How does the EO-9L work on both Li-Ion and normal 3v lithiums?

[fire-stick]

~snip~
EO-9L Extreme High Output
9V, 450 Lumens Extreme High Output Reflector Module
(For 3 x CR123A Batteries and 2 x 3.7V Rechargeable D36 Flashlights)
~snip~

If this is a 9v lamp how could it work on 2 x 3.7V batteries?

Wouldn't that be 7.4v?

Wouldn't it be dimmer on 2 x 3.7 v batteries?

thanks

fire-stick

 

[GreyShark]

I'm no expert but the trick is that 3x 3v primaries don't deliver 9v into a load, it's actually a lot less. Also 2x 3.7v rechargeables don't deliver 7.4v, they actually come off the charger at 4.2 volts and they hold the voltage into the load a lot better than 3v primaries. So the seemingly 7.4v setup is really 8.4v and holds higher than the supposed 9v setup. Plus the bulb itself is usually overrated. This makes understanding electricity hard, because nobody is talking sense. :mecry:

 

[cernobila]

I'm no expert but the trick is that 3x 3v primaries don't deliver 9v into a load, it's actually a lot less. Also 2x 3.7v rechargeables don't deliver 7.4v, they actually come off the charger at 4.2 volts and they hold the voltage into the load a lot better than 3v primaries. So the seemingly 7.4v setup is really 8.4v and holds higher than the supposed 9v setup. Plus the bulb itself is usually overrated. This makes understanding electricity hard, because nobody is talking sense. :mecry:

Yeah, something like that.......fact is I only use this lamp on the 2x 18650 cells and it is excellent in my M90. I don't use primary cells, too expensive here in AU.

 

[csshih]

wait.. that happens when you use IMRs, then?

 

[cernobila]

wait.. that happens when you use IMRs, then?

The discussion above is talking about the original established Li-Ion cells (18650/168 size) such as the WE, AW and Pila. No idea how the EO-9L would go on 2x IMR18650 cells........anyone else like to comment?

 

[GreyShark]

With IMR's the volts should be the same, the capacity will be a lot less and the safe discharge rate will be a lot higher. If the device doesn't draw more amps than the non-IMR cells can provide I don't see how/why there would be any difference with IMR's other than a shorter run time.

Kind of like when you rummage through a parts bin looking for a power supply for some device you can use anything that's the same voltage as long as it can also provide the needed amps or higher.

 

[Patriot]

What the others said. The primaries voltage sags to around 2.5V each or 7.5V total. 2 x 17500's start off at 8.4V total and sag very little so they're brighter.

 

[nzgunnie]

9v is only the nominal voltage of the lamp, just like '3v' and '3.7v' are only the nominal voltage of the cells.

Read this post:

http://candlepowerforums.com/vb/showthread.php?t=161536

It needs to be compulsory to read this post before entering the incandescent forum! Kind of like those software licence windows, but so you can't just click through it...:twothumbs

 

[cernobila]

It needs to be compulsory to read this post before entering the incandescent forum! Kind of like those software licence windows, but so you can't just click through it...:twothumbs

You are right there.....this would save a lot of time and effort to explain the basics, we could then concentrate on the more tricky questions......

 

[Patriot]

That thread is a true CPF trophy! :twothumbs

 

[mdocod]

It's pretty common for primary cells to have voltage ratings closer to their open circuit behavior, and rechargeable cells to have voltage ratings that more closely represent their average voltage delivered into a load. I'm not sure why this difference exists in the industry, but it does. Same is true for "1.5V" alkaline vs 1.2V NIMH/NICD, in truth, the 1.2V cell actually averages a higher average operating voltage through a discharge into most loads we are likely to see in demanding consumer devices than the "1.5V" alkaline.

When it comes to tactical lamps assemblies for lithium powered flashlights, you will generally have 2 voltage ratings.
1. The consumer voltage rating.
2. The actual voltage rating.
In this case, it's:
1. 9V
2. ~7.2-7.6V (depending on the bulb and other factors).

If you go to LFs website and lookup the bulb specifications chart, you can find out what the actual target voltage rating of the bulb is.

 

[325addict]

exactly! there are 3 charts with the D36 lamp assemblies, the lowest one shows the actual design-voltages of the bulbs. A "9V" bulb seems to be more like 7,2V or 7,4V or something like that.

I can tell you one thing for sure: when using an M90, you can safely use "normal" Li-ions. AWs will have a 2200mAh capacity then. So it is safe to draw 4.4 Amps!
The EO-9L will draw 2.4 Amps so this will give you nearly an hour of runtime.

It's better however, to switch off the light after 45 minutes or so, to preserve the batteries.

The standard bulb of the M90 only draws 1.3 Amps, so the runtime with the EO-9L will, whatever batteries you are using, only be 1.3/2.4 = 54% of what you once had.... For convenience, say, the runtime is cut to half the time you once had!


Timmo.