LED Flashlight/Lantern Bulb Selection

[SerenityNetworks]

I recently found and purchased an antique Ray-O-Vac flashlight/lantern. For a fun and useful project, I'd like to convert it to a very bright modern lantern using 18650 battery technology. But to start the project I need to determine a bulb to use. I am ignorant on the subject of solid-state bulbs. I need some help determining what to get. I hope I can find some help here. So, thank you in advance.


Here are my high-level desires.

• I would like the light to be as bright as reasonably achievable.
  • 1000 lumen would be great. More would be better. With the bulb housing such as it is, I'm not anticipating heat to be a problem (correct me if I am wrong).
  • Even with the batteries, the case has ample room for the needed circuit boards AND a collapsible plastic covering I can place over the light assembly to convert it from a flashlight to a lantern. For lantern use, the brighter the better. I'm hoping for general use that I can use it in place of my monster Coleman lantern.
• I would like the brightness to be variable. I don't care whether it is traditionally dim-able or has multiple brightness steps. (I'm thinking that with switches and circuit boards, stepped lighting might be the easiest to implement, but correct me if I'm wrong.)
• I would prefer to be able to use just one bulb, although I'm not totally opposed to using a multi-bulb assembly.

So, that is the project. I will appreciate all the direction you can provide. I do not mind doing my own homework, but with all the different options available I really do not know where to start.


Thanks,
Andrew

 

[lightfooted]

Quite the project. The key would be finding a reflector to replace the existing one so that you can always return it to original state without any problem. At least that is what I would do. Perhaps a prebuilt emitter array for some already inexpensive Ali Baba light or something like that. Paired up with a driver that can control output with a separate switch...I know they exist outside of proprietary modules. Planning to use the original type of cells or install a Li-Ion pack/cell?

 

[SerenityNetworks]

1. The key would be finding a reflector to replace the existing one so that you can always return it to original state without any problem. Perhaps a prebuilt emitter array...

I had thought I'd build from scratch, if feasible. But that's looking less do-able. So yes, it may be easier to fit in an existing assembly.

• For example, the assembly on the old Atomic Beam flashlight my wife got me a few years ago would fit (although I'd have to settle on a fixed beam focus).
• I would greatly prefer something quality and bright over cheap.

2. Paired up with a driver that can control output with a separate switch...

What the heck is a driver?

• I'm only familiar with AC drivers that rectify the AC and then regulate the DC current and voltage. Since we're already using DC, does a flashlight driver only regulate the current and voltage?
• If so, can the driver be separated from the light portion of the assembly and will I need multiple drivers? That is, how do I provide different levels of brightness?
• Note: One part of the project is to have an output from the battery pack going to a circuit board that will allow me to charge a phone or other USB 5VDC products. Is this circuit the same as a driver?

3. Planning to use the original type of cells or install a Li-Ion pack/cell?

18650 Li-Ion pack for sure. I'll get much greater energy density and still have room in the housing for circuit boards and such.

It seems using an LED is a bit more complex than just a battery and a bulb. But I'd still like to work through the project.

Thanks,
Andrew

 

[DIWdiver]

Hi SerenityNetworks, and welcome to the forum!

A flashlight LED driver regulates the current. At the specified current, the LED determines the voltage. That's if everything is working properly.

That said, any particular driver and battery selection will have a range of output voltages that they can provide (for example, a 3V battery and a buck driver can't drive a 6V LED, but a 9V battery and the same buck driver could).

Some drivers are fixed output current, and some are adjustable. Brightness can also be adjusted by turning the current on and off very rapidly (fast enough that the eye cannot detect it). This is called Pulse Width Modulation, or PWM.

The circuitry for a USB charging port may have many similarities to an LED driver (or not), but they have different purposes and thus different designs. The voltage regulator for the port could look very much like the LED driver circuit, but would have at least slight differences. If you wanted to create one of the more intelligent ports that can output various voltages, the design would be much more complex.

Agreed, using an LED is more complex than an incandescent bulb, but it doesn't have to be hard, and the efficiency is WAY better.

