Some final help with my first moddification - ALMOST DONE! STILL NEED HELP

Finally I collected all the parts to do my first moddification, but I have some questions.

I am going to mod a Mag 2D with H22A heatsink, DX SKU 7882 driver and SSC P4 led. I Am going to use 3AA NiMH bateries- Now my questions:

1. Should I use the wires included by DX with the driver? or Should I use a different one? What gauge?
2. I tried to insert the heatsink into the body using only my hand and it didn't got in. Is it normal? Should I use some PVC pipe to force it? Should I do some sanding? What should I sand the body or the heatsink?

Thanks in advance for your help

EDITED: Still needing help.

Re: Some final help with my first moddification

1: The wires should be fine, I don't see any reason to change them. You will of course need your own wire to connect the board to your switch.

2: That is great you have such a tight fit, I have done about 10 of these, and only 2 had a really nice fit like that. If you can slather it up with heatsink grease, and pound it in with appropriate size PVC. Since I am not there, I can't tell how tight a fit you have, so you may need to sand the battery tube of the mag. I wouldn't sand the heatsink, did you get the annodized version?

Sku 7882 is a boost driver, I haven't yet played with it. But, I am pretty sure you don't want to run this on 3xAA for two reason's, your voltage will be too high, and besides, why would you want to use such small batteries?

Since you are running a 2D mag, I would suggest you simply stay with 2D batteries. Normally alkaline's can't handle a ton of current, but with big D cells, I would think you will be all right. If it sags too much, then you can try rechargables. Check your battery voltage both under load, and not, and see how much it drops. I would think if it stays at 1.1 or higher you would be ok (under load).

Here is a rather long thread which I am sure could help you.
http://www.cpfmarketplace.com/mp/showthread.php?t=169324

Re: Some final help with my first moddification

Sku 7882 is a boost driver,

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I agree, and I have had a play with them. I've used them with 2D cells and they work fine (as long as you don't get a duff one!) . I would leave the voltage boost adjusting screw pot thing alone. The factory setting is just right for 2 cells. I remember getting around 700mA from two D cells with that set up.

That driver works well with the mag switch, you can half press to change modes until you find the one yoiu want and then fully press the switch ON to lock the mode.

Don't forget to come back and let us know how it goes.

Re: Some final help with my first moddification

Thansk you VegasF6 and Essexman for your replies.

VegasF6 said:

did you get the anodized version?

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Yes, I did. When I try to push it inside the tube with just my hands it doesn't even enter a millimeter. I don't have a caliper to verify the heatsink diameter nor the tube one.

VegasF6 said:

why would you want to use such small batteries?

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Because those are the only rechargeable ones I have and I have a lot. I also have AA to D converters.

Essexman said:

I remember getting around 700mA from two D cells with that set up.

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I would like to get something closer to 1000ma, that is why I want to run it with 3 batteries.

I have another question. I bought Arctic Silver 5 as thermal compound to "stick" the LED to the heatsink; but, in fact Arctic Silver 5 is not an epoxy so the LED won't "stick" to the heatsink. Since I live in a country where this specialised items are difficult to find, Is ok to use what I already have (AS 5)? Could the LED fall from the heatsink and burn due to bad heat transfer?

Re: Some final help with my first moddification

1: Then yes, sand the mag body. You don't want to break the annodize, it is an electrical insulator, otherwise you could short your led.

2: AA will be better with the 2aax1D adapters at least you will double your capacity.

3: I am not trying to be rude, but I don't think you understand how a boost circuit works. Your battery voltage must be lower than the voltage going to your led. For 3 cells, the best thing would be a boost/buck circuit, but I am guessing you are trying to do this on a budget? I don't have a recomendation for a boost/buck that is cheap, it seems many people have tried to find one from places like DX and the choices are very limited, and quality is also. You could use any of the boards offered that use 3 of the amc 7135 linear regulators with 4.5 volts and you will get 1000 mA out, I have done it myself. But, if you search for discussion on these, you will find various opinions. They work fine, but they are just a linear resistor. As soon as your battery voltage is lower than the voltage of your led, they go into direct drive. So, you will have your 1 amp output until your batteries drop to whatever your led voltage is, say 3.7 or so, then you will have less.

