268mW 6X Key Chain Blu-ray! (With FlexDrive!) - Awesome!

[LarryDFW]

Re: Key Chain Blu-ray... With FlexDrive!

Jay & Igor;

I use hundreds of lithium ion batteries a year in UV LED & LD portables lights I build.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1231740101

None of them utilize a protection circuit, and the failure rate is almost nil.

The best advice I can give to you is to utilize a HIGH-QUALITY li-ion cell.

I have had excellent results with Sanyo, Sony and Panasonic cells.

I prefer the #18650 size batteries, but for smaller builds you can look at the 14500's or smaller.

Smaller types than the 14500 will be more difficult to source.

Larry DFW

 

[jayrob]

Re: Key Chain Blu-ray... With FlexDrive!

Thanks for all the good input guys!

Tech_Junkie, that little host is super tiny! It probably doesn't even have a switch! Maybe a 'twist on'. I really don't see (at this point), getting a high powered build with driver into anything smaller than this key chain host here...

About shipping, I sent your package on Tuesday evening from CA, it normally would have got there by today, but I'm sure you will see it on Monday.







LarryDFW, take a quick look at the very first post in this thread to see what all this talk about battery size and capacity is all about!








Igor, I just got your e-mail... I thought it would be a simple matter of whether it fits or not, but now I see there is much more to it! I will be waiting until you do some testing...









danq, thanks for the thought! Keep your eyes out. I'm going to start looking for a tiny circuit too...
Jay

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

I prefer the #18650 size batteries, but for smaller builds you can look at the 14500's or smaller.

Smaller types than the 14500 will be more difficult to source.

Larry DFW

Larry, if you click at my signature, you will see that my "big" lasers use the 14500 battery..  ;D
And people are surprised how small they are when they see them, they say they look smaller than in the pictures... But in comparison to what we're doing here in this thread, my 14500 powered lasers are HUGE..

I call a 10440 powered laser "Tiny", so these here should probably be called "Micro" builds... It's a whole different level. And with batteries of such a low capacity, and drivers capable of discharging them to 2.4 or even 2V, i think protection might be beneficial. It definitelly wouldn't hurt.


What kind of driver do you use, that it doesn't damage unprotected cells by underdischarging, BTW? Or are you saying, that you underdischarge them all the time, but there are no bad results?

The consequence i am worried about is loss of capacity. The batteries for these micro builds may not be available anymore in a year. So i would want them to live as long as they possibly can..



Jay: Since it would seem i won't need the 10180's for my hosts, i would ask you, if you could send them to me sooner (with them labels too), cos i will likelly need them for another project.


As for the protection circuit i am getting - if it has no current-limit-shutdown, then i can make it work in blu rays, as i explained in the email. But reds could present a problem. Unless this circuit works the opposite way from the ones in round batteries (which interrupt the negative side).

This is the smallest protection circuit there is - 10x5mm. I've seen the ones DanQ mentioned.. A battery page sells two different circuits. One is round, obviously from a big round cell, maybe 18650, the other is rectangular and long.. Both are quite large, IIRC.

Those would be possible to incorporate into a blu ray, since their current limit would be higher, but they are probably too big for tiny builds, and it's tiny builds, where we need them. For now i'm hoping this tiny circuit i am getting won't shut down the moment i turn a laser ON.. I should ask AW if he has any specs on it...

 

[danq]

Re: Key Chain Blu-ray... With FlexDrive!

danq, thanks for the thought! Keep your eyes out. I'm going to start looking for a tiny circuit too...Jay

Couldn't we just make one? anybody have a circuit diagram?
it would be cool to just build it into the build, so to speak ;-)

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

Well, i'm guessing there should be Li-Ion protection ICs out there... Something, that barelly needs any external components. Basically we would just need to find the datasheet.

But if the tiny circuit i'm getting will work, it would be the simplest solution. I will look into the ICs tho, if i can find some time...


EDIT: Indeed, i already found 37.600 hits.. Just google "Li-Ion Protection IC"..
Most are way too complex tho. Made for multiple cells with cell balancing and such. We need the simplest single cell solution....

