Charging unprotected 21700

I recently bought my first unprotected cell, a Liitokala 21700, which came with a Convoy M21F light. I am using a Xtar VC4H charger. Do I have to take any special precautions when charging this unprotected cell? At present it’s charging in my sitting room. I could always use my VC4 charger and charge it in the porch on a tiled floor.

I know the Xtar chargers have a good reputation but there’s been more than a few house fires when charging lithium cells, doubtless due to poor quality or faulty chargers.

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Not different from a protected battery if you use a good charger like the XTAR.

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Keep in mind that lithiums should not be charged at sub-zero (Celcius) temperatures

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I try to not leave unattended (not charge overnight) and not charge on too easily flammable stuff. Like a table is fine, a bed is not. But opinions vary a lot…

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With a protected battery there are two protection mechanisms i.e. in the charger and in the battery. If one fails, the other acts as a backup. With an unprotected cell you’re relying on the protection circuitry in the charger to always work.

I have no idea how reliable these circuits are. I do have house insurance, but still, I’m not keen on watching my house burn down.

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Yeah. Also I sometimes check the batteries’ temperature.
Once I had a battery that were getting too hot when being charged. It turned out it were getting warm even when resting and it were loosing charge (probably due to internal short).
I had made a minor dent on the battery, so it probably was my fault.

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My porch is very rarely below zero Celcius, but it’s a very good point. Thanks.

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These type of chargers and batteries are in the market for many years, and the accidents are very low (and when they happened, we don’t really know the real reasons and conditions… !?) !

Probably there is no real reason to be afraid , but its a good thing to be careful and keep an eye on them while they are charging !

Li-ion batteries they don’t like very low or very high temperatures, i think it’s better to put them in bathroom and charge them, and everything is going to be just fine !

Just my opinion !

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Every case I know involved third party camera batteries and hover scooters imported from China, so basically poor quality items. I’ve never heard of an issue with an Xtar chargers, no idea about Liitokala.

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True true !

I had a XTAR VP2 Charger for many years (probably 10+) and i never had any problem ! Now i have the Vapcell S4 Plus V3 for one year and im very pleased with it ! In general lines the are very good chargers, and with good features and protections !

Im using unprotected flat-top batteries (mostly 18650) and i never had any problem too (always very careful use, and keeping an eye on them) !

About the Liitokala, i know that they have some very nice chargers, and i never heard anything bad thing about them or for their batteries !

https://liitokala.com.cn/aboutus

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I usually verify that a chargers cut off voltage isn’t too high 4.2 v max. I also charge more on the conservative side, .5c max. Most of the time 1.5 amp 21700 – 1 amp 18650 – .5 amp 16340/ 14500
I tend to not like auto choice chargers, I find they charge at too high of amperage ( my preference )

Use these steps along with others mentioned, you’ll be good to go

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Don’t forget that the protection on the battery itself adds another mode of failure. There’s a wire/strip on the side of the battery that goes to (+) to power the circuit and that can easily cause a short circuit if it were to get damaged. Can’t happen with an unprotected cell.

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I assume you mean if the wrap is damaged, potentially allowing a short circuit. Isn’t that why we should either discard or rewrap cells with a damaged wrap? I’d rather have a protected cell, but that’s just my preference. Each to their own.

As an aside, I realised that my Convoy M21F has built-in USB charging, hence I can charge it in my porch without having to move my charger there. It’s probably quite a low charge current, hence beneficial, and reports indicate that it terminates at 4.1 V, another plus.

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I think it’s better to not use the build in charging port, its way better on a external charger… !?

You just bought a cell from a re-wrapper. You don’t even know what cell exactly was randomly recycled and re-wrapped, yet you’re worried about charger.

Liitokala have a good reputation here and elsewhere, and the cells HKJ reviewed test well.

What is your objection to the internal charger?

My question is academic though, as I ordered an Xtar VX4, the Xtar VC4H will go in the enclosed porch for unattended charging, albeit when the weather improves.

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Funny that from what I see around they don’t have good reputation (speaking about cells, not chargers). As for test/review - will the next batch be the same? Liitokala has even different specs (and of course no data sheets) on their different regional sites for same cell. That’s good reputation in your books? I mean it’s your money and safety, however it’s lower than my acceptable standards and I am a budget buyer.

First of all, the usb port on the flashlight is a pontecial failure point, after a while the port is getting loose and end up with out to be able to make a proper connection ( something similar like the phones do) ! And when you are charging all the current goes through the flashlight’s board, and your are “forcing” all this power / heart in the circuit for quite a few hours that the charging takes ! Plus when you are charging in the flashlight you can’t see and control/monitor anything, everything is closed up in the flashlight !

On the other hand, with an external battery charger, you don’t “forcing” anything into flashlight (it doesn’t get any extra “stress” from the charging process), and on the external charger you can check out almost everything that is happening ( temperature, resistance, current, how much time are you charging… etc… )
For example :
My Fenix WT25R has a magnetic charging system, i tested once, just to see that is working properly and i never change it again, im keeping it in good condition as a “spare” for when i.m gonna really need it… !

So for me is way better the external charger !

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What you say makes sense, I’ve rarely used a built-in charger anyway.

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