battery drainage question

ive been using my tk15 on low for a little while now
when the batteries lose power is it common for the light to not cycle through all the modes

Every AA Fenix light I own behaves this way. First the turbo mode drops down to medium, then turbo and medium drop down to low and they all become the same low mode.

More prevalent with Alkalines and high current draw models, as they sag and can not really produce the current needed to run turbo at its brightest. My MC10 for example draws 3A at its highest setting. I have never bothered to take a current draw measurement with the alkaline, but its probably less than half of what the Eneloop delivers, and its only a little brighter on HI than MED. With an eneloop its a night and day difference.

I think I read somewhere that multi mode flashlights can be a risk when using recheargable batteries. If you use some of the lower modes you don't notice when the battery is too low in time, and the battery can be too much discharged. Therefore I prefer alkalines or lithiums when I don't use the highest mode for extended period. Am I right here, anyone who thought about this?

Swedpat said:

I think I read somewhere that multi mode flashlights can be a risk when using recheargable batteries. If you use some of the lower modes you don't notice when the battery is too low in time, and the battery can be too much discharged. Therefore I prefer alkalines or lithiums when I don't use the highest mode for extended period. Am I right here, anyone who thought about this?

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That makes sense to me. One of the drawbacks with any recharge capable chemistry is that it can not be over-discharged. I am kind of surprised Sanyo does not have protection circuits on eneloops. I have killed my share of them from accidental turn-ons and general carelessness.

If you are the type of user who just prefers to run it till' it dies then Lithium cells are a must, and single cell designs are the safest. I would never recommend alkalines of any brand due to their leak-prone nature.

iam useing lithium cr123 i have not gotten rechargeables for it yet

Swedpat said:

I think I read somewhere that multi mode flashlights can be a risk when using recheargable batteries. If you use some of the lower modes you don't notice when the battery is too low in time, and the battery can be too much discharged. Therefore I prefer alkalines or lithiums when I don't use the highest mode for extended period. Am I right here, anyone who thought about this?

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Depends on the light, and people have discharged eneloops to 0.0v and recharged them without damage. It is when there are multiple cells in lights that damage can occur via cell reversal. Some lights will run way down below 0.8-0.9v which is what most consider nimh cells fully depleted at. I figure that below 1.1v nimh cells have less than 5% capacity left and cannot sustain any but the lightest loads.

Lynx_Arc said:

Depends on the light, and people have discharged eneloops to 0.0v and recharged them without damage. It is when there are multiple cells in lights that damage can occur via cell reversal. Some lights will run way down below 0.8-0.9v which is what most consider nimh cells fully depleted at. I figure that below 1.1v nimh cells have less than 5% capacity left and cannot sustain any but the lightest loads.

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This is good to know, I will try and resurrect my "dead" cells. I thought it was a done deal, and I killed them.

thanks!!

kramer5150 said:

That makes sense to me. One of the drawbacks with any recharge capable chemistry is that it can not be over-discharged. I am kind of surprised Sanyo does not have protection circuits on eneloops. I have killed my share of them from accidental turn-ons and general carelessness.

If you are the type of user who just prefers to run it till' it dies then Lithium cells are a must, and single cell designs are the safest. I would never recommend alkalines of any brand due to their leak-prone nature.

Click to expand...

Yes, I like my CR123 lights because I use lithium primaries, and I don't need to worry of damaging the batteries. Some of my AA-lights I prefer alkalines because of the same reason. But I use to regularly control that the cells have not started to leak.

Lynx_Arc said:

Depends on the light, and people have discharged eneloops to 0.0v and recharged them without damage. It is when there are multiple cells in lights that damage can occur via cell reversal. Some lights will run way down below 0.8-0.9v which is what most consider nimh cells fully depleted at. I figure that below 1.1v nimh cells have less than 5% capacity left and cannot sustain any but the lightest loads.