Problem is, the protection IC alone could end up costing more than the protection circuit i'm getting. You know what components are priced like, when you only buy a few - it could cost as much as buying a protected battery and ripping the circuit out! That's why i asked AW about it. He uses them, so he goes through many and gets them cheap.... I think that's the best bet..



EDIT EDIT: I think this is the circuit you saw once: http://www.all-battery.com/protectioncircuitmodulepcbfor37vli-polymerbattery85alimit-pcb1s.aspx

Its a little big tho..  ;D Probably meant to be integrated on the side of a phone battery. And as i feared, it disconnects the negative side - that wouldn't work with case negative diodes....




Here is a nice tiny single cell protection IC: http://pdf1.alldatasheet.com/datasheet-pdf/view/116931/SII/S-8261.html

Costs only 30 cents... If you buy 10.000...


And another one: http://www.siliconstandard.com/Documents/SS6821.pdf

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

This page has complete circuits, for different Li-Ion cells or cell-packs: http://www.aplusproducts.com/gallery/products/batteries/protection_modules.pdf

Not sure if any of them is as small as what i'm getting from AW (10x5mm)... I'm reading through it now.



Problem is, all these circuits are made to be incorporated into the battery, NOT into a device. So there will be problems asociated with this.

All circuits would seem to be made to interrupt the negative battery side, when a certain event triggers them. If you look at the bottom of a protected cell, you don't see the bottom of the battery, but the bottom of the protection PCB. It's between the battery and the outside world. When it triggers, the negative side is disconnected, while the positive is left alone. The circuit also needs contact to both battery terminals to work at all, so protected batteries have a flat cable going from the circuit up to the positive side, under the wrapper... But our batteries are too small, that's why they are not protected in the first place..

The integration problem comes from the fact that the circuits interrupt the negative side. If you put this circuit into a laser, you would put it next to the driver.. Then you connect it to both the positive and the negative battery contact.. Then you connect the driver through this circuit.

But the problem is, the entire laser body is already at battery negative potential, and so is the diode can.

If the diode is a floating pin 405nm, this doesn't cause any problems (as long as you don't short the can pin to negative pin!).. If the protection circuit shuts down, the driver won't get power, and the laser won't be able to work. The protection will protect the battery from underdischarging.

But if the diode is a 660nm, it is case negative. Even if the circuit interrupts the negative input to the driver, the driver still gets the negative battery contact through the diode itself! When making a red, the negative input wire is not even required, with common GND drivers and case negative diodes. You just need to solder the driver to the diode positive and negative, and on the driver's input side, you only need the positive battery contact - that's three connections total required... The negative input is already connected as soon as the driver's negative output is soldered to the diode, since on common GND drivers, the negative input and output are one and the same and the diode is at battery negative potential, just like the entire host....

This means the protection circuit would be interrupting a connection, that is not even required.. It wouldn't do anything, and the driver would keep working and possibly damage the diode.


The same thing would of course happen, when you short the 405nm diode's case pin to the negative pin, to make it case-negative, to avoid the need for the negative driver input connection..


So in most cases, these circuits would only work with blu rays..

There the connections for a protected build would be like this:
- Standard build, laser body at battery negative potential (common GND)
- Protection PCB positive input connected to battery positive contact
- Protection PCB negative input connected to diode case pin for negative battery contact (or anything else in contact with host)
- Driver positive input connected to battery positive contact (directly)
- Driver negative input connected to protection PCB negative output (for driver to get negative battery contact, when protection allows it)
- Driver outputs connected to the floating diode pins (diode pins left FLOATING!)


This would result in a build, that would not allow the battery to be discharged too low...


Doing the same with reds might be impossible, at least with standard PCBs.... There the same PCBs would only work on the battery directly...

 

[danq]

Re: Key Chain Blu-ray... With FlexDrive!

ummm... why not just make some tiny prot boards for the little batteries? Too thick?
There are sot-23 chips that need only a few sm parts to work - circuit below for the first one I saw.  That chip is just a bit more than a mm high.

