- Joined
- Oct 24, 2008
- Messages
- 1,057
- Points
- 48
There has been some concern that the new 445nm diode in a CR123 host cannot be pushed to extreme currents because CR123 cells cant handle the wattage. Well that may be true for Li-ion CR123 cells. At least until they drop below ~75% charge. Their loaded voltage drops too low for the driver to run. However, that is not necessarily the case with these LiMN CR123 cells. Unfortunately I don't have my 445nm build completed yet, but I can still test the batteries.
The diodes seem to vary, at least the posted measurements vary. Anyways they can consume anywhere between 3.5-6 watts of power from the driver depending on what current they're driven at. The Boostdrive and Flexdrive have conversion efficiencies between 80-95%. So the batteries must supply the driver anywhere from .7-1.5 more watts that the what the diode is consuming.
So a moderately powered diode around 800mW or so might consume about 4-4.5 watts from the battery. Setting the diode to 1200mW or more can really stress the Li-ion batteries and pull up to 6 watts from it. Again the math can vary alot but in general it's a pretty good guesstimation. So if you want alot of power out of your diode and are using a Li-ion cell you can't expect a very long lifetime from a single charge. Not that it exhausts the amp hours quickly, but because unless the cell is fully charged the battery will struggle to keep the voltage up above 3v or so and the driver will shut down. Bring down the current and the voltage climbs back up. So the capacity doesn't matter in that respect. I've seen this all the time LED emitter torches.
Anyways, these LiMN cells are much better. They're able to handle higher current discharge and keep their voltage up pretty well. It's a difference chemistry than Li-ion and it allows for 8C discharges at 550mAh.
I bought two of them from Lighthound for 7 bucks each.
AW IMR16340 550 mAh IMR CR123 size LiMN Rechargeable Lithium Battery
Here are some specs you'll need to know.
Min safe voltage: 2.50v
Max charge voltage: 4.20v
Capacity: 550mAh (milli amp hours)
Max charge rate: 1.5A
These cells should not be left discharged for long periods or they can become damaged. That's common for most Lithium based batteries. But they will not explode or catch fire if they are over-discharged like Lipo cells will. They should be stored at about 3.6v or higher. Compared to other cheaper Li-ion based CR123 cells 550mAh isn't that great. Or at least it's not an improvement. Alot of the Ultrafire and Trustfire cells are often underspec are are also usually around the 550mAh range.
Anyways, I bought them for my 445nm build. So I wont mind the small capacity if they can supply the needed current. In short, they deliver.
I tested them under heavy current draw when they were at about 70% charged. That is to get an "average performance" of the cell throughout the discharge. Had I tested the peak voltage I wouldn't have gotten a good general representation of the cells performance. The unloaded voltages of the cells are 3.9v and 3.92v, practically the same.
At 3.5 ohms the current draw and loaded voltages are;
1.07A 3.62v
1.07A 3.63v
At 2.6 ohms the current draw and loaded voltages are;
1.37A 3.53v
1.37A 3.54v
At 2.1 ohms the current draw and loaded voltages are;
1.66A 3.43v
1.66A 3.43v
So even at almost 6 watts the battery kept the voltage at a suitable level for the driver. If the driver is drawing 1.66A then the diode is really burning for a handheld laser. Again it'll vary, but that's probably about 1200mW out of the diode. I let the battery go at 1.66A for a few minutes and I noticed that the loaded voltage will drop about .15v per minute. So after about 5-7 minutes the driver may have shut down due to not enough voltage. But remember the battery was at about 70%. All in all you'll probably get about 15-20 minutes of runtime from a full charge if you're really pushing the diode, >1000mW. That's actually better than I expected. If you set your diode to a more conservative 6-800mW then you'll probably get almost a half an hour or runtime. That to me is good enough. I can't imagine a situation in which I would need my laser for more than that amount of time in one sitting, and plus I have two cells. So these are good candidates for a CR123 445nm build. You won't be restricted, as much, to running the diode at the power you want.
I give them a 9.5/10
-Tony
The diodes seem to vary, at least the posted measurements vary. Anyways they can consume anywhere between 3.5-6 watts of power from the driver depending on what current they're driven at. The Boostdrive and Flexdrive have conversion efficiencies between 80-95%. So the batteries must supply the driver anywhere from .7-1.5 more watts that the what the diode is consuming.
So a moderately powered diode around 800mW or so might consume about 4-4.5 watts from the battery. Setting the diode to 1200mW or more can really stress the Li-ion batteries and pull up to 6 watts from it. Again the math can vary alot but in general it's a pretty good guesstimation. So if you want alot of power out of your diode and are using a Li-ion cell you can't expect a very long lifetime from a single charge. Not that it exhausts the amp hours quickly, but because unless the cell is fully charged the battery will struggle to keep the voltage up above 3v or so and the driver will shut down. Bring down the current and the voltage climbs back up. So the capacity doesn't matter in that respect. I've seen this all the time LED emitter torches.
Anyways, these LiMN cells are much better. They're able to handle higher current discharge and keep their voltage up pretty well. It's a difference chemistry than Li-ion and it allows for 8C discharges at 550mAh.
I bought two of them from Lighthound for 7 bucks each.
AW IMR16340 550 mAh IMR CR123 size LiMN Rechargeable Lithium Battery
Here are some specs you'll need to know.
Min safe voltage: 2.50v
Max charge voltage: 4.20v
Capacity: 550mAh (milli amp hours)
Max charge rate: 1.5A
These cells should not be left discharged for long periods or they can become damaged. That's common for most Lithium based batteries. But they will not explode or catch fire if they are over-discharged like Lipo cells will. They should be stored at about 3.6v or higher. Compared to other cheaper Li-ion based CR123 cells 550mAh isn't that great. Or at least it's not an improvement. Alot of the Ultrafire and Trustfire cells are often underspec are are also usually around the 550mAh range.
Anyways, I bought them for my 445nm build. So I wont mind the small capacity if they can supply the needed current. In short, they deliver.
I tested them under heavy current draw when they were at about 70% charged. That is to get an "average performance" of the cell throughout the discharge. Had I tested the peak voltage I wouldn't have gotten a good general representation of the cells performance. The unloaded voltages of the cells are 3.9v and 3.92v, practically the same.
At 3.5 ohms the current draw and loaded voltages are;
1.07A 3.62v
1.07A 3.63v
At 2.6 ohms the current draw and loaded voltages are;
1.37A 3.53v
1.37A 3.54v
At 2.1 ohms the current draw and loaded voltages are;
1.66A 3.43v
1.66A 3.43v
So even at almost 6 watts the battery kept the voltage at a suitable level for the driver. If the driver is drawing 1.66A then the diode is really burning for a handheld laser. Again it'll vary, but that's probably about 1200mW out of the diode. I let the battery go at 1.66A for a few minutes and I noticed that the loaded voltage will drop about .15v per minute. So after about 5-7 minutes the driver may have shut down due to not enough voltage. But remember the battery was at about 70%. All in all you'll probably get about 15-20 minutes of runtime from a full charge if you're really pushing the diode, >1000mW. That's actually better than I expected. If you set your diode to a more conservative 6-800mW then you'll probably get almost a half an hour or runtime. That to me is good enough. I can't imagine a situation in which I would need my laser for more than that amount of time in one sitting, and plus I have two cells. So these are good candidates for a CR123 445nm build. You won't be restricted, as much, to running the diode at the power you want.
I give them a 9.5/10
-Tony
