DIY SolarForce project and help understanding drop-in's.

[DasFriek]

I just received my 1st SF this week which was an L2r and i ordered it due to my mass amount of AA rechargeable. But after seeing the quality they put into their lights id like to build one to my specs and accessories.

Here is my main problem i have a hard time wrapping my head around, Drop-ins.
Here is a the voltage options they carry at SF for P60's.
0.8-4.2V
3-6V
4.2-8.4v
4v to 18v

Im pretty sure im gonna go with a L2i body so i can use as many power options as possible.

Do the drivers in these drop-ins need to be matched as close to the maximum voltage ill be running? That way the driver sends the max amount of available voltage to the emitter?

If thats the case if i got the 4v to 18v drop in and i only used 6v would it be a pretty dim light as the driver would under-drive the emitter?
I know overdriving is bad no matter what.

0.8-4.2V with 1x18650 3.7v would equal almost max output of the emitter?
4.2-8.4v with 3x AAA 4.5v would be pretty much a dim light even on high?

Also, They show options to run 320Lms XPG R5 emitters at 18v but only 320 lumens.
Then they list a XM-L T6 Cree 820 Lumens that max out at 6v.
Is the R5 brighter than 320 lumens at 18v?
And does the XM-L have to be over driven to hit 820 lumens, say 12v?


Is my thinking on this close in how P60's work with different battery combinations?

 

[^Gurthang]

Das,

Drivers have TWO specs to consider; the input voltage range and the drive current delivered to the emitter. the 0.8 - 4.2 Vf driver as you surmised is for AA / CR123 or single Li-Ion cells. The 3-6 Vf is for 1-2 CR123 primary cells or single Li-ion, 4.2-8.4 is a "buck" driver for multiple CR123 or Li-Ion cells, the 4-18 Vf driver is for 4+ CR123 primaries or 2-4 Li-Ions. Other than the 0.8 - 4.2 range, the other Vf ranges were chosen by SureFire when they developed their various tactical / weapon lights using CR123 primary cells and incandescent lamps. The newer LED drop-ins are configured to match those SF configurations.

 

[DasFriek]

Ok, So the goal is to get the drop-in and try and match its MAX voltage to the MAX voltage ill be using? I think thats what your saying and what i figured.
But can you tell me why they have 18v drop-ins that are rated at 320 lumen's and then 4v drop-ins rated for 800+ lumen's?
Are they understating what the 320 lumen drop-in will do at 18v? And im sure the 4v drop-in will never get close too 800+ lumen's.
But is saying that, Are they saying you need to overdrive the 4v drop-in? Mostly its seen on single mode XM-L T6 emitters.

I know its all about theoretical numbers and many times completely false numbers, Both in lumen's and voltages.

One extra question which is important i get answered also and ill ask here so i don't have to start a new thread or have to PM 45/70 as i bug him enough.
But how dangerous do things get when you venture over 2 Li-ion cells?
I see many configurations for 4x-6x cr123 and 2x-4x 18650 bodies and id almost be afraid to hold a light like that while on high past 30 minutes as id be scared to know what the cells are doing since you cant get a real time display of each cells voltage and amps. Id be waiting for it to grenade on me.

For now im sticking with 2x 18650 until i learn more, Plus the light is gonna be killer in stock form anyhow.
SKU 55109 at DX
BeamTech T6 Cree XM-LT6 5-Mode 850-Lumen White LED Flashlight with Strap - Black (2 x 18650)
But this light has a 18v max and it would be easy to run 4x cr123's and im rather sure i can get SolarForce extensions and run 6x cr123 or 4x 18650's.

I mainly ask this as that light should be here in the next few days, and i want to see and use it before i build my light from SolarForce as i don't want to build two lights that are so similar. For the price its a monster to start with and just a couple of extensions would make it twice the light, But i may need a new XL-M drop in that allows for higher amps over 2.2amps.

 

[45/70]

Hi Das. Since you drug me over here form the batteries and electronics forum:sigh:......:crackup:

I'm not any sort of electronics expert by any means, but I can tell you this. Most of the drop ins that you mention that can accommodate high voltages, such as 18V, do so to allow enough cells in the "battery" to extend the runtime, not to necessarily increase output. Because of this, a 4 Volt driver could easily output more lumens than an 18 volt driver. The driver itself pretty much determines the current that the LED will be driven at, not the voltage.

