Runtime of Primaries Vs. Rechargeables

[chillinn]

Regulated lights generally will step down and may eventually drop out of regulation into direct drive when the cell/s can no longer provide enough current. Most manufacturers of lights using primaries will give the runtime until the cell is depleted and the light shuts off, not when the light drops out of regulation. You have the mAh ratings on the sides of cells, and if they are accurate, that is what you get, so 1600mAh of primary is the same as 1600mAh of secondary, no more and no less, just like a ton of feathers weighs the same as as a ton of lead, and a motorcycle going 60mph is no faster than a station wagon going the same speed.

 

[nitebrite]

Amen chillnn. That is the answer I was looking for. We can be done with this now. There is only one notable difference and it does not have to do with mah. It is amperage. Some lights cannot use 123A's by design. Since a 123A has maximum 3.5 Amps constant drain. Many good 18650 and larger LI-Ion cells feature 15+ Amp constant drain. Some double that. The lights that run on 123A's I take it do not pull many amps. However most lights will run on 123A's. It is only the "extreme" lights that will not. All of Surefires lights always have run on 123A's. Many of them today get plenty bright. I like the analogy, a ton of feathers weighs the same as a ton of bricks. It is exactly the same. If perhaps not cost effective. I do not like that someone says a certain battery is better performance than one of the same mah. They are exactly the same. Assuming one is not simply junk. We can conclude this conversation now if everyone wishes. Thank you all

 

[archimedes]

.... Some lights cannot use 123A's by design. Since a 123A has maximum 3.5 Amps constant drain....

This is incorrect. I point this out (again) primarily as a safety issue, and have mentioned this exact point in another of your threads, just a few days ago.

As others have pointed out, most quality CR123A batteries are safety rated at ~ 1500 mA continuous draw....

 

[archimedes]

.... You have the mAh ratings on the sides of cells, and if they are accurate, that is what you get, so 1600mAh of primary is the same as 1600mAh of secondary, no more and no less, just like a ton of feathers weighs the same as as a ton of lead, and a motorcycle going 60mph is no faster than a station wagon going the same speed.

Generally speaking, you may want to compare Wh, not mAh, as voltage differs between chemistries.

 

[nitebrite]

okay, archimedes I know that you know your stuff and fully trust you. So a 123A is only 1500mA continuous drain? I am not speaking of their mah but their drain amperage. I figure that you realize that. They say 3.5A on the package. That is downright dangerous! If they are only 1500mA how do they go in lights with an XPL? An XPL can be driven to 3000ma. This is dangerous! Of all people a company starting with Sure is doing this. You remember how how hot their Luxeon III got. Not sure what the draw was. The Dominator does not draw more than 1500ma? No wonder mine tested at 1900 lumens in the Sphere. Pretty low bar. I guess the EDCL2-T must be highly efficient as well. When it comes to the Chinese lights however, I suppose anything goes. Unless stacking 123A's in series increases the ampacity overall?

So If running 123a's in series does not increase their available "power". I gather 1x Samsung 40T is much stronger than 2x 123A in series? With regulation the driver does not care of the increased voltage, only the mah I gather. Thank you

 

[WalkIntoTheLight]

Generally speaking, you may want to compare Wh, not mAh, as voltage differs between chemistries.

Yes, and voltage curves differ between brands and models, even with the same chemistry. And available voltage also differs depending on load. So, you can really only know what the watt hours are if you measure it with the exact battery and load you're going to use.

Generally, regulated lights care about watt hours, not mAh. The efficiency of their buck/boost driver might vary a bit depending on the voltage of the battery, but it's minor if the driver is properly designed. Some "regulated" lights that use linear drivers (7135 chips) will just burn off excess voltage as heat. Most regulated budget lights do it that way.

 

[nitebrite]

Interesting. I just found out that a fully charged 40T runs lights much brighter than cheaper 21700's 18650's and 2x 123a's. I would think it would not matter. Only run time.

 

[archimedes]

okay, archimedes I know that you know your stuff and fully trust you....

I am not too familiar with the SF Dominator. Is that the one than can run on 12 primaries, in a 4S3P carrier ?

If so, there is your answer :thinking:

 

[archimedes]

I realize that some on CPF are critical of the Battery University "articles" but many of them do provide a relatively readable (if oversimplified) primer on these topics.

https://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

 

[nitebrite]

You are correct about the Dominator. The 123A pack simply has more mah than their rechargeable stick. I was just speaking about a single Samsung 40T 21700. That thing packs a huge punch. It makes lights brighter. I would not think this would be possible with regulated lights. If I use another 21700 or 18650 or 2x 123a the lights are not nearly as bright. Speaking of course of lights that take 21700's. I have confirmed this with a lux meter,

 

[chillinn]

Generally speaking, you may want to compare Wh, not mAh, as voltage differs between chemistries.

This. Yes. ><