DanQ

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

I saw this circuit, but it also interrupts the negative side. We can get circuits like that for cheap in 10x5mm.

Making a circuit would only make sense if the samples i am getting consider the current draw of a flex a a short (since they are meant for bluetooth and MP3 batteries).

Another reason to make a circuit would be, if it could be made to disconnect the positive side, instead of the negative.... Then it could be used in both blu rays and reds..

 

[SenKat_Stonetek]

Re: Key Chain Blu-ray... With FlexDrive!

WOW - I can't believe I am just now seeing this thread - Jay...I hate you ! Not really...okay maybe just a little bit ! That looks NICE - that's the lamest description, I know - but the only thing that fits ! Damned fine work (again) !!

 

[jayrob]

Re: Key Chain Blu-ray... With FlexDrive!

Ha ha! ;D

Thanks Greg... It would have to be something special to catch your eye!






Hey Igor, I just turned my red key chain build up to 275mA's, and even at that current, I still get 200mW's using the Sony/Senkat 1239JL-54 diode along with the special AR coated lens that you showed me from flee-bay!

Here's the lenses for red - Just to let others know, you'll get 20 or 25mW's more with these, and they fit right into the AixiZ module!:
http://cgi.ebay.ca/Plastic-Collimat...ItemQQimsxZ20090220?IMSfp=TL090220123001r1848
Jay

 

[danq]

Re: Key Chain Blu-ray... With FlexDrive!

re: negativity-
but what about just making a tiny board and mounting on the cells - that is, turning non-prot cells into protected?

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

DanQ: I am not yet sure i can even get the 10280 inside. I am however 100% sure i can't get an 10280 with a protection circuit taped to it's bottom inside..

That's why i'd like to do it under the driver.. Also, taping the circuit to a battery might not yield pretty results..  ;D


Otherwise, AW says that the circuit he sent me most likely has overcurrent protection set to 1A, but that he needs to check the specs....

If we didn't have an option of getting those PCBs, i'd be all for it. But i think it's easier to go with a factory made one, that's all. If however you can make one of those ICs interrupt the positive side, i'd be very interested...  


And even if you just want to make it for fun, go for it! I'm not against that. I am just looking for a simple solution, because i don't have the time to make my own protection circuits, that's all.. So if i can get them cheap from AW, it's much easier for me.

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

Hey Igor, I just turned my red key chain build up to 275mA's, and even at that current, I still get 200mW's using the Sony/Senkat 1239JL-54 diode along with the special AR coated lens that you showed me from flee-bay!

Nice...

Could you perhaps measure the current draw from a full battery, and later from an almost empty one?

Just use the highest current range on your DMM, and replace the tailcap with it.


BTW, the lenses increase the power some 10% or so. Didn't do very exact measurements tho. But i know they are better than both versions of the triple element glass. Only single element glass gets you a higher power. I get some 18% on the short FL glass lens.

 

[jayrob]

Re: Key Chain Blu-ray... With FlexDrive!

Ok Igor, using my DMM in place of the tail cap, I just took some measurements from both builds using a fresh charged battery, compared with a weak battery...

Current draw from battery: (corrected)

PHR blu-ray set at 117mA's - 175mA's steady with a fresh battery, 231mA's and climbing fast with a weak battery.

1239JL-54 red set at 275mA's - 228mA's steady with a fresh battery, 302mA's and climbing fast with a weak battery.

I guess with a weak battery, the FlexDrive tries to draw more current to make up for the drop in voltage needed huh? :-?

Anyway, maybe this information will help in your run time calculations for these settings...
Jay



P.S. It looks like the red at 275mA's, is going to have less battery run time, than the blu-ray at 117mA's. Even though the blu-ray diode needs more voltage.

 

[IgorT]

Re: Key Chain Blu-ray... With FlexDrive!

Ok Igor, using my DMM in place of the tail cap, I just took some measurements from both builds using a fresh charged battery, compared with a weak battery...

Current draw from battery:

PHR blu-ray set at 117mA's - 212mA's steady with a fresh battery, 250mA's and climbing fast with a weak battery.

Cool, thanks!

