Using UnProtected Cells in a High Drain Flashlight

OttaMattaPia

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Good afternoon,
Being relatively new to the higher end flashlight hobby, I've read many opinions on the use of unprotected cells in high drain LED flashlight applications.
The particular flashlight is a Convoy L6.

Since I've never had a flashlight with this much power demand, I thought it would be a good idea to ask in general terms how much risk I run of having a battery mishap using unprotected vs protected cells with this flashlight.

The Convoy L6 does have built in low battery protection that I believe kicks in at 6 volts. But should that be trusted to prevent a battery mishap?

That said, I wouldn't necessarily consider myself a pending Darwin Award recipient and I do have respect for the potential for overheating the cells by over-discharging them and I'm aware of the potential and basically what the danger is. I would tend to use this light in short bursts of 1 minute or less. Once I detect a rise in temperature or a decrease in light output I would always turn the light off and recharge the batteries.

Is there more I could do? Is it foolish to attempt to use this particular light with UnProtected cells?

The only protected cells I've been able to find that will fit in the Convoy L6 are the KeepPower 26650's because they hav to be under 70mm's in length.

Thanks for your replies.
 
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Timothybil

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The problem you are going to run into is how high of a current are we talking about. Most of the protected cells I have seen have an approximate 4A-5A cutoff. I do remember seeing one cell with a 10A cutoff for the protection circuit, but couldn't tell you where. If your light is going to pull more than that, you might not have a choice about protected vs unprotected. It is good that your light has a low voltage cutoff. Also, if your light is going to pull that kind of amperage you will be looking at the IMR cell chemistry, and most IMR cells are unprotected.
 

OttaMattaPia

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The problem you are going to run into is how high of a current are we talking about. Most of the protected cells I have seen have an approximate 4A-5A cutoff. I do remember seeing one cell with a 10A cutoff for the protection circuit, but couldn't tell you where. If your light is going to pull more than that, you might not have a choice about protected vs unprotected. It is good that your light has a low voltage cutoff. Also, if your light is going to pull that kind of amperage you will be looking at the IMR cell chemistry, and most IMR cells are unprotected.


Thanks.
The one I see recommended for the Convoy L6 is the KeepPower protected 26650, 5200mAh cell. It has a cut out at 9.4A

Those are about $35.00 for two but since I have several 3500mAh and 4200mAh 26650's (unprotected) I'm just wondering how much risk I'm taking using them since they are unprotected cells?
 

CelticCross74

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OP Convoy specifically states to use protected high amp cells. There are 2 different length Keeppower 5200mah 26650's. One is over 71mm long and the other roughly 69mm long. The shorter of the two is specifically meant for the L6. Illumn.com gets the shorter ones but they sell out almost instantly. Gearbest is the only other source of the shorter ones that I know of. I started out with the longer ones in my L6 and I could barely screw the tailcap back on and ended up denting inwards the positive ends of both cells. Also the longer cells made the L6 glitchy. Go for the short Keeppowers as they are specifically meant for the light. Took awhile to get mine from Illumn but I got them and now the light just flat out cranks and is not glitchy.
 

snowlover91

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Thanks.
The one I see recommended for the Convoy L6 is the KeepPower protected 26650, 5200mAh cell. It has a cut out at 9.4A

Those are about $35.00 for two but since I have several 3500mAh and 4200mAh 26650's (unprotected) I'm just wondering how much risk I'm taking using them since they are unprotected cells?

Since acquiring a few Zebralights that can only use unprotected cells I've come to prefer them versus protected cells. The main thing you'll need to be careful of is over-discharge of the cells. A good charger and you'll shouldn't have to worry about charging them too much, I always check mine just to be sure though whether charging protected or unprotected cells. Usually most lights will either dim, flicker or simply cut off when the voltage is getting too low.

In the beginning it might be helpful to use the light as normal and check the voltage occasionally and to make note of how the light responds when the voltage gets close to the level it needs to be for recharging. One other thing with unprotected cells, and lithium in general. With lights using more than 1 cell always make sure to use batteries charged to the same voltage, same age and same exact type to minimize any potential dangers of a voltage imbalance in one of them. This is usually what seems to cause the lithiums to vent in multi-cell flashlights; simple precautions as outlined above should definitely minimize any threat.
 

