In need of direction, with a small project

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
I have a small project that I've wanted to build for a while but I'm not quite sure where exactly to start. It's probably already been done several times and I'm just wanting to package it differently. I want a battery power light with a simple delay-ON via a clickable switch (pressing again turns it off). I'd like it to run off a CR123 in some way since I have a lot of them. Something in the 200-300 lumens would be great. Beyond that, I'm at a loss on where to begin. I have a couple books I've been studying but they are a bit advanced for what I'm doing. Any help would be appreciated.
 

WBahn

Joined Mar 31, 2012
29,844
I think that LEDs typically produce about 100 lumens per watt. Could be wrong. Could be different for the LEDs you are using.

CS123 batteries are 3 V with typically 1500 mAh capacity.

So, using round numbers, to get your 300 lumens, you need 3 W of power, which is 1 A from a 3 V battery, so you can expect one cell to last somewhere between one and two hours.
 

BobTPH

Joined Jun 5, 2013
8,659
Sorry, I misread that, but the comment still stands.

Max continuous discharge rating is 60 mA, which will not get you 10 lumens, let alone 100.
 

BobTPH

Joined Jun 5, 2013
8,659
I think that LEDs typically produce about 100 lumens per watt. Could be wrong. Could be different for the LEDs you are using.

CS123 batteries are 3 V with typically 1500 mAh capacity.

So, using round numbers, to get your 300 lumens, you need 3 W of power, which is 1 A from a 3 V battery, so you can expect one cell to last somewhere between one and two hours.
That capacity will not hold up at 1A discharge rate, in fact, I doubt it can produce 1A even momentarily.
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
That capacity will not hold up at 1A discharge rate, in fact, I doubt it can produce 1A even momentarily.
Your comments leave me wondering how all the flashlights I have work then. I have two 500 lumen models and one that is 1,000. All of them run on 2 CR123 batteries and have stated run times of 1.5 to 2 hours.

To clarify, I would just like to use this battery in any configuration required, not just a single battery.
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
I think that LEDs typically produce about 100 lumens per watt. Could be wrong. Could be different for the LEDs you are using.

CS123 batteries are 3 V with typically 1500 mAh capacity.

So, using round numbers, to get your 300 lumens, you need 3 W of power, which is 1 A from a 3 V battery, so you can expect one cell to last somewhere between one and two hours.
I'm open to using any configuration required for the output. As mentioned in another reply, I know 2 of these batteries can produce 500+ lumens. I'm just not smart enough to know how they work internally (series or parallel).

I was also toying with the idea of multiple LED's/panels to produce a flood effect. I'm guessing this will require a lot more power/batteries.
 

WBahn

Joined Mar 31, 2012
29,844
That capacity will not hold up at 1A discharge rate, in fact, I doubt it can produce 1A even momentarily.
I don't know what the good range of currents is and, unfortunately, this information is often hard to find, even on manufacturer's datasheets (which is annoying, because it would seem to a pretty important and valuable piece of information).

I did some digging around and found this chart from Duracell:

1687317123494.png

This would indicate that 1 A is doable, but the terminal voltage drops to about 2.5 V almost immediately and it will die at about the one hour point.

This datasheet did provide standard and maximum continuous discharge current information, which I usually don't see. In this case it is 20 mA and 60 mA, respectively. Given the curve above (in the same datasheet), I don't know what their basis is for determining 60 mA as the max continuous current. Perhaps that is related to the current that results in the capacity falling below the rated capacity?
 

strantor

Joined Oct 3, 2010
6,778
That capacity will not hold up at 1A discharge rate, in fact, I doubt it can produce 1A even momentarily.
Sorry, I misread that, but the comment still stands.

Max continuous discharge rating is 60 mA, which will not get you 10 lumens, let alone 100.
Something is off with these figures, I'm not sure what, but I can verify that a flashlight running on a single CR123 can absolutely put out 300 lumens and it can do it for more than an hour. I have this streamlight on my rifle. It runs on a single CR123 and you can believe the specs on that page; those are not Chinese Amazon specs. That thing provides enough light to make positive ID on rabbits on a cloudy night at 150yds.
 

WBahn

Joined Mar 31, 2012
29,844
Your comments leave me wondering how all the flashlights I have work then. I have two 500 lumen models and one that is 1,000. All of them run on 2 CR123 batteries and have stated run times of 1.5 to 2 hours.

To clarify, I would just like to use this battery in any configuration required, not just a single battery.
If the two batteries are in series, you have more voltage than you need and they might be using a step-down converter to drop the voltage and increase the amperage, perhaps cutting the battery current to something on the order of half of the LED current. Depends on the circuitry in the light.
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
I'm not even sure I'm smart enough to understand the info you all are giving me. I just don't know what I don't know.

My only real parameters are the lumen output and the batteries. It would nice if this could be packaged up into something similar in size to a decent flashlight (8"-9" long, 2" dia). Beyond that, I have no clue on how to design the circuitry.
 