With the circuit you chose, you don't get more power by adding batteries. Turning the pot on the board increases the output, but there must be a reason Essexman is suggesting you don't. He has used it and I haven't. Perhaps it is unreliable at higher currents.
Spend some time on the driver thread:
https://www.candlepowerforums.com/threads/188227

And finally, you will need a way to make sure your led stays where you put it, AS5 on it's own won't cut it. You could buy arctic alumina, fuji heatsink (glue like), or if you look around on here, you could find a formula to mix your own with the AS5 you already have and either silicone or epoxy or something.

Re: Some final help with my first moddification

VegasF6 said:

1: Then yes, sand the mag body. You don't want to break the annodize, it is an electrical insulator, otherwise you could short your led.

Click to expand...

I already sanded the Mag body with # 220 metal sand. I tried again and now the heatsink fits a little better. Did not try to completely insert it.

VegasF6 said:

2: AA will be better with the 2aax1D adapters at least you will double your capacity.

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Yes, I thought about those for my next mod (SoShine 2xAA to D-Size Cell Battery Converter). A Maglite 3D with SSC P7, DX SKU 7612 (3AMD 7135 + levels driver) + DX SKU 1886 (4 AMD) 7135 drivers and H22A P7 heatsink. Only LED missing. I am going to buy it from PhotonFanatic in CPFMP.

VegasF6 said:

3: I am not trying to be rude, but I don't think you understand how a boost circuit works.

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Don't worry. You are right. But StefanFS has used this driver with Li-Ion Protected batteries with success. He recommended it to me.

VegasF6 said:

but I am guessing you are trying to do this on a budget?

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Not at all. The problem I have when buying from USA is that I have to pay a lot for S&H. I have the option to buy items delivered to a courier service in Miami that bring things to me to El Salvador. But it is an expensive service. Just as an example: when I bought my Fenix Pack (P2D Q5 + L1D body) I paid something closed to $ 35 for transportation to El Salvador + customs services + duties. KD/DX is not the best option neither. I waited more than 2 months to get the driver from DX because of "Waiting from suppliers".

VegasF6 said:

And finally, you will need a way to make sure your led stays where you put it, AS5 on it's own won't cut it. You could buy arctic alumina, fuji heatsink (glue like), or if you look around on here, you could find a formula to mix your own with the AS5 you already have and either silicone or epoxy or something.

Click to expand...

Since I don't have anything else I guess I am going to use the "hair+super glue" method described here

Thank you for your help.

Re: Some final help with my first moddification

I decided it was finally time to break out this circuit and see what I could do with it.
On one battery it ain't worth a crap, as has been mentioned before.

One 2 cells, I am pretty happy with it so far!
I am running it on 2 LSD D cells, that have some use on them, but voltage checked at about 1.3 per cell before starting (I have no way to check the cells actual charge level other than voltage though.)

I did have to adjust the pot some to get what I wanted, but here are my results:

Batt under load Led (Q5 on star WC color)
V A V A
2.51 2.08 3.57 .97

I had it cranked up a hair higher with amp reading to the led at about 1.04 and the board felt pretty hot in my hand, I cranked it back the least little bit to .97 and it has been running for 25 minutes so far, seems cool enough.

It would be great if someone could do the math on the efficiency here, but it looks to be in the 60% neighborhood??

I didn't try with 3 cells, as I said, I am not quite sure about running a boost circuit at those higher voltages, I imagine it just defaults to direct drive.

*edit* because of my terrible photos you cant read all the meters at once, but if you do try, here is the order they are in.
1:Led voltage
2:Led amperage
3:Battery voltage
4:Battery amperage

My battery voltage has dropped some in the 25 minutes, and my amp reading at the led is now closer to .94, so if this is supposed to be constant voltage or constant current circuit, it isn't doing a spectacular job of it, but it will run pretty good on 2.5 volts.

My images are larger than the 800x600 rule imposed here, so I am posting a link to my box with them so you can look.
http://www.box.net/shared/4x7kpoesc4

Re: Some final help with my first moddification

I terminated this test after 1 hour, I shoulda used smaller batteries, this thing will run forever.

After 60 mins:
Batt under load Led (Q5 on star WC color)
V A V A
2.46 2.04 3.58 .93

I am not sure on my math, but if correct I had 66% efficiency. Not great, but not too terrible.

Re: Some final help with my first moddification

Thank you VegasF6 for your tests.

I am going to run it on 2 batteries and see what I get.

From your readings I guess I will not get more than one hour with 2600 NiMh AA's. But with 2 AA pairs in parallel I guess it will last longer.

Re: Some final help with my first moddification

Put the heatsink into the fridge and heat up the magtube.

Then it will fit. but be carefull. Once done you won't get it disambled again.