Also generally, a driver with a range of 4-18 Volts will actually run more efficiently at 4 Volts, than 18. As ^Gurthang mentioned, these units are "buck" circuits, that is they basically lower the voltage (actually this is a byproduct of regulating the current, since LED's are current driven, not voltage driven, as an incandescent filament is) needed to drive the LED. So, the more closely the actual voltage provided by the "battery", the less the circuit has to do and is thus more efficient at the lower end of the voltage range.

With a 0.8-4.2V driver, for example, this is usually, a "boost" circuit. That is, the circuit is required to boost the voltage up to the required voltage (again actually a byproduct of regulating the current) to drive the LED, which is typically 3-3.5 Volts. So with a boost circuit, the reverse is true, compared to a buck circuit and the circuit is most efficient at the higher voltage end. It is also worthy to note that "buck" circuits are almost always more effcient than "boost" circuits. It is easier to reduce voltage than to increase it. Works similar to your wallet when you hang around CPF.:)

Also it is only "boost" circuits that can be "overdriven" with a regulated circuit driver. This occurs when the cell, or cells voltage minus the voltage drop from the driver itself, is higher then the Vf of the LED. There is also such a thing as a "buck/boost" driver circuit that prevents this from happening, but you don't see a whole lot of those around.

As for your battery question, you bring up some good points. I think we covered some of this in another thread, but as long as you match the cells well, use protected cells, and don't do anything stupid, like letting the battery tube of the light get hot enough to cook an egg, or something, you should be OK. Just the same, you are correct, the more cells you have in series, the higher the risk of an "event".

Hope this helps. There are many others here with a much higher IQ in electronics than I, that can probably better help you with your driver questions. Hopefully someone will chime in. Also, read, read, and read some more.

Good luck with your LEGO project!:)

Dave

 

[^Gurthang]

Das,

One point to keep in mind is the emitter used in a drop-in and heatsinking limits. P60 drop-ins are based on a SureFire form factor and are NOT ideal for high output emitters. Most Cree XR & XP emitters can handle 1.2 - 1.5 A current and w/ good body contact run on high w/o overheating. When you move into the HIGH output emitters; Cree MC-E, XM-L, SSC P7, or SST-50 these emitters can handle 3 -5 A current to reach max output. A P-60 format is inadequate to take that sort of heat for more than a few minutes. High Vf rated drop-ins can operate at lower current ratings as the Vf rises.

The other point to consider is the batteries. NiMH cells and deliver 2+ A of current, the common 18650 Li-ion can deliver 2+A current as well, IMR Li-ions can deliver over 10A current as can Li Po. A single cell light will try to deliver what ever current the driver is calling for, which can lead to over draining a cell [bad for Li-ions]. Multi cell lights draw less current since the voltage is higher, meaning you can run longer or deliver more current for a BIG emitter.

You might find a look at some of the Lumens Factory incandescent drop-ins instructional. Look on the LightHound site.

http://www.lighthound.com/Lumens-Factory_c_119.html

Hope some of this helps answer your questions.

 

[DasFriek]

(Applause) Thanks for putting into words i can understand, Most likely it would take me a few more weeks to learn all that on my own with searches and digging.
I wasn't finding much info that i needed to move my project forward. Sorry to take you from your normal environment tho.
^Gurthang Had the info there, But i couldn't quite wrap my head around it yet, After reading your post i now understand what he was saying.

I have a ready to go Lego light coming from DX which can almost everything a person would hope to do with a XL-M T6 drop-in.
But without the driver knowledge i was fudged to say the least.

I can go two ways with this build and one way is almost already done and that is the C8 CREE XM-LT6 series of copies that run 1x 18650.
Or to build it threw SolarForce and build it like i want, But it will be much more expensive. But it also will look many times better, But yet be the same light as the C8.
SF has a 3v-6v drop-in which may give me 1x 18650 options with 2x cr123's but id like to search for its drivers specs amp wise at different voltages.
But they have the .8v-4.2v drop-in which ill need more specs before making a decision.
Basically i need to apply the info you guys gave me here with the specs the drop-ins have.

I have these two lights coming from DX and should be here this week as they have been on US soil a few days now.
SKU 55109
SKU 44713
Both should give me the chance to learn and have fun with mixing and matching cells and cell chemistry.
The AA version is ripe for a XL-M drop-in even tho it will cost as much as the light does.
And the first one should allow me to see how 18v drop-ins react to different voltages as i am able to take tail amp readings.

