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Battery safety question: when to change batteries in mech mods...

Mesh

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So after vaping for years with regulated devices, I've just ordered my first mechanical mod (Wotofo Phantom) and I added two Samsung 25r batteries to the order.

My question is: how do I know when to change the battery inside the mod? I've heard people say 'You'll know to change when you stop getting good vapes, etc', but I just wanted people's opinions on the safest way to go about this. Apologies for the newbie question, but do these batteries have any safety features to stop them from over-discharging and any other mischief?

(I've been successfully building sub-ohm RDAs for a few months, but only using them on regulated devices.)

Any tips and pointers much appreciated!
 

NemesisVaper

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People's opinions differ somewhat on what is a safe discharge level. Regulated mods will take a cell down to around 3.2V. I've heard people say you need to change batteries in a mech at 3.7V, which to me doesn't make much sense. A regulated mod applies a load to the cells just the same as a mech does. The difference is the regulated device will tell you when your cells are at the cut off, a mech will fire regardless.

Your Vape will start to become noticeably weaker as the cell discharges. For most, they'll feel the need to change cells way before they reach the level that you need to for safety reasons. Safety wise, 2.5V under load or 3.0V resting is the minimum voltage you should be taking them to. That is a little too low for me. I'm happy to see 3.2V or higher.

Most of my cells go on charge around 3.4V. This is just from me not wanting to Vape that cell anymore as it's not vaping how I want it to. I recently moved down from regular 0.23 ohm (approx) builds to more like 0.17 ohm. With that I was getting way more wattage at where I'd usually charge a cell, so I saw a few batteries at 3.1-3.2V. That didn't last long, as I re learned and my tastes changed, they went back on the charger at my usual 3.4V.

If you're in any doubt, switch batteries. A multi meter / combined ohm meter volt meter or charger with voltage display are essential in my opinion. When you feel the Vape drop off, check the voltage of the battery. This way you'll learn what a Vape at a certain voltage feels like on the build you like and can learn to judge pretty much spot on when you must change batteries. Of course, if you like a strong Vape feel ree to change them as often as you like.
 

Jon@LiionWholesale

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Just to add one thing, no there aren't any safety features in an unprotected battery so do be careful! Keep in mind you can get a solid basic multimeter from harbor freight for like $2 or something, sometimes even free with a coupon. Check the voltages so you can get a feel for what different voltages feel like.
 

Ryedan

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My question is: how do I know when to change the battery inside the mod? I've heard people say 'You'll know to change when you stop getting good vapes, etc', but I just wanted people's opinions on the safest way to go about this. Apologies for the newbie question, but do these batteries have any safety features to stop them from over-discharging and any other mischief?

(I've been successfully building sub-ohm RDAs for a few months, but only using them on regulated devices.)

Any tips and pointers much appreciated!

That's a very good question :)

I vaped mechanical mods a lot more than regulated until early this year. Here's my take on it.

With a bit of experience with mech mods you can generally tell when battery voltage gets to about 3.6V no-load. OTOH when I first started using mech mods I occasionally ran a battery down to around 2.5V or so no-load, which is not good for the battery.

When you start using mech mods check battery voltage often. Not every five minutes, but hourly at first is probably a good thing. Get to know how the vape feels as your battery discharges over a few discharge cycles. Voltage will drop from 4.2 to 3.9V fast, stay in the 3.9-3.7V range for a lot longer and then drop fast again. The problem is once it starts to drop fast you might miss the quick change and let it drop too far. Once you get a feel for this you will realze it's happening and will swap batts appropriately.

Having a DMM that you can use to check battery voltage with is important and as Jon said they are cheap.

HTH
 

Mike H.

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I tend to go no lower than 3.5 to 3.6v

The lower the voltage the more of a load that is placed on the battery creating more heat which is very bad for batteries in general and, only hurts battery life in the long run.

Technically, you can go lower but, to me the vape sucks below 3.5 to 3.6v anyways.
 

Mike H.

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Consider this...the voltage to the atty with the battery fully charged is sending around 3.8v to the atty based on for example using a .5 ohm coil (s)

So, by the time the actual battery voltage is around 3.6v you have very low voltage going to the coil..Who vapes at 3.2 volts to the atty on even a regulated device?

If i set my wattage on my regulated to give me 3.2v to the atty the vape flat out sucks compared to 3.6v or higher.
 

Mesh

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I really appreciate the excellent responses. I'll get a multimeter asap.
 

Mesh

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Consider this...the voltage to the atty with the battery fully charged is sending around 3.8v to the atty based on for example using a .5 ohm coil (s)

So, by the time the actual battery voltage is around 3.6v you have very low voltage going to the coil..Who vapes at 3.2 volts to the atty on even a regulated device?

If i set my wattage on my regulated to give me 3.2v to the atty the vape flat out sucks compared to 3.6v or higher.

Yeah that's the way my brain is relating to this, by comparing it to regulated devices. 3.2v at .5 ohms would be a measly 20 watts. You'd get hardly any vapour production, especially if you're used to vaping at 45-50 watts.

So I'm kinda reassured that you'd have to change the battery before it reaches unsafe levels of discharge, simply because the mod wouldn't be producing vapour anywhere near satisfactory levels.
 

Mike H.

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Yeah that's the way my brain is relating to this, by comparing it to regulated devices. 3.2v at .5 ohms would be a measly 20 watts. You'd get hardly any vapour production, especially if you're used to vaping at 45-50 watts.

