter and it doesn’t seem like it is the emitter as well. I’m thinking some is not working correctly with this driver. IDK?

I will swap back emitters and take a vf reading.

Thanks for the help friends!

I have tried and tested many ideas now and I cannot get over 2.8Amps with this driver. IDK what else to try? I guess it is decent bright and I like the driver anyway, so maybe I will just settle with this.

If anyone has any more suggestions let me know.

Ps. It is for sure notice meter. I have tested it and used it to test some other drivers and it is spot on down to .1Amps for sure.

Have you only measured the S30? or have you measured any other lights over 3amps?

It very well could still be your meter. It’s not that the meter is wrong, but instead that the meter is causing some resistance that makes the current be lower.

I’m not sure, but the S30 might have a boost driver like the S1 has, which has the ability to compensate for the extra resistance and give you a better reading. Just a thought.

dumb question. have you confirmed that 11 chips are in place?

not seeing things it sounds like it has the standard 8?

Maybe you need to play “which three chips are not like the others?”

Connect the battery directly to the led and measure the amps

I don’t have any lights that pull more than 3amps-not yet;)
I’ve also tested a convoy s3 and s2+ each with 8 chips. They measured 2.73 and 2.78amps respectively.

The board does have 11 chips.

I have been hesitant to connect directly to the battery, but that has been suggested a couple times so I will do that tonight. Then if my meter still reads under 3 then maybe my meter will not go above 3amps? We will see. I have an amp meter from Richard on the way so I can test with that when it gets here.