By the way, a single switch can do on/off and dimming, even smooth dimming. I built a driver for my under-cabinet lights in the kitchen. It has a touch sensor to control it. You can turn on or off one or two sets of lights, smoothly dim up and down, just by touch and release or touch and hold. If you put one of the open-source controller boards (arduino, etc) in the light, your imagination is the limit. Some of those boards aren't much bigger than a postage stamp and only cost a few dollars.

 

[SerenityNetworks]

Thanks DIWdiver. I'm learning.

Right now my attention has been on the XP-L2 and XP-L/HI (~1100 lumen), the XP-L/HI (at 1883), the XHP50/50.2 (at 2546), and the XHP70/70.2 (at a whopping 4,292 lumen). They all seem to have the same form factor with star mounts from 12mm to 20mm, so my questions relate to exactly what parts to order and will I have an issue with heat dissipation on the higher output emitters. Of course, if I could find a drop-in pill that I could fit into the existing housing, that would be great.

 

[Dave_H]

Not knowing these specific LEDs, rough estimate is half the dc power supplied to the LED will be
dissipated as heat.

Not sure if this would work, but there are some cheap compact 3AAA 5W LED flashlights with high
output (but not 1000 lumens) which might be adapted by removing the head/LED assembly. Have
not tried this myself. These lights run fine on one 18650, in fact usually fits in place of the round 3AAA
holder in the body. Controller for these lights normally sequence high-mid-low-strobe-SOS.


Dave

 

[Dave_H]

. By the way, a single switch can do on/off and dimming, even smooth dimming. I built a driver for my under-cabinet lights in the kitchen. It has a touch sensor to control it. You can turn on or off one or two sets of lights, smoothly dim up and down, just by touch and release or touch and hold. If you put one of the open-source controller boards (arduino, etc) in the light, your imagination is the limit. Some of those boards aren't much bigger than a postage stamp and only cost a few dollars.

Several very low-cost desk LED desk lamps use the SGL8022W control chip which does touch control
and step or continuous up/down PWM dimming but does not provide switching-type constant-current
conversion/regulation (only linear). Might be part of the overall solution, otherwise just an interesting device.
Not sure where to obtain them other than from the lamps themselves.

Dave

 

[SerenityNetworks]

Thanks Dave.

This is just a quick reply. I'm going to be preoccupied for several days. I'll post back (hopefully) next week sometime with some ideas based on what I've been learning.

 

[DIWdiver]

Dave, that SGL8022W looks like a pretty neat chip. Based on their suggested schematics, it looks like the output must be PWM, which should be easily adapted to other types of drivers. The 'driver' in their circuits is just a resistor and bipolar transistor.

LCSC Electronics in Shenzhen, China stocks the part, and ships globally. They have a nice website in English too. Digipart.com shows a load of other distributors with stock, but LCSC looks like the best one of only two that cater to low volume buyers.

AliExpress will deliver a lot of 100 for under $20, that's not bad either.

 

[Dave_H]

DIW: yes, interesting chip with good datasheet which is important for doing any work with it. PWM dimming
was confirmed with a scope on a cheap desk lamp, on which I modified the mode (described in another
thread). Chip seems intended for direct-drive linear LED control where highest efficiency isn't the prime
concern. Not sure how/if chip itself would fit into the OP's scheme.

So, I'll throw out another idea to the OP:

You could acquire a suitable low-cost LED flashlight with built-in rechargeable Li-ion plus the USB charger
circuit, and possibly "transplant" components into your vintage lantern. I have seen a couple
locally for under $20 recently which are in the 3-5W LED range. Of course the optics need to work as well
as electronics; and no sense getting one with exotic expensive machined body (and exotic name and price
to match), much of which will largely discarded.

I have an old metal Ray-O-Vac flashlight but extent of my LED ambition was to replace the 3v incan. bulb
with a drop-in LED replacement...flange-base ~1/2W with about the same light output, but different tint
and beam pattern, and much longer battery life.

Dave