Looks like my calculations were a little low for the PHR. If i calculate for 117mA PHR on full battery i get an 183mA current draw (assuming 3.9V battery voltage under load and 5.2V Vf).

You measured 212mA, so either the battery sags more under load or the PHR's Vf is higher. Or a little of both. Or the FlexDrive efficiency is not actually 90%! I guess i should test it.

1239JL-54 red set at 275mA's - 315mA's steady with a fresh battery, 365mA's and climbing fast with a weak battery.

I guess with a weak battery, the FlexDrive tries to draw more current to make up for the drop in voltage needed huh? :-?

Exactly. That's what i was trying to explain before. A switching driver will have to draw a certain amount of POWER, not current. Since P = U x I, the lower U gets, the higher I has to be, for the power draw to stay the same.... That's the only way a switching driver can keep a constant output..

It's different than with linear drivers.

Anyway, maybe this information will help in your run time calculations for these settings...

Yea, it looks like i should measure the Flexy's efficiency at 3V out and 5V out, and use proper Vf data for calculations. Knowing the battery voltage under load would help as well. I can do these tests, when i get the tiny batteries.....

P.S. It looks like the red at 275mA's, is going to have less battery run time, than the blu-ray at 117mA's. Even though the blu-ray diode needs more voltage.

Yeah, that's because the PHR is at a lower power.

When did you raise the red to 275mA? At this current it will definitelly draw more than a PHR at 117mA.... My calculations on the previous page were for a red at 180mA. Did i misunderstand something there? Was i calculating for the wrong diode/laser?

What i said there was, that a 117mA PHR is a heavier load than a 180mA red... But you also said you made a 200mW red, and 180mA is not enough for that even with an AR coated acrylic, so i guess i was calculating for the wrong laser?  :-?


Anyway, basically, it's like this. All these diodes have a similar efficiency. In this case i'm talking about actual efficiency - electrical power IN vs. optical power OUT. Their efficiency is something like 17-20% after a plastic lens (plastic lens reduces efficiency of the system). Raw efficiency is obviously higher.

To make it more confusing, the losses in clear lenses are much higher with blu rays than reds, if you use the AR coated lens in a red and a clear in a blu the difference becomes even greater....

But if we ignore that, the fact that their efficiency is similar means this:
- If you have a red putting out 200mW and a blu putting out 200mW, their POWER consumption (voltage times current) will be almost the same.

Of course we all know that PHRs vary in efficiency quite a lot. Reds are more advanced and thus more consistent, but they do vary as well.


In the calculations, i had to make some numbers up:
- The Vf of your diodes (their voltage at that current)
- The voltage of a full battery under load.
- I assumed 90% as FlexDrive efficiency, altho it will be a bit more with Blu Rays and a bit less with reds (the higher the output voltage, the higher the efficiency)


If i had the first two values, i could make a much more accurate calculation for the current draw on a full battery. Like i said when doing those calcs, they were just approximations at best, with a lot of guesses involved. It was all very simplified. I didn't want to ask you to take the builds appart and measure voltage across the diodes..


But now that you have a 200mW red with an AR coated lens, it will again require a bit less power than a 200mW 6x Blu ray, due to the blu ray using a clear plastic lens. Did you make a 200mW 6x keychain blu? I'm getting confused with all these different diodes at different currents.

 

[jayrob]

Re: Key Chain Blu-ray... With FlexDrive!

Hmmm... I could have swore I read somewhere in your post before, that a red at 200mW should be about the same draw as my PHR at 117... But you must have said 'red at 200mW vs a 6X at 200mW.

Anyway, I already turned it up to 275mA's and I guess I'll leave it there for the time being. Starting at 291mA's battery current draw, that's still less that 2C of a 10280 battery and would theoretically last 1/2 hour or so... I believe.

I got my 10280 AW batteries, and they say 200mAh on them... so hopefully, they have more than 180mAh's. (stated on their site)

About the 6X... no, I have not built a 6X key chain laser yet. I think I will hold off until we test the run times with the 10280's.

I appreciate all or your calculations on this Igor!
Jay