Battery Safety,Mech Mods,Resistance.

Dr Bill

Here's a quick guide to battery and coil building safety.
It may be here already and Admins feel free to delete or move if necessary.
It's made up of bits and pieces that I gathered from different sites but worth a read.

Batteries and Mech
So you recently purchased your first mechanical mod and then realized you had no idea that it took batteries or had no idea which batteries were going to be safe with it? First of all, congratulations on your first mech mod but, read this first: A Basic Guide for Mechanical Mods and Safety.
Already read it? Great, you’re definitely on the right track now and we’ll teach you as much as we can about batteries, battery safety, ohm’s law, and how to determine how safe your coil or atomizer/clearomizer/cartomizer is for the battery you are using.
With regards to vaping, the battery is the most important item, far more important than your coil, or multiple coils if you have them. Batteries are even more important than the debate over the superiority of wick materials (cotton, organic cotton, silica, mermaid hair – whatever). So if you are looking to get into mechanical mods, or thinking about pushing the limits of your current set-up, or are completely unaware of what your battery can even handle – then this article is definitely for you.
Battery Safety Basics
Do not overcharge or over-discharge.

To combat this, do not leave your batteries in any charger without supervision. Make sure that you are able to see or check on the charger every 15-30 minutes. This way when the charger indicates that the batteries have been fully charged, you can remove them from the charger. Leaving batteries in a charger all night long or longer can cause them to be overcharged, which can result in battery failure. Charging your battery over 4.25 volts can shorten its life-cycle and going over 4.5 volts can cause it to burst. Cease using your charger if this ever happens.
Our recommendation on a good charger: Nitecore D2 Charger (2 Bay) or Nitecore D4 Charger(4 Bay)
Recharge batteries with a resting voltage below 3.6V as soon as possible.
Leaving LiIon batteries in a discharged state will incur irreversible damage – creating a loss in capacity and a loss in cycles.
Determining the exact voltage can be tricky, unless you have a multimeter. If you are delving into the world of mechanical mods and RBAs (ReBuildable Atomizers), or making your own coils, a multimeter is a must have device because you can use it to test your coils and your batteries. Sure, you can always use a battery tester, but the majority of battery testers are not equipped for the types of batteries that are used in mods, or even test batteries under load condition.
Do not short circuit your batteries.
Short circuiting can cause a huge surge of current that will potentially burn out your battery, damage your mod, or even your face!
Short circuits happen when the voltage from a battery is discharged through a low resistance wire at a discharge rate that exceeds the battery’s upper amp limit. Short circuiting a battery is very close to what a mechanical mod with a sub-ohm coil is doing, except you are trying to keep the resistance under the upper amp limit – there’s a fine line that you have to be careful of when sub-ohming.
Do not let your batteries touch each other or other metallic items.
Keeping your batteries loose, such as in your pockets, is a good way to have your batteries fail and seriously harm you. There are battery holders and covers to keep your batteries safe. Get some – now.
Do not dispose any battery in a fire.
This is just common sense people. There are dangerous chemicals in batteries. If you try to burn your batteries they’ll release dangerous fumes and will probably explode. Do yourself, and the rest of the world, a favor by taking your old batteries to a battery recycling center.
What’s In a Name?
Let’s take a look at the specifications of AW IMR batteries for a moment:
IMR16340 Specifications:
Nominal Voltage : 3.7V
Capacity : 550mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 1.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 4A
Operating Discharge Temperature : -10 – 60 Degree Celsius
IMR14500 Specifications:
Nominal Voltage : 3.7V
Capacity : 600mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 1.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 4A
Operating Discharge Temperature : -10 – 60 Degree Celsius


IMR18350 Specifications:
Nominal Voltage : 3.7V
Capacity : 700mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 2A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 6A
Operating Discharge Temperature : -10 – 60 Degree Celsius


IMR18490 Specifications:
Nominal Voltage : 3.7V
Capacity : 1100mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 3A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 15C
Operating Discharge Temperature : -10 – 60 Degree Celsius
IMR18650-1600 Specifications:

Nominal Voltage : 3.7V
Capacity : 1600mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 4.5A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 15C
Operating Discharge Temperature : -10 – 60 Degree Celsius
IMR18650 -2000 Specifications:

