parallel drivers

^ No, that is using them in series. What DrLava was describing is using them in parallel. So + from the battery to the + on both drivers battery connections and - from battery to - on both drivers battery connections. Then + from both drivers to the + of the laser diode and - from both drivers to the - of the laser diode. Make sure to short the outputs of both drivers(temporarily) before hooking up the laser diode or that will kill the laser diode.

Then how do you power each driver or does it require 2 batts?

I don't think you neet 2 flex for 1.4A
Nospin has one that runs at 1.5A
Look at that: http://laserpointerforums.com/f65/merged-445nm-pictures-video-thread-51335-23.html#post731380

One fully charged 18650.

SpyderFire said:

Then how do you power each driver or does it require 2 batts?

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millirad said:

One fully charged 18650.

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Make that one high quality fully charged 18650... those darn cheap-o UltraFire 3000mah batteries are only good for around 700mA.

I have been wondering about making a small driver for a flash light with 2 lm317.
It would be really convenient if they could use the same current set pot meter.
Have anyone tried?

ETA:
I have been reading up on the lm317, and yes it can be connected in parallel.
The problem comes with the current setting resistor/trimmer, it takes the full current to create the 1,2V drop for regulating the lm317.
That is a pretty big trimmer pot.

AdamCaudill said:

I'm going to attempt parallel drivers in my next 445 build to deal with that; hopefully it'll work as intended (it should, in theory at least).

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DTR said:

So the idea is if I set up say two microboost or flexdrives set to 850mA in parallel it would give me 1700mA? That would be neat. Would both drivers run off one battery or would you want two separate power batteries one driving each?

If this works I have my next project.

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AdamCaudill said:

Yep, that's the idea. Take a look at this thread for some more details. I was hoping to use this method to beat your beast, but I'm unless work lets up and gives me some freetime soon, you'll probably beat me to it

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DTR said:

Well you have definitely peaked my interest which I will note if I get it up and running. I see a handheld in my future set to 1.7A Now for the fun. This method may also reduce the heat issue with the drivers when running at 1.5A.

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AdamCaudill said:

I'm really hoping that's the case, as the diode will be generating plenty of heat at that power. Otherwise, may have to add a small fan or something of that nature to keep the heat in check.

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If it would relieve the need for a heatsink on the driver that would be great.
I think I will set them to 825mA each with a combined 1650mA and see how the diode holds up. I have a MXDL with a pretty large heat sink for the diode that I think will be good plus there is a lot of room in the host for the two drivers.

DTR said:

If it would relieve the need for a heatsink on the driver that would be great.

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My plan was to use thermal tape to attach the drivers to the side walls of the host, thus using the host itself as a heatsink. To get enough space to do this, I'm going to have a custom host mode - which is my biggest holdup at this point. I just hope my assumptions about the reduced heat output are correct, as I really don't want to resort to some auxiliary cooling method (fan, etc).

DTR said:

I think I will set them to 825mA each with a combined 1650mA and see how the diode holds up.

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With as tough as these diodes are, I think as long as you keep the duty cycle short (<60, though <30 would be better) and have a setup that is as heat efficient as possible (perhaps a large direct press heatsink) they should be able to take a lot of power. I'm planning on setting mine to 900mA, so that's 1800mA going to the diode; looking at what they are ran at in the projector I see no reason that this power level would be an issue.

It will shorten the life of the diode, but if I get a total life of more than a couple hours, I'll still be happy. This is meant to be an experiment in power, nothing more.

DTR said:

I have a MXDL with a pretty large heat sink for the diode that I think will be good plus there is a lot of room in the host for the two drivers.

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That's the DX 3405 isn't it? I've got a couple of those with jayrob's heatsinks; not pretty but a great host. My only complaints for this application would be 1) not being able to attach the drivers to the sidewalls as I'd like to and 2) the 10440 batteries; I'm really not sure if they could put out enough power.

With 10440's, I'm assuming you would run those in parallel (didn't I see that you have a setup like that?) which I'm just not sure if they could supply enough power. I'm thinking that an AW or another higher end brand 18650 would be a better choice for this application. Between the drivers and 1.7+A to the diode, that's a lot of load.

AdamCaudill said:

That's the DX 3405 isn't it? I've got a couple of those with jayrob's heatsinks; not pretty but a great host. My only complaints for this application would be 1) not being able to attach the drivers to the sidewalls as I'd like to and 2) the 10440 batteries; I'm really not sure if they could put out enough power.