OttaMattaPia

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I just found the authentic KeepPower 26650's, protected 5200mAh batteries specifically for the L6 for 10.50 each and $4.00 total shipping for both so I went ahead ordered 2 of them.
Thanks for the pointer CelticCross74.

Illumn.com was the ticket :twothumbs
 
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TCY

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A general rule of thumb would be: If the flashlight doesn't have a built in protection circuit, don't use unprotected battery. (Unless you are an experienced li-ion battery user and know what you are doing)

You gotta have at least one protection mechanism to prevent feces from hitting the fan.
 

INFRNL

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Hope you ordered the right ones. The info above on length does not match what illumn states.

You ordered the longer ones which was stated wouldn't work and you need the shorter ones which are oos.

I'm not familiar with this light or the 26650's

I just happened to stop by. Either way, i hope they are not too long and work ok for you


Also, i have used unprotected cells in lights and other items without any protection circuitry without issue. Asking this question usually opens a can of worms and can lead to some heat. Luckily this hasn't been the case here
 
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TCY

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Also, i have used unprotected cells in lights and other items without any protection circuitry without issue. Asking this question usually opens a can of worms and can lead to some heat. Luckily this hasn't been the case here

I'm just going for the safest route here. If the battery is not over-discharged and handling too big of a current, everything is peachy.
 

etc

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The way I have understood it.over the years, it is ok to use non-protected cells in a single cell configuration. Because you visually see it decline. And swap before it is down below 2.5v.

In a dual cell configuration you wont see it coming since the voltage will be high enough yet each individual cell will dip into unsafe range. Below 2.5v. And cause permanent damage to cells.

I have used non-protected 18650s for 10 years with no issues but then I almost always recharge between 3.7-3.9v and I can almost visually determine that voltage.
 

CelticCross74

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my short Keeppower 5200mah 26650's measured just over 68mm long using my digital calipers. The long ones measured out over 71mm long using my digital calipers. I have noticed that it is rare when I get any cells that match the advertised specs exactly...
 

roadkill1109

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Hello!

I would just like to add that the reason it would be advisable to use protected cells in a flashlight such as this Convoy L6 is that lights which have batteries in serial, usually end up killing the cell closest to the circuit. I found this out using several lights that have batteries in serial such as the Crealant 7g5v2, the Fenix TK35 which I tried to use until low batt with unprotected Panasonic cells. When it did go low, I noticed that the first cell in the light was below the healthy voltage range (under 2.0 volts) so every since, I started using protected cells in multi-celled (in serial configuration) flashlights.

I recommend using the keeppower 26650 which was purposely shortened to ensure fit in the L6. Another one I have tried is the Enook (Vape 26650 protected cell).

You could use flat-top cells to ensure fit, just make sure the contact is not recessed as these will need to contact each other in serial.


good luck! :)
 

eff

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On a single cell flashlight with:
- a protection circuit, you can run you unprotected cells without worrying too much
- no protection circuit, you'll have to remove your batteries, to check the voltage

As for multi cells flashlights : don't put unprotected cells in there!!
 

Atmar

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On a single cell flashlight with:
- a protection circuit, you can run you unprotected cells without worrying too much
- no protection circuit, you'll have to remove your batteries, to check the voltage

As for multi cells flashlights : don't put unprotected cells in there!!
Manufacturer offered replacement. Even if I just stay on medium I can't run them? Tnx
 

Atmar

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Bcos what happened was I charged them inside the flashlight using a cell phone charger and when the indicator was green I took it off and turned it on. Then it quit. First just half Then 3/4 then nothing. I was thinking too much power burned the led chips.
 

staticx57

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Can you be a bit more specific with what lights and what happened? In general the danger is to the cell itself not the light (over discharge) If you are worried that using a high drain cell in a light that allows unlimited turbo levels, that is a function of using a high drain cell not a protected or unprotected.
 

Atmar

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Can you be a bit more specific with what lights and what happened? In general the danger is to the cell itself not the light (over discharge) If you are worried that using a high drain cell in a light that allows unlimited turbo levels, that is a function of using a high drain cell not a protected or unprotected.
is the cell im using high drain??? tnx
 
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