But i was concerned about how many Li-ion cells in series would be safe if done right or if it was even recommended to do so or not.
Ill definitely use matched Surefire primary cr123's as they are very consistant in voltage as i hand tested each one in the box of 12 and all were a perfect 3.23v on the nose. The Titanium cells from BJ were all over the place at 3.22v- 3.27v but i was able to match them in pairs so that isnt to bad, But i cant use them in anything past a two cell configuration.
Plus i have four TF black/red 18650's on hand and 2 in the mail and out of the four i have on hand, Two of them like to droop too much too 4.13v while the other two droop only too 4.16v. You get what you pay for and when dealing in touchy setups im gonna wait until i have the AW 2900mAH or Panasonic 3100nAH cells before i try anything over 2 cells.
I think SolarForce's 18650 extension tubes should fit the SKU 55109 light and allow more range upto 18v if that isnt overkill once i get it here and look at it.

 

[DasFriek]

Das,

One point to keep in mind is the emitter used in a drop-in and heatsinking limits. P60 drop-ins are based on a SureFire form factor and are NOT ideal for high output emitters. Most Cree XR & XP emitters can handle 1.2 - 1.5 A current and w/ good body contact run on high w/o overheating. When you move into the HIGH output emitters; Cree MC-E, XM-L, SSC P7, or SST-50 these emitters can handle 3 -5 A current to reach max output. A P-60 format is inadequate to take that sort of heat for more than a few minutes. High Vf rated drop-ins can operate at lower current ratings as the Vf rises.

The other point to consider is the batteries. NiMH cells and deliver 2+ A of current, the common 18650 Li-ion can deliver 2+A current as well, IMR Li-ions can deliver over 10A current as can Li Po. A single cell light will try to deliver what ever current the driver is calling for, which can lead to over draining a cell [bad for Li-ions]. Multi cell lights draw less current since the voltage is higher, meaning you can run longer or deliver more current for a BIG emitter.

You might find a look at some of the Lumens Factory incandescent drop-ins instructional. Look on the LightHound site.

http://www.lighthound.com/Lumens-Factory_c_119.html

Hope some of this helps answer your questions.

I just missed your post before i wrote my reply above, Ill reread it and reply in a bit and appreciate the insight as its extra info i didnt know also.
Thanks for the help also!

 

[DasFriek]

The C8 CREE XM-LT6 I mention is one example of an emitter being driven to its max thermal abilities. Ive read alot on that light and the help it needs thermally.
I have a computer building background and have done alot of modding in my time and most related to over volting and unorthodox cooling measures.

Im also not experienced with high amp single cell run times and the ability of the cell to be over drained. But i would like to have a drop-in thats a 3 mode when possible so i can switch to a medium setting if i have no spare cells and i feel the circuitry would have a better chance of protecting the cell at lower drain rates.
At least from what ive read that trick works most times.
Im really interested in how drivers work with given voltages over the rated range they have. It sounds like single cell lights drivers are the easiest to predict and the 18v drivers can be a mixed bag of dung or gold depending on what your looking for.

About cooling P60's, Does a light with a larger head help over some of the smaller ones they usually have? I know its still a P60, But if its done right can the larger head make for lower temps? Also when looking at higher voltage XL-M emitters is it best to look for lights that don't use P60 drop-ins and use a proprietary larger cooling setup in the head?

Thanks for the LH link, I knew about them but didn't really look at their info or drop-ins.

Id like to make a statement so you guys don't think im in over my head or a dreamer and possibly a nut case. If i was to do everything ive talked about next week id say i was in over my head.
But ill slowly experiment my way along the lines that interest me, Just being informed ahead of time helps me pick a road to head down, Not meaning im gonna do everything ive talked about instead.
Luckily lights as a hobby is rather affordable once you get past the chargers and multiples of cells so i can pretty much do anything DIY that interests me.
Many times i wont duplicate a route that will lead me to a finished product thats a copy of a light i already have.
Who knows, If the info is out there, i may even try my hand at driver modding as i have an EE background. Add that with my thermal dissipation experience i may end up way off the map somewhere.
So until you see me say i bought something, Like the two DX lights. Then usually im thinking out loud and info gathering and learning for my next step.

I hope that makes sense, I know at times my head doesn't translate thought into writings too well.

 

[2100]

I know for the Solarforce P4 warm white drop in, its 4-18V or something. But on 1 cell 4.2V or 2-cell 8.4V, there is no intensity difference, as captured on the camera + the histogram (ie it is accurate). But the Solarforce Masterpiece Pro-1, there is a difference bt 1-cell and 2-cell. My 2 other Q5/Q4 drop-ins purchased from DX also displayed no differences for 1 or 2-cell, they accept voltages up to 12V and 18V.

