EvilLithiumMan
Enlightened
I'm combining numerous topics about the SMJLED PR2 in this post. Anyone who wishes to add anything is invited to do so.
The Good
The SMJLED PR2 has improved, (in brightness, quality and battery life) just about every 2 cell host I have tried. Even if you are not prone to any kind of modding, you should still have one or two handy to replace a burned out PR2 incandesant. And they are great for kid's lights too. If junior falls asleep with the light on, chances are it will still be burning brightly when you find it.
Great results with a Garrity Tuff Light and a MagLite. Good results with the Rayovac Industrial and the Eveready Contractor. As with any reflector, larger and deeper yield better results. The Rayovac reflector is somewhat shallow and it's too bad there isn't a glass lens availble. I'm sure the thick plastic one is holding back some light. Ironically, the facetted pattern of the Rayovac provided the smoothest and roundest hotspot.
Although I can't prove it, because I don't have both lights, I still think the Eveready Contractor is identical to the Walmart 84 cent special. I took a file and trimmed down the ribs:
This allows for not only CR123 cells, but 18650 Li-Ion as well:
Which is my segue to ...
The Bad
So what happens when you power the SMJLED from 4.15 volts, a Li-Ion cell hot from the charger? You are rewarded with an incredibly brilliant beam. Which draws 525ma. And lasts about 90 seconds
(Like it was surprise) But I just had to know. I haven't done any extensive current measurements yet. But in general, here is what I've found:
3.2 volts, typical new cells, alkaline or carbon zinc - 240 to 260ma
3.0 volts - 180ma
2.7 volts - 120ma
2.5 volts - 80ma
2.2 volts - 32ma (Way too dim here. I feel 2.5 volts is about where I would replace / recharge cells)
I haven't been able to locate a manufacturer's data sheet, but it seems that 80 to 100ma is used as the nominal current for these devices.
At these low (lower than a normal incandesant) loads, I was wondering if I couldn't hooble together a light that would last a full week, 168 hours, at nominal brightness. (I'm just talking about what, 10 to 15 lumens? Something a MagLite 2D would provide) I looked up the capacity of an Energizer 6 volt lantern battery. It is given as 26000mah. Wow, a 130ma load should theoretically last 200 hours. Knowing that a 6 volt lantern battery consists of four 'F' cells, couldn't I take two 'F' cells, which are a '3/2 D size', and put them in a MagLite 3D? I went to Walmart and got their lowest cost lantern battery, a Rayovac $2.97 cabon zinc, and tore into it like a chimpanzee into a cupcake. Which is the segue for ...
The Ugly
The plastic case looks nice on the outside. But on the inside:
Nothing sophisticated here. Uninsulated cans, with interconnect wires attached with a huge blob of solder And look at the huge ding one cell had:
But they all measured fine on a voltmeter. And what about the length? Well, the camera's perspective isn't quite perfect, but yes indeed, 2 x 3/2 does equal 3:
The carbon zinc cells have been powering the SMJLED PR2 for 36 hours now. Voltage at 2.6 and current at 104ma. I'm not sure that translates into Energizer cells going for a full week. Perhaps only 3 to 4 days.
What's next on my SMJLED agenda? I think I'll pop one into my Rayovac 6v lantern, making sure I have only three volts powering it. It has a very large reflector and should do well. And I think I'll see how long (or if) the SMJLED PR2 can handle 300ma. Might be fun to get a 300ma Badboy converter and build a regulated light.
Well, to parapharse, if not down right hijack, another member's tag line:
"Sorry for the long post. I didn't have the time to do a short one."
The Good
The SMJLED PR2 has improved, (in brightness, quality and battery life) just about every 2 cell host I have tried. Even if you are not prone to any kind of modding, you should still have one or two handy to replace a burned out PR2 incandesant. And they are great for kid's lights too. If junior falls asleep with the light on, chances are it will still be burning brightly when you find it.
Great results with a Garrity Tuff Light and a MagLite. Good results with the Rayovac Industrial and the Eveready Contractor. As with any reflector, larger and deeper yield better results. The Rayovac reflector is somewhat shallow and it's too bad there isn't a glass lens availble. I'm sure the thick plastic one is holding back some light. Ironically, the facetted pattern of the Rayovac provided the smoothest and roundest hotspot.
Although I can't prove it, because I don't have both lights, I still think the Eveready Contractor is identical to the Walmart 84 cent special. I took a file and trimmed down the ribs:
This allows for not only CR123 cells, but 18650 Li-Ion as well:
Which is my segue to ...
The Bad
So what happens when you power the SMJLED from 4.15 volts, a Li-Ion cell hot from the charger? You are rewarded with an incredibly brilliant beam. Which draws 525ma. And lasts about 90 seconds
(Like it was surprise) But I just had to know. I haven't done any extensive current measurements yet. But in general, here is what I've found:3.2 volts, typical new cells, alkaline or carbon zinc - 240 to 260ma
3.0 volts - 180ma
2.7 volts - 120ma
2.5 volts - 80ma
2.2 volts - 32ma (Way too dim here. I feel 2.5 volts is about where I would replace / recharge cells)
I haven't been able to locate a manufacturer's data sheet, but it seems that 80 to 100ma is used as the nominal current for these devices.
At these low (lower than a normal incandesant) loads, I was wondering if I couldn't hooble together a light that would last a full week, 168 hours, at nominal brightness. (I'm just talking about what, 10 to 15 lumens? Something a MagLite 2D would provide) I looked up the capacity of an Energizer 6 volt lantern battery. It is given as 26000mah. Wow, a 130ma load should theoretically last 200 hours. Knowing that a 6 volt lantern battery consists of four 'F' cells, couldn't I take two 'F' cells, which are a '3/2 D size', and put them in a MagLite 3D? I went to Walmart and got their lowest cost lantern battery, a Rayovac $2.97 cabon zinc, and tore into it like a chimpanzee into a cupcake. Which is the segue for ...
The Ugly
The plastic case looks nice on the outside. But on the inside:
Nothing sophisticated here. Uninsulated cans, with interconnect wires attached with a huge blob of solder And look at the huge ding one cell had:
But they all measured fine on a voltmeter. And what about the length? Well, the camera's perspective isn't quite perfect, but yes indeed, 2 x 3/2 does equal 3:
The carbon zinc cells have been powering the SMJLED PR2 for 36 hours now. Voltage at 2.6 and current at 104ma. I'm not sure that translates into Energizer cells going for a full week. Perhaps only 3 to 4 days.
What's next on my SMJLED agenda? I think I'll pop one into my Rayovac 6v lantern, making sure I have only three volts powering it. It has a very large reflector and should do well. And I think I'll see how long (or if) the SMJLED PR2 can handle 300ma. Might be fun to get a 300ma Badboy converter and build a regulated light.
Well, to parapharse, if not down right hijack, another member's tag line:
"Sorry for the long post. I didn't have the time to do a short one."
