Proper batteries for modded lights

blerkoid

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Aug 31, 2013
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Hello CPF,


I am wondering which batteries should be used for modded lights?
The lights heat up faster and drain more - so I am not sure if my eagtac 3400 mAh are the best for the job.


I have been told that they will work, but is there better out there?
I prefer to use protected cells as there is less stress. Not sure if that is a factor.


Thanks in advance for any information and teaching coming my way.
Take care!
 

RetroTechie

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Which lights (brand / model / version)?
Modified in what way? Especially if it concerns electronics. Emitter swaps with the same emitter type just a different tint, dedome etc, wouldn't matter much since it wouldn't affect current draw much.

There is no 1 best answer, as different lights will load their batteries in different ways (and changing in different ways during discharge). Some batteries will perform better in one situation, other batteries will perform better in another situation. Of course discharge current is the #1 factor here. But possibly not the only one.

In general, batteries based on Panasonic 3400 mAh cells (which I think includes that Eagtac 3400 you mention) are considered among the best out there. Protection does nothing to enhance performance - just safety. Which for most uses should be the #1 concern, tbh. :)
 

blerkoid

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Thank you very much!

i will be using the TK61vn and the TK75vn. As far as I understand these lights will be de-domed and amped up a bit for more throw and otf lumens.

I guess I just need to order more of the same.
is there a better recommendation of batteries for these lights?

Thanks!
 
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Overclocker

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first determine your current draw, then goto: lygte-info.dk/review/batteries2012/Common18650comparator.php

that should answer all your questions

as for NCR18650B (like your eagtac 3400) it's definitely not the best for the vast majority of single-cell lights out there. this cell's discharge curve isn't flat and a lot of the energy is only available at the very low voltages. it's actually rated down to 2.5v. but's it's great on multi-cell lights

on a single-cell flashlight with buck driver the LG D1 charged at 4.35v is actually far superior to the NCR18650B
 

RetroTechie

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on a single-cell flashlight with buck driver the LG D1 charged at 4.35v is actually far superior to the NCR18650B
+1

A lot depends on the LED driver, and up till what voltage batteries can be discharged. A buck driver will pump some % of its input power to the LED, so in that case a battery's energy contents (up to that low voltage) is what matters. Higher average battery voltage = more energy. As the battery nears empty, current draw goes up.

For a linear driver OTOH (like those popular AMC7135 based drivers), its roughly: LED current = battery current, where excess voltage is wasted. Again, up to whatever low voltage battery & driver can handle. In this case, the mAh figure at a given current draw (up to low voltage) is what matters. Over the course of discharge, current draw is mostly flat.

And in a simple battery -> resistor -> LED light, it's mostly the same as with a linear driver. But in this case, as the battery nears empty, current draw goes down too. One will understand that batteries can behave very different depending on these use cases.
 

blerkoid

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My head hurts... I think I need to start a bit more basic on the batteries because I don't understand a lot of that lol. It all sounds very smart and specific, though. I will begin my studying soon - then this will mean a lot more to me.
 
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