With 10440's, I'm assuming you would run those in parallel (didn't I see that you have a setup like that?) which I'm just not sure if they could supply enough power. I'm thinking that an AW or another higher end brand 18650 would be a better choice for this application. Between the drivers and 1.7+A to the diode, that's a lot of load.

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It is unbelievably ironic that you mentioned that. After my last post I finally dove in and modified my 3405 to use a 18650. Took all of five minutes. All you have to do is take out the plastic retainer by using a drill to cut it out. Then put a blob of solder on the side contact point on the switch and press it in. It works great and the cap screws down to the perfect tight point.





Here on the Clicky switch just put a blob of solder on the contact point(marked in yellow) for a snug fit and use something to press it into the tailcap.


And there you have it a perfect fit for a 18650 battery.

DTR said:

It is unbelievably ironic that you mentioned that. After my last post I finally dove in and modified my 3405 to use a 18650. Took all of five minutes.

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In that case, I would say that the 3405 is a much more viable option. Looking at a 3405 that I have that's mid-way through a build, I'm thinking there are a couple possibilities for mounting the drivers:

1. Side of the pill - I'm not sure if this will work (don't have a driver handy to confirm the size), but you might be able mount the drivers to the inner walls of the pill to use it as a heatsink. I don't think this will work as well as mounting to the inner walls of the host itself, but at least with the heatsink I have, there isn't room between the pill and the bottom of the heatsink to put anything.
2. Stacked with smaller heatsinks inside the pill - Might be able to use two small heatsinks, so you'll have (from the bottom up) heatsink -> driver -> heatsink -> driver. The heatsinks couldn't be very thick, but should give decent performance.

I think I'd try option one first, as it eliminates two custom parts from the build. The really nice thing about this, the heatsink has a lot of mass, so it should deal with the heat quite well.

AdamCaudill said:

In that case, I would say that the 3405 is a much more viable option. Looking at a 3405 that I have that's mid-way through a build, I'm thinking there are a couple possibilities for mounting the drivers:

1. Side of the pill - I'm not sure if this will work (don't have a driver handy to confirm the size), but you might be able mount the drivers to the inner walls of the pill to use it as a heatsink. I don't think this will work as well as mounting to the inner walls of the host itself, but at least with the heatsink I have, there isn't room between the pill and the bottom of the heatsink to put anything.
2. Stacked with smaller heatsinks inside the pill - Might be able to use two small heatsinks, so you'll have (from the bottom up) heatsink -> driver -> heatsink -> driver. The heatsinks couldn't be very thick, but should give decent performance.

I think I'd try option one first, as it eliminates two custom parts from the build. The really nice thing about this, the heatsink has a lot of mass, so it should deal with the heat quite well.

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If the drivers are really only running like they were in a single driver unit running at 900mA then I don't think that we would need to go too nuts trying to sink them. But I was thinking that a heatsink the size of the one in the Beast but instead of being mounted in the pill have the second driver attached on the other side of the heatsink. At that point I will just wrap it up in electrical tape but you could use adhesive on the thin side of the heatsink to stick it to the wall or something.

DTR said:

If the drivers are really only running like they were in a single driver unit running at 900mA then I don't think that we would need to go too nuts trying to sink them.

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With the amount of heat being generated by the diode at higher power, my thought is that it's worth the effort to get as much heat out as possible. Might be overkill, probably won't know for sure until some testing is done.

DTR said:

But I was thinking that a heatsink the size of the one in the Beast but instead of being mounted in the pill have the second driver attached on the other side of the heatsink. At that point I will just wrap it up in electrical tape...

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That's a good idea, and should get the job done quite nicely.

This is going to be one hell of a build; should be very impressive.

Ok I got two microboost's today running at 850mA each set up in parallel in my MXDL with a single 18650. It is very bright for about 3 second and then starts flashing. I do not have a fully charged batter here at work with me. When I get home in a few hours I will slap in a fully charged one that I have in the charger right now and see if it works. If it does not I might be on the lookout for a host that can fit two 18500.

You must work at a job like me with free time to tinker lol. No variable power supplies there to bypass using a battery?

cd520 said:

You must work at a job like me with free time to tinker lol. No variable power supplies there to bypass using a battery?

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The Job is nice but long hours. Lot of down time where I can slip into one of my offices and get some personal stuff done. No power supplies but I do have workbenches and a lot of tools at my disposal. I am looking into getting a variable power supply with a digital readout for testing some of my new toys.

just a thought. you should simplify and just get a flexdrive v5. i have one @ 1600ma. on a single 18650

michael