Will running 2x+ lithium battery lights on Low modes tend to balance the cells?

[eh4]

I am thinking of the firefly and 2 lumen mode of the Armytek Barricuda Pro in particular, with a firefly burn time advertised at 200 days there is already good reason to simply leave the light on in between uses, if there is any benefit to the batteries then even more so.

Alternately, will running a high output multiple lithium cell light on turbo tend to drain a battery in front or in back position more than the other (s)?
Or is it only a matter of capacity and internal resistance in any cell of the same chemistry?
-and so, if mismatched cells were used, the more depleted battery would be the one with less capacity or greater internal resistance, completely irrespective of their order in series...

Ok, another way of looking at it, say there is a battery mismatch and the lower capacity cell had been depleted down to 3.5v while the healthier battery is at 3.8v. Now coming out of turbo to low, say 2 lumen output, will the higher voltage battery give up its energy more easily than the compromised battery?

 

[eh4]

Maybe I should ask on a vaping forum.

 

[ChrisGarrett]

Maybe I should ask on a vaping forum.

I started out replying to your post earlier today and then checked myself.

The stronger battery/cell can start reverse charging the weaker cell and that's no good.

I don't think that running cells in series balances them, per se, because if you have a weak cell, it's going to perform differently than a good cell. Running them down together doesn't make the weaker cell better, or balanced with the better cell, the way I see it.

Hobby chargers do balance multiple cells in packs, so we know that, but I don't think a hobby charger works the same was as a flashlight on firefly mode, when it comes to keeping things in equilibrium, but I could be wrong?

This is why we want cells from the same batch code, made at the same time and in the same physical condition when we run multi cell lights, especially those in series.

I think that with parallel configurations, it doesn't matter all that much.

If you own an analyzing charger, you can do some tests and match cells to one another, from a group of cells.

Chris

 

[eh4]

Thanks for the input Chris, appreciated.
Yeah I'm just wondering if, since there is a danger to the 2× battery configuration with high discharge, if there is also possibly a remedial upside to 2x with long, slow discharge.

 

[ChrisGarrett]

Thanks for the input Chris, appreciated.
Yeah I'm just wondering if, since there is a danger to the 2× battery configuration with high discharge, if there is also possibly a remedial upside to 2x with long, slow discharge.

I read here a lot and I'm no electronics whiz, so others will perhaps chime in, but 'always' start multi cell series lights with the cells of the same model and in the same condition, be it a 2, 4, 8 cell light, or more.

And for series lights, protected cells are the way to go if they fit a particular light.

I run naked Samsung 25Rs in my 4x18650 modified Supfire M6, but they're arranged in parallel, so it's less of a concern.

I do see one cell that reads a couple of hundredths of a volt lower, but I don't really use it all that much and a 4P configuration isn't as dicey.

Chris

 

[eh4]

I'm still not sure if it's a deep question or a dumb one but I'm eager to get to the bottom of it.

 

[write2dgray]

My extensive testing of batteries over the years in various similar configurations tells me no, it will not.

 

[eh4]

I'm gonna test the idea with two alkaline AAA, then if that shows anything remotely interesting, maybe try it again outside with two CR123.
I figure that most people here are conscientious about matched cells and good charging, and the few who may not be wouldn't notice if their mismatched cells benefited from long duration low modes...
I'm not entertaining the idea that the lower functioning cell would be improved, but that the higher one might give up more of its juice, temporarily reducing the mismatch, and reducing the possibility of a catastrophic failure when high mode was accessed again.
I never intend to use anything but well matched, protected cells, if I ever even do get a multiple cell lithium powered light, it's just a worst case thought experiment.
I'm off to run down a AAA and put it in series with a fresh one, hook them to a 5 mm led for a while.

 

[write2dgray]

The deal is: equal current flows through each battery, just at different voltages. So, you are removing the same mAh from each cell over a given period of time.

 

[eh4]

Got It.
Thank you write2dgray, that makes good sense.

I think that my confusion here comes from an over reliance on the analogy of water head for voltage and volume of flow for amperage:

If the analogy is perfect, then the cell with more head/elevation drop/preasure(voltage) should give up more of its flow volume(amperage) than the cell with less head/elevation fall/presure (voltage).

 

[bobrip]

Got It.
Thank you write2dgray, that makes good sense.

I think that my confusion here comes from an over reliance on the analogy of water head for voltage and volume of flow for amperage:

If the analogy is perfect, then the cell with more head/elevation drop/preasure(voltage) should give up more of its flow volume(amperage) than the cell with less head/elevation fall/presure (voltage).

I think that would be true if they were in parallel. If in series the current is identical with both cells. The only path is through both cells when in series.

 

[FRITZHID]

I think that would be true if they were in parallel. If in series the current is identical with both cells. The only path is through both cells when in series.

Parallel cells self balance eachother regardless of light being on OR any other electronic device being connected.

 

[eh4]

I think that would be true if they were in parallel. If in series the current is identical with both cells. The only path is through both cells when in series.

Parallel cells self balance eachother regardless of light being on OR any other electronic device being connected.

Thanks Bob, and Fritz for clarifying. I think I got it.