Anyone pushing a Cree XPG R5 on 4 cr123 protected rechargeables?
- Thread starter Buckfever
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AnAppleSnail
Flashlight Enthusiast
I'm guessing that you mean the driver in the dropin. More rechargeables in series can lead to other problems. It depends on the driver how the LED is run.
I guess that's what I'm getting at. Why would they have a driver in a drop in to handle 18V if rechargeables in series are still unstable? If you're going to go with 4 regular cr123a wouldn't you just go with 2 18650 rechargeables? And you wouldn't need it to handle 18V. Are there cr123 rechargeables presently that are considered stable to run 4 in series? I'm seeing some apps where 3 are run in series.
I have a lot of catching up to do. In what application would it need to handle 18V?
Last edited:
AnAppleSnail
Flashlight Enthusiast
If you do enough things wrong, li-ions in series can go excitingly wrong. The same is true of fireworks, dogs, and pencils. If you have mis-matched, unprotected cells AND one dies before the others, AND it reverse-charges and heats up, AND enters a runaway reaction, you will have some extent of problem (Failed light to small toxic explosion). This usually happens when a user inadvertently mixes a fresh and old cell (Whether li-ion or lithium). Given the number of loose cells in the world, this is a rather rare occurrence. Don't go home and throw all you Lithium cells in a fireproof safe; they work pretty well.
Why higher-voltage drivers? Well, an LED really only takes about 3.5v per LED in series. But incandescent torches tend to be more powerful at higher voltage, and some LED drop-ins are meant to be direct replacements. And hey, "I can take all the volts" is a good feature to claim. Sometimes it gives better battery life. In theory, you can convert 100 mA at 18v into 600 mA at 3v, but the drivers aren't 100% efficient.
In these cases, you could set up a buck driver light with quality, fresh CR123s, and put it in a box for ten years and still have quite a bit of life left in it. However, not all drivers are created equal. Some drivers actually just throw away the extra voltage as heat!
Why higher-voltage drivers? Well, an LED really only takes about 3.5v per LED in series. But incandescent torches tend to be more powerful at higher voltage, and some LED drop-ins are meant to be direct replacements. And hey, "I can take all the volts" is a good feature to claim. Sometimes it gives better battery life. In theory, you can convert 100 mA at 18v into 600 mA at 3v, but the drivers aren't 100% efficient.
In these cases, you could set up a buck driver light with quality, fresh CR123s, and put it in a box for ten years and still have quite a bit of life left in it. However, not all drivers are created equal. Some drivers actually just throw away the extra voltage as heat!