So it depends.

 

[45/70]

Das, just a quickie, as it's been a long weekend (not all bad, but long).

About cooling P60's, Does a light with a larger head help over some of the smaller ones they usually have?

Yes, the bigger the head and the bigger the light body, to some extent, the better the heatsinking. One thing you have to remember is that when over driving an LED, it's a bit different than over driving a CPU. An LED is tiny compared to the smallest computer processor chip. The contact area that the actual LED has to dissipate the heat generated within, compared to a processor chip is way smaller. Just the same, tight fitting components, heat sinking compound etc. will help, but not nearly as much as with a computer processor, in other words there is only so much you can do when the heat is generated from an object the size of a pinhead. All the heat sinking, water cooling, or whatever method you use, isn't really going to make a whole lot of difference when the LED junction heats up when over driven, it just won't take the heat away fast enough, at some point, it's still going to get really hot.

Dave

 

[2100]

Yes, the bigger the head and the bigger the light body, to some extent, the better the heatsinking. One thing you have to remember is that when over driving an LED, it's a bit different than over driving a CPU. An LED is tiny compared to the smallest computer processor chip. The contact area that the actual LED has to dissipate the heat generated within, compared to a processor chip is way smaller. Just the same, tight fitting components, heat sinking compound etc. will help, but not nearly as much as with a computer processor, in other words there is only so much you can do when the heat is generated from an object the size of a pinhead. All the heat sinking, water cooling, or whatever method you use, isn't really going to make a whole lot of difference when the LED junction heats up when over driven, it just won't take the heat away fast enough, at some point, it's still going to get really hot.

Yeah...and for CPUs you can use exotics like Peltier cooling, vapour phase change, and liquid nitrogen/dry ice. Different physical setup.

That's why the next step would be multiple emitter setups, but still limited to the lumens dept and not lux, unless you do not mind a big head. :D

 

[DasFriek]

2100- What you say is the hardest things about drop-ins ive run across. No maker lists how the drop-in will react at certain voltages or cell count, The best way ive found info so far is hearing personal experiences from people like you. Also no one leaves detailed reviews on drop-ins on retail websites to inform buyers and far as i know there is no forum or drop-in fact section. Most likely because they change parts and take some off the market faster than people can buy and test them.
Im 50/50 split on buying drop-ins and attempting to mod them.
First reason is most drop-ins cost as much as a whole light does with the same drop-in, And secondly if i screw up a part replacements are a 1 month wait from China.
I may be OCD about my hobbies, But i lack that kind of patience. I barely can stand the 3-4 week wait it takes to get lights, Waiting on parts would drive me insane.
I can only stand the wait for lights due to the extremely low prices, Had them be close to USA prices i may not even be that interested in lights as a hobby as much.

45/70- Ive read alot about the difficulties of cooling emitters due to how they are attached to the PCB's and some solder joints and how the star is set into the block. Im very aware of thermal compounds abilities and lack there of also. If its not applied in thin layers with pressure or not affixed with a thermal epoxy to keep the part held tight against the heat-sink its almost a waste. Thick amounts of compound is worse than nothing many times as it can actually insulate more than transfer.
And the worst part is your need to work under the emitter and cant clamp from above which is a big downfall, And on such a tiny item its a delicate job.
Even worse is i haven't even looked deep enough in at a P60 to see what could be improved and where, Ive only eliminated the air gap on my Solar Force L2r which didnt really need it being a 2xAA setup. But i did it to learn mostly.

BTW i did water cooling by building my own setups from scratch and also phase change cooling, Along with air cooling certain parts most times don't have issues unless your pushing the whole system hard like i was. Many mosfets had hand made and cut heatsinks applied by me in power regulation section of the mother board.
Talk about a frustrating and expensive hobby. $1k-$3k per system just in parts and you always have to have a second setup that is reliable so you can research and get help when your project has a bug and wont boot and allow internet use.

 

[^Gurthang]

Das,

If you do some searching on CPF you'll find LOTS of threads regarding P60 drop-ins. Recent discussions about heat transfer and wrapping the P60, high output P60s, high CRI P60s / emitters. And some regarding ideas on how to improve the P60 form factor. BTW, have you read the "sticky" threads at the head of the LED light forum? TONS of very useful info / FAQs etc.