Re: Some final help with my first moddification

Der Wichtel said:

Put the heatsink into the fridge and heat up the magtube.

Then it will fit. but be carefull. Once done you won't get it disembled again.

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This was exactly I going to write when I came back to this thread. This morning when I tried to insert the heatsink into the body it went in. The heatsink and the body were cool. I was thinking to do exactly what you are recommending me. Anyway I already sanded the body and the anodisation was pealed. Now I can see the aliminum.

Thank you.

Re: Some final help with my first moddification - DONE!

I finished my first mod.

It pulls 160ma on low, 1300ma on medium and 3100ma on high from 2xAA Sanyo Eneloops. Cannot tell with strobe because I am using a Fluke 179 DMM and not an oscilloscope.

In high it gives 900ma to the LED. Unfortunately I didn't measure voltage to the LED before assembling.

I will post pictures soon.

Thanks for your help.

Juan C.

Re: Some final help with my first moddification - DONE!

3,1A is a little bit much, isn't it?

Re: Some final help with my first moddification - DONE!

Der Wichtel said:

3,1A is a little bit much, isn't it?

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Yes, I think so. But what could I have done wrong? Do you think I should do anything else to fix it?

What could happen if I run my light in that conditions?

EDITED.

One more question: Could I have turned the pot to an incorrect position?

Re: Some final help with my first moddification - DONE!

can you measure the voltage or current on the led?

Re: Some final help with my first moddification - DONE!

When pulling 3.2A from batteries I got 3.4V and 900ma at the emitter. When pulling 1.6A from the batteries (I moved the pot until I got this reading) the voltage at the LED is 3.3v, the current 650ma.

I have disassembled it more than 6 times today playing with current pulled from the batteries but something is wrong with my measurements. When I measured disassembled I got 1.5A from the batteries, but once reassembled I got 2.8A, so I decided to leave it pulling 1.2A from batteries disassembled but when assembled I got 1.6A. I am going to test it tonight. Probably I will no be as bright as I wanted, but will be good.

Since this is the only 7882 circuit I have on hand and I don't want to fry it, I decided to lower the current from the batteries.

I glued the driver to the switch body using hot melted silicone (I don't how is it called in English. Is one of those electric devices used by woman - some men also use it - in home to glue things). Could it melt with the driver heat and the driver fall?

Re: Some final help with my first moddification - DONE!

It's called a hot glue gun. I don't know if I would recommend that but wikipedia has some information on the melt temps, you should be well under that.
http://en.wikipedia.org/wiki/Hot_Glue

Resistance in your switch assembly could be responsible for a little of the difference in your current readings, but I certainly wouldn't think THAT much!

It isn't shorting out to the side of the light anywhere? Those readings sound very high, and I can't explain why they change so much in the light. Is that after a very long run time when the inside of the light is heating up, or almost instantly?

Re: Some final help with my first moddification - DONE!

VegasF6 said:

It's called a hot glue gun.

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That you for the name

VegasF6 said:

I don't know if I would recommend that but wikipedia has some information on the melt temps, you should be well under that.
http://en.wikipedia.org/wiki/Hot_Glue

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Apparently the melting temperature for the low heat one is 120ºC (250F). Could the driver reach that high temperature? Wouldn't it fry first?

VegasF6 said:

It isn't shorting out to the side of the light anywhere?

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In fact all the modes work pretty fine. I don't think there is a short anywhere. Probably I am not doing good contacts when testing disassembled.

VegasF6 said:

Is that after a very long run time when the inside of the light is heating up, or almost instantly?

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It is instantaneous. I have not run the light for more than 5 continuous minutes.

I tried the light this night and I can say it is not any special. I don't have a light meter, but if Fenix L2D on turbo is 180lm I think it is not more than 160lm. It throws good; even better than my Romisen RC-W4 on high with Ultrafire 17500 Li-Ion battery (better throw but no better overall).

Re: Some final help with my first moddification - DONE!

I think your driver is defect. I have the same and it does not take that much current

Re: Some final help with my first moddification

VegasF6 said:

I terminated this test after 1 hour, I shoulda used smaller batteries, this thing will run forever.

After 60 mins:
Batt under load Led (Q5 on star WC color)
V A V A
2.46 2.04 3.58 .93

I am not sure on my math, but if correct I had 66% efficiency. Not great, but not too terrible.

Click to expand...

In this image:



The biggest cut (the raised one) of the pot is facing to the right (toward R1). Where is that one pointing in your driver?