WBahn

Joined Mar 31, 2012
29,844
When you say that you want it to have a "delay on", could you describe exactly the behavior you are trying to achieve?
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
When you say that you want it to have a "delay on", could you describe exactly the behavior you are trying to achieve?
I'd like to press a button, have the lights delay coming on for 3 to 5 seconds (some fixed time), then stay on until either the button is pressed again to turn off or the battery dies.
 

jiggermole

Joined Jul 29, 2016
161
As far as the delay circuitry I would start looking into analog toggle switches. As a direction to start. That may lead you to one that you can tinker with and get your desired delay. Before that you may want to look at how you're going to drive the led, which may tell you how you want to do the on delay stuff. LED driver chips are pretty common so a lot of options there.
https://www.digikey.com/en/products/filter/power-management-pmic/led-drivers/745
I picked an arbitrary xlamp from cree. 290 lumens 700mA draw. That little battery wouldn't last long but it might work okay if using a driver chip. Using that arbitrary led selection that narrowed the led driver selection down. The LED, and the narrowed list of drivers. I don't know how deep you want the help to be. Hand holding or send off to learn. My first real pcb project was a similar project to this. Made a rechargeable led work light for my dad.
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
As far as the delay circuitry I would start looking into analog toggle switches. As a direction to start. That may lead you to one that you can tinker with and get your desired delay. Before that you may want to look at how you're going to drive the led, which may tell you how you want to do the on delay stuff. LED driver chips are pretty common so a lot of options there.
https://www.digikey.com/en/products/filter/power-management-pmic/led-drivers/745
I picked an arbitrary xlamp from cree. 290 lumens 700mA draw. That little battery wouldn't last long but it might work okay if using a driver chip. Using that arbitrary led selection that narrowed the led driver selection down. The LED, and the narrowed list of drivers. I don't know how deep you want the help to be. Hand holding or send off to learn. My first real pcb project was a similar project to this. Made a rechargeable led work light for my dad.
I'd take all the help I can get. I started with an electrical circuit textbook and doubled back to a for Dummies book just so I could read the first.

I know exactly what I want the finished product to do; I just don't understand the inner workings well enough to create it. I keep imagining a "sub-assembly" that contains anything to do with the circuitry (LED's, wiring or PCB's, batteries, etc.) and an external assembly that contains it all. I can make the outside once I have the inside done correctly.
 

jiggermole

Joined Jul 29, 2016
161
I started with eagleCAD and brute force digging through datasheets and beating my own skull learning. I should have started with reference designs to fully UNDERSTAND what I was getting from the datasheets. https://www.digikey.com/reference-designs/en/lighting/led-drivers-dc-in/270 Digikey, Texas Instruments, and Analog all have reference design sections. I'm sure Newark or whatever you use to get parts would have a reference design section too.
Once you get the components figured out to do what you want them to do, you still don't necessarily have to design a pcb yet. You can get parts you can breadboard, or carrier pcbs made to solder fine pitch components to so they will breadboard and mock it all up before paying for a pcb to be made. Thats a recomendation I think anyone here at AAC can get behind.
Now that eagle was bought by autodesk its a bit different, but autodesk has a bunch of tutorials for learning how to operate the software.
Another option you can do is look on amazon/ali-express/alibaba for a cheapo already functioning pcb. I've done that with bluetooth speakers and such. Order the pcb that does almost what I want and figure out how it does it. It already functions and, if not schematics, than you can poke and prod with the meter to figure out whats going on.
This is too big for your application, but this one is an example of what I'm talking about.
 

jiggermole

Joined Jul 29, 2016
161
Aliexpress is a better option for the pre-made solutions. Here is one from there. The manufacturer has a couple of options. Its a 3W driver which is over the 2W needed for that LED that I linked to. If nothing else, one more place for ideas.
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
As far as the delay circuitry I would start looking into analog toggle switches. As a direction to start. That may lead you to one that you can tinker with and get your desired delay. Before that you may want to look at how you're going to drive the led, which may tell you how you want to do the on delay stuff. LED driver chips are pretty common so a lot of options there.
https://www.digikey.com/en/products/filter/power-management-pmic/led-drivers/745
I picked an arbitrary xlamp from cree. 290 lumens 700mA draw. That little battery wouldn't last long but it might work okay if using a driver chip. Using that arbitrary led selection that narrowed the led driver selection down. The LED, and the narrowed list of drivers. I don't know how deep you want the help to be. Hand holding or send off to learn. My first real pcb project was a similar project to this. Made a rechargeable led work light for my dad.
Could you explain how the driver works or refer me to something with more info on them?
 

Thread Starter

Alln3w2m3

Joined Jun 20, 2023
57
I started with eagleCAD and brute force digging through datasheets and beating my own skull learning. I should have started with reference designs to fully UNDERSTAND what I was getting from the datasheets. https://www.digikey.com/reference-designs/en/lighting/led-drivers-dc-in/270 Digikey, Texas Instruments, and Analog all have reference design sections. I'm sure Newark or whatever you use to get parts would have a reference design section too.
Once you get the components figured out to do what you want them to do, you still don't necessarily have to design a pcb yet. You can get parts you can breadboard, or carrier pcbs made to solder fine pitch components to so they will breadboard and mock it all up before paying for a pcb to be made. Thats a recomendation I think anyone here at AAC can get behind.
Now that eagle was bought by autodesk its a bit different, but autodesk has a bunch of tutorials for learning how to operate the software.
Another option you can do is look on amazon/ali-express/alibaba for a cheapo already functioning pcb. I've done that with bluetooth speakers and such. Order the pcb that does almost what I want and figure out how it does it. It already functions and, if not schematics, than you can poke and prod with the meter to figure out whats going on.
This is too big for your application, but this one is an example of what I'm talking about.
The second picture in that reference guide link is very similar to how I thought this item would turn out. I had imagined boards with the necessary LED's and connections linked to a battery able to power it.

As far as parts, I haven't ever bought any outside of a local shop that is now closed. I only got a few intending to breadboard the idea, but this was ages ago.

Are there any online solutions to designing or toying with layouts before purchasing parts to test on a breadboard?
 
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