So I'm kinda reassured that you'd have to change the battery before it reaches unsafe levels of discharge, simply because the mod wouldn't be producing vapour anywhere near satisfactory levels.
Exactly.
 

Mike H.

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Im just figuring the same amount of "voltage drop" throughout the actual batteries voltage...With a fresh charged battery that gave me 4.2v i saw around 3.8'ish voltage at the atty with a .5 ohm coil...So im just assuming as battery voltage drops id lose the same percentage to the atty...20w with a .5 ohm coil sucks...i need around 26 27 watts on my orchid hybrid tanks and 30 or higher for my rda's...lol
 

Mesh

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Im just figuring the same amount of "voltage drop" throughout the actual batteries voltage...With a fresh charged battery that gave me 4.2v i saw around 3.8'ish voltage at the atty with a .5 ohm coil...So im just assuming as battery voltage drops id lose the same percentage to the atty...20w with a .5 ohm coil sucks...i need around 26 27 watts on my orchid hybrid tanks and 30 or higher for my rda's...lol

Yeah, 45-50 watts is just for the RDAs. For the kanger subtank at .5 ohms, I find 18-23 watts works best without burning the cotton within a couple of days.
 

NemesisVaper

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Depends how low you build. 3.2V at 0.17ohms is 60W. Assuming the 3.2V being an under load voltage, that's plenty of power. The lower ohm build will usually have less metal than something built to even 0.3 ohm with thinner wire.

For me, anything built 0.25 and above goes on a regulated device. With a mech you have to consider the wattage you'll be getting throughout the life of the battery and build accordingly. With the right build and thickness of wire, shooting a little higher wattage than you'd Vape regulated will alow you to take advantage of the battery more. You'll need to shorten draw time with a fresh cell, then increase it as the cell drains.

Talking about specific ohm builds brings the safety question into more of a general question and adds a massive amount of variables. With a volt meter, regular testing and a bit of time, everyone will develop a sense of what they need to do and when.

A battery won't be under more strain as voltage drops. It will be under less strain in a mech. The lower the voltage the slower the flow and the less current will pass. In a regulated device, the opposite is true, because as flow drops the board will increase the load to be able to continue to provide the set wattage.

Definitely important to be careful. Not so much of a concern regarding battery longevity though. Look after them as best you can, but don't feel any need to be too gentle with them. As long as you're safe with them, use them as you need to. They're a very very cheap item when compared to juice etc. I've been impressed with all the cells I've bought, as to how well they've aged.
 

battery bro

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Keep in mind if you are draining a 25R at 20A it will last about ~200 charge/discharge cycles in a mod. The degradation speed increases when going at higher currents like 35A. In the latter case you can expect half as much usage.

If you're chain vaping and getting things really hot you will also stress the cell and shorten its overall life.

Your battery life can be determined by its capacity. You will notice the time it takes to discharge down to your minimum voltage (maybe ~3.2V) is shorter and shorter. There is no harm in continuing use at this point. It is just up to your preference. If you are only getting 15 minutes of good use, the battery becomes useless (but not dead).

You can consider your batt dead if it won't hold a charge at all, or has some other visual defects like rust accumulating.
 

Ryedan

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There is no harm in continuing use at this point. It is just up to your preference. If you are only getting 15 minutes of good use, the battery becomes useless (but not dead).

You can consider your batt dead if it won't hold a charge at all, or has some other visual defects like rust accumulating.

I've always thought that as these batteries lose capacity (mAh) they also heat up more at the same amp draw. What am I missing battery bro?
 

battery bro

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You can think of it like this.

As the cell ages it becomes less efficient at shunting lithium ions back and forth. This inefficiency is expressed as heat loss. In other words, the non-workable energy in your battery, which is lost, becomes heat.

That's why older batteries tend to heat up more. The problem is that using heat to measure quality of your cell is difficult. First, measuring heat is tricky and you need tools (not just feelings), second it is not necessarily a 1:1 ratio or linear difference. End-users can use heat to determine when the cell has had too much (eg. it surpasses 60 degrees C).

That's why total capacity rather than heat, as determined by discharge tests is the best way to determine the age of a cell. Hope it helps ;)
 

Mesh

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Keep in mind if you are draining a 25R at 20A it will last about ~200 charge/discharge cycles in a mod. The degradation speed increases when going at higher currents like 35A. In the latter case you can expect half as much usage.

If you're chain vaping and getting things really hot you will also stress the cell and shorten its overall life.

Your battery life can be determined by its capacity. You will notice the time it takes to discharge down to your minimum voltage (maybe ~3.2V) is shorter and shorter. There is no harm in continuing use at this point. It is just up to your preference. If you are only getting 15 minutes of good use, the battery becomes useless (but not dead).

You can consider your batt dead if it won't hold a charge at all, or has some other visual defects like rust accumulating.

Thanks man. Btw, this was very helpful when I was looking for some reassurances about the Samsung 25r http://batterybro.com/blogs/18650-w...-fake-18650-battery-featuring-the-samsung-25r
 

NemesisVaper

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@battery bro off topic I know, but could you clarify in your recent HG2 test you stated cutoff voltage officially is 2V not 2.5, so LG can achieve stated capacity. A fellow forum member here gave me a link to an LG spec sheet stating it is in fact 2.5V.

Ive recently tested the Koopor mini 60W single cell device and found the HG2 gives identical vaping time (puff counter shows seconds vaped too) to a HE4 and 25R plus or minus a bit.
 

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