Nominal Voltage : 3.7V
Capacity : 2000mAH
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 2A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 10A
Operating Discharge Temperature : -10 – 60 Degree Celsius


Determining Your Maximum Discharge Rate
The most important specification to pay attention to is the “Max. continuous discharge rate” for each battery. Each battery has a number and a letter, either measured as A or C (30 Amps or 15C). Look at the IMR18650-1600 for example. If your battery has a maximum continuous discharge rate of 15C, this means the battery is rated for 15 times the capacity of the battery measured in amps. So a battery that sits at 1600mAh, which equals 1.6Ah will have a max continuous discharge rate of 15 X 1.6 = 24A. There is a chart below which has the max continuous discharge rate in Amps of some common batteries.
You should always determine what your max continuous discharge rate is in Amps (which many of the new and popular batteries have already) to keep your math consistent and mind at ease.
How To Use This Information Effectively
Knowing the max discharge rate in amps is only half the battle.
How do you know if your coil or atomizer/clearomizer/cartomizer won’t short circuit your battery? Simple, use this equation: battery volts / the ohms resistance of your coil = your actual discharge rate.
If your actual discharge rate is less than the maximum discharge rate you calculated earlier, you’re in the clear. If it’s not, you need to suck it up and rebuild a higher resistance coil.
Let’s take a closer look using the 18650 1600mAh battery again (for the sake of continuity). If you took a freshly charged 18650 1600mAh battery and tossed it in your mechanical mod with a very limited voltage drop, and put a .2 Ohm coil on top, you’d be running at 20 amps. To figure out this math you take the voltage running to your coil from your battery, which lets say after a full charge, the multimeter shows that the battery is sitting at 4 volts. Now, divide by the ohms of your coil. The number you get is your total amps. In this case our math is 4/0.2 = 20. So we now know that running this exact setup will push our battery to 20 amps, just 4 amps under its max discharge rate. If you were using a different battery capable of less power under the same circumstances, you would be asking for complete battery failure and the chance of possibly hurting yourself.
Safety PSA: Resistance in coils can have a variance of 0.2 Ohms in either direction, or +/- .2 Ohms. This means that if you build a 0.2 Ohm coil, you have to account for that +/- 0.2 Ohm variance. The coil in the above example at .2 Ohms is an incredibly unsafe coil, and I would not use nor suggest that anyone use such a coil. Because of this, I would not recommend anything lower than a 0.4 Ohm coil for 18650 1600mAh battery.


Equation Recap
Let’s take a look at everything you’ll have to calculate in order to determine your coils safety in order.
1. Calculate your battery’s capacity in amps: capacity in mAh / 1000 = capacity in amps
2. Calculate the maximum discharge rate if measured in C: maximum discharge rate = (battery capacity in amps) x (continuous discharge rate)
2. Measure your battery’s volts with a multimeter.
3. Measure the Ohms of your coil and subtract .2 to account for the +/- .2 variance.
3. Calculate the discharge rate you’ll have with the coil you’ve built: battery volts / Ohms = your actual discharge rate
4. Check to make sure that the actual discharge rate is LOWER than your battery’s maximum discharge rate.


The best batteries for sub-ohm vaping are generally Sony VTC 4 or Sony VTC 5, although they are often out of stock,or i find the samsung 25r a capable battery

Didihno

Brilliant.

Ionised

Great post.
A quick postscript - please folks don't cheap out on batteries and ensure you get the real thing.
We all were happy to spend a tenner on a packet of fags so why not spend the same on a proper battery that will last a hell of a lot longer.
Apologies if this sounds a bit ranty!

Didihno

Ionised wrote: »

Apologies if this sounds a bit ranty!

Not at all. It's vitally important in fact.

