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Best Driver to Push 500mw Mitsubishi off single 3.7v Li-Ion Cell.

A

Arcygenical

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So, I've done a lot of resarch about this, and I'm wondering if anyone has any first-hand recomendations.

I'm putting together a mini 638nm pointer, hoping to get around 500mw from it (nothing too crazy, for battery charge lifetime) but I'll be powering it with a single 3.7v protected li-ion cell. I was hoping to use a Flexdrive V5, but these are increasingly hard to come-by in Canada.

A related question, as I've never done anything but put modules in hosts before... Assuming I can get my hands on one; If I set the flex-drive output current to the 4th position (455ma-1.1a) and set the pot to it's lowest setting, the voltage output should match the diode's requirement at the minimum 455ma current output, correct? Since it's a constant current output, the voltage put out should simply be the voltage required by the diode, no other adjustment is necessary. Am I correct in this? Actually, after a bit more reading, this does seem to be correct. The driver will vary the voltage to allow the diode to pull whichever current setting is selected, IIRC.

And for a second slightly related question... I'm looking for a very solid red beam for night-time visibility. Is there a massive difference between the 300mw mitsubishi's and the 500mw ones for beam visibility? I'd feel safer playing with a lower mw diode (even with glasses) over a higher one. Visibility is key here, though. If the difference is substantial, I'll just be even more careful.

Sorry for the somewhat beginner questions. I've been doing a ton of reading recently, but I've never really experimented with hooking up my own drivers, and my electronics knowledge is that of a hobbyist. Any help is greatly appreciated.

Cheers!
 
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Well, the best thing to do would be (assuming that you get a flexdrive) to set it as you originally planned, and hook it up to a test load. Once it is hooked up to the test load, you turn the pot and check the reading in mV across the 1ohm resistor and that should equal mA due to ohms law. Once the reading of mV is where you want it (in your case maybe 500-550mA) you remove the test load and solder the driver leads to the pins of your diode, which should already be pressed into its module. Then you just assemble and hope you didn't mess up somewhere. Hope this could put some perspective on things, I'm always trying to please :D! Good luck with that laser! $110 diode, ouch! :beer:
 
Yeah, that's what I was thinking of doing. Setting up a cheap dummy load and testing it that way. I actually am looking for lower output, since i"ll likely be using a 10440 3.7v. I'd like to get a full hour run time out of the ~500mah battery.

And I know, 110$ diodes are downright pricey... One reason why I'm looking into the 300mw version!
 
Well you stated in the OP that you were aiming for 500mW, so I suggeted a range that might give that output. If you might switch down to the 350mW diode, then the Amps involved may be different. I haven't had the pleasure of working with one of these yet, so I wouldn't know honestly what a decent current would be for the 350 diode. If you have any more questions I'll see what I can do. Reading around in the "Red Lasers" Section of the forum should lead you to a wealth of information if you give some effort looking.
 
You can use an AMC7135 driver for a single cell configuration.
I have build 3x AMC7135 driver for 1060mA current for my 300mW Mitsubishi diode and it went well. Now I have removed one ic for a lower current of 700mA. I want a conservative setting for longer runtime. The build was in the C6 host and the heatsink was electrically isolated from the anodized host.
 
Blord said:
You can use an AMC7135 driver for a single cell configuration.
I have build 3x AMC7135 driver for 1060mA current for my 300mW Mitsubishi diode and it went well. Now I have removed one ic for a lower current of 700mA. I want a conservative setting for longer runtime. The build was in the C6 host and the heatsink was electrically isolated from the anodized host.
Click to expand...

Subject change, but does this confirm for me that the C6 host using an anodized heat sink as well is electrically isolated from the batteries? I've been meaning to make a C6 Mits laser but I feared that since the case pin is (-), if it wasn't isolated that it would short and poof. :beer:
 
You can measure with a DMM the resistance between the C6 heatsink and the host. My C6 shows no electrical path between these components. Always test before hooking up the stuff. Of course the heatsink must be short enough not to touch the pill.
Btw it is the host that is standard anodize. The sink is just bare.

Lucky none of this apply to the 300/500mW Mitsubishi diode because the diode is already case neutral.
 
Blord said:
You can measure with a DMM the resistance between the C6 heatsink and the host. My C6 shows no electrical path between these components. Always test before hooking up the stuff. Of course the heatsink must be short enough not to touch the pill.
Btw it is the host that is standard anodize. The sink is just bare.

Lucky none of this apply to the 300/500mW Mitsubishi diode because the diode is already case neutral.
Click to expand...

Yes, I understand that I should always test, but in my case, the host AND heat sink are anodized. Funny huh?
 
I just baught some buck boost from foulmist in Bulgaria.
The diode is rated 2.6V max so you need a buck.. or linear. I just got my 2nd diode today and have been playing with it again on the PSU being alot more carefull and I have been getting about 1W out with a G2 on an average at 1700ma. took it to 1950ma for a 1 min run. I didnt kill it yet... I havent seen any flexdrives for sale if you find some let me know...
 
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Blord said:
You can use an AMC7135 driver for a single cell configuration.
I have build 3x AMC7135 driver for 1060mA current for my 300mW Mitsubishi diode and it went well. Now I have removed one ic for a lower current of 700mA. I want a conservative setting for longer runtime. The build was in the C6 host and the heatsink was electrically isolated from the anodized host.
Click to expand...

Very interesting. I think I'll take one of the IC's off as well. No other modifications necessary? 700ma would be perfect for my intended application. Cheap driver as well.
 
Arcygenical said:
If I set the flex-drive output current to the 4th position (455ma-1.1a) and set the pot to it's lowest setting, the voltage output should match the diode's requirement at the minimum 455ma current output, correct?
Click to expand...

Just an FYI for when the flexdrive becomes available again or when someone clones it

The pot on the flexdrive does NOT have "hard stops" on its pot.
You cannot just "set it to its lowest setting"
It will spin right past the lowest setting onto the highest setting

You must either use a test load to set the current
or
connect it to the diode and adjust it for the power output (mW) desired using an LPM

Connecting it to the diode to adjust for output can be dangerous with the flexdrive
The pot is very sensitive
It has been known to jump around SIGNIFICANTLY :(

Peace,
dave
 
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^ Thank you for that. I was just going to use a DMM to find the cutoffs for the pot, but the AMC7135 is looking like a better option - I can't find the flex anywhere, and I absolutely need to use a single cell for power - Can't use a buck.
 
Arcygenical said:
Very interesting. I think I'll take one of the IC's off as well. No other modifications necessary? 700ma would be perfect for my intended application. Cheap driver as well.
Click to expand...

Just remove the ic. They are parallel connected so no modification is needed.
Each AMC7135 counts for 350mA.
 
Blord is on the money, you can get all different mode versions of these AMC7135s too.

My personal favorite is the 16 mode driver

you can get 3 groups of modes. that you can easily change between.

1) Low / Med / High / Strobe / SOS
2) Low / Med / High
3) Low / Med / High / Strobe / Police Strobe / Slow blink (3Hz) / Slow blink (1Hz) / SOS
 
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