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Ok, so single AA-lights will not be damaged by cell reversal? I have several lights tailstanding for making a cosy atmosphere at home as a complement to candle lights. Quark Mini AA, CR2 and CR123. Also Quark Preon AAA, Nitecore D10, 4Sevens regular 123 and Fenix LD10 I sometimes use for this purpose at the lowest mode. At this mode these lights run for days and nights and therefore I use alkalines to avoid overdischarge the batteries.

bouncer33441 said:

iam useing lithium cr123 i have not gotten rechargeables for it yet

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Bouncer, I believe the phenomenon you're experiencing is normal for a Fenix light and the result of Fenix's regulation. Others have mentioned it as well.

kramer5150 said:

This is good to know, I will try and resurrect my "dead" cells. I thought it was a done deal, and I killed them.

thanks!!

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I can't guarantee the cells are not damaged, but there was a thread someone took an eneloop and shorted it out with a clamp for over a day and then recharged it with no loss of capacity.

enlightened is the only that gave the answer to my question
than you

Swedpat said:

Yes, I like my CR123 lights because I use lithium primaries, and I don't need to worry of damaging the batteries. Some of my AA-lights I prefer alkalines because of the same reason. But I use to regularly control that the cells have not started to leak.




Ok, so single AA-lights will not be damaged by cell reversal? I have several lights tailstanding for making a cosy atmosphere at home as a complement to candle lights. Quark Mini AA, CR2 and CR123. Also Quark Preon AAA, Nitecore D10, 4Sevens regular 123 and Fenix LD10 I sometimes use for this purpose at the lowest mode. At this mode these lights run for days and nights and therefore I use alkalines to avoid overdischarge the batteries.

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Cell reversal is only applicable in multiple cell devices. It occurs when one battery (usually weaker than the rest) goes to zero while the device still has enough voltage from the remaining cells to power it. What happens is as the current goes through the cell that hits 0v it charges it backwards or reverse charges it. Alkalines are succeptible to cell reversal but it typically is a lot harder to reverse them due to their higher internal resistance.
Cell reversal can happen with lithium primaries also. I use generic nimh in devices that cell reversal is possible due to the chance of discharging them well below 1.1v. Lower capacity cells tend to be more durable when abused IMO.
Cell reversal in alkalines tends to greatly increase chances of leakage from my experience.

what is all this babble like i said it was a simple question that only one person answered

Lynx_Arc said:

Cell reversal is only applicable in multiple cell devices. It occurs when one battery (usually weaker than the rest) goes to zero while the device still has enough voltage from the remaining cells to power it. What happens is as the current goes through the cell that hits 0v it charges it backwards or reverse charges it. Alkalines are succeptible to cell reversal but it typically is a lot harder to reverse them due to their higher internal resistance.
Cell reversal can happen with lithium primaries also. I use generic nimh in devices that cell reversal is possible due to the chance of discharging them well below 1.1v. Lower capacity cells tend to be more durable when abused IMO.
Cell reversal in alkalines tends to greatly increase chances of leakage from my experience.

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Thank you for that great explanation!

bouncer33441 said:

what is all this babble like i said it was a simple question that only one person answered

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Apologize if I went this off-topic. I just thought my wondering is related to your question, and something which could be valuable to take in consider.

About the original question: According to my experience all multi mode lights start to lose the highest mode when the battery goes low. Then it will continue until only the lowest mode is available.

Regards, Patric

bouncer33441 said:

what is all this babble

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bouncer3341... you will need to learn some manners if you wish to continue here... :ironic:

kramer5150 said:

Every AA Fenix light I own behaves this way. First the turbo mode drops down to medium, then turbo and medium drop down to low and they all become the same low mode.

Click to expand...

PCS said:

Bouncer, I believe the phenomenon you're experiencing is normal for a Fenix light and the result of Fenix's regulation. Others have mentioned it as well.

Click to expand...

bouncer33441 said:

enlightened is the only that gave the answer to my question
than you

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bouncer33441 said:

what is all this babble like i said it was a simple question that only one person answered

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answer= yes.... or you could use the search function. :shakehead

Swedpat said:

Apologize if I went this off-topic. I just thought my wondering is related to your question, and something which could be valuable to take in consider.

About the original question: According to my experience all multi mode lights start to lose the highest mode when the battery goes low. Then it will continue until only the lowest mode is available.

Regards, Patric

Click to expand...