And not trying to be controversial here, but beware fake Sony VTC5 (and 4) batteries, even sold by reputable dealers (who either don't know any better or are told by their suppliers that they are genuine). That's not to say these batts aren't ok, I have several and they seem to be fine, but I am dubious as to their authenticity.
There is some evidence out there somewhere that these have not been manufactured by actual Sony for years. LG, Samsung and Panasonic all make their own units I believe. Other brands, such as efest, trustfire etc, seem to be rewrapped 'low' grades, i.e. rejected by the manufacturer as being not quite up to par and sold as B stock.
Finally, beware these batteries claiming to be super high amp 'sub ohm' cells etc. There are folk testing these cells and finding them to be anything but. 'Battery mooch' (cited by GrimmGreen) I think is one guy?

corsav6

Excellent post Dr Bill, I'm sure it will help a lot of people out.

jno547

Got this in a newsletter,worth a read.

We have noted a number of reports in the media recently regarding damage to property or persons that were allegedly caused by e-cigarette batteries.

It should be mentioned at the outset that in incidences where a property is damaged and an investigation by fire officers is reported on, the use of incorrect chargers for the specific model of vaping device or leaving the battery to overcharge has frequently been the cause.

In some cases, the cause can be attributed to sub standard quality batteries where quality control has not been applied in the manufacturing process.



Always read instructions

Like all lithium ion batteries, such as those in laptops, mobile phones and tablets, the correct discharging, charging and storage of batteries ensures consumer safety.

Provided instructions should always be strictly adhered to. If none have been provided, contact your vendor for advice.

Never leave charging batteries unattended

In the case of smaller and ‘ego style’ batteries, only the corresponding charger with the correct amp rating for the battery should be used.

Batteries should never be left unattended while charging, and should never ever be left on charge overnight.

Always unplug the charger and remove the battery immediately after the battery has reached full charge.

Batteries should never be placed on soft furnishings or carpets while charging.

Charging bags are available that encase the charger and battery during re-charging and provide additional safety.

Use 3rd generation batteries and rebuildable atomisers safely

In the case of larger ‘3rd generation’ batteries, only high quality chargers with an automatic charging cut off should be used.

Batteries should never be discharged below 3.2 Volts or overcharged above 4.25 Volts.

If the battery is being used in a ‘mechanical’ device, only the correct atomiser resistance should be used for the amp rating of the particular battery.

An understanding of Ohm’s law is necessary to safely set up a ‘rebuildable’ atomiser.

Our members recommend these products are only used by experienced consumers who fully understand battery safety thresholds.

Batteries should always be stored safely, in plastic battery containers where the contacts cannot touch each other.

Never allow the contacts of batteries to come in to contact with metal keys or coins etc. This can lead to short circuits occurring and cause the battery gases to vent.

Never use a battery when the plastic covering is torn or damaged. Replace it instead

Most specialist vape shops sell battery cases, and for the sake of a euro or two e-cigarette users can have peace of mind they’re taking proper precautions.
Lithium ion batteries, when used correctly and stored safely aren’t dangerous, and vaping is proven to be less dangerous for you than smoking.

moleyv

Just to give my thoughts in support of all the great advice above.

I've had a charging bag a long time but only recently started using it.

I use a nitecore charger and never charge unattended.

Thing is, if you are in attendance, yes you can deal with it quicker, but a large amount of damage could already be done, let alone the risk of flying shrapnel causing personal injury.

So for the few euro the charging bag costs, and the few extra seconds it takes to put the charger inside, it is well worth it.

The 'explosion' would be mostly contained by the bag.

Also, recently another battery caused someone burns, the article blamed Efest batteries. Now I'm not a fan of Efest, and discourage people buying them, but near the end of the article we see the real reason it exploded....

It was left loose in her handbag. ...

Silicone battery sleeves or plastic cases are so cheap.

28srf0c

I read somewhere to never let your battery drop below 3.2v I think it was. But I vape at a low wattage, and right now I'm reading 2.91v. (5.5w on a 1.54ohm coil).

Is this going to explode in my face?

grindle

28srf0c wrote: »

I read somewhere to never let your battery drop below 3.2v I think it was. But I vape at a low wattage, and right now I'm reading 2.91v. (5.5w on a 1.54ohm coil).

Is this going to explode in my face?

In your regulated mod the voltage is being lowered by the chip. The battery inside isn't dropping below 2.91v (your mod would turn off because of the weak battery), the display is just telling you what's being delivered to the coil.

Increase your wattage and you can watch your battery's voltage magically increase.