Battery Safety on Mech Mod

[jamal01]

Hey

So I have been researching to get my first mechanical mod. I understand the most important is the testing. Checking to ensure batteries are correct voltage, checking coils for shorts, etc.

However I had a question when testing the limits of my batteries.

From my research I know that I have to use IMR batteries and need to ensure that my build (ohms) is such that the watt is not exceeding the amp output of the battery.

What I am confused about is how do I calculate what the voltage of my mech mod would be? I am too used to my VV/VW devices that just say it. Would it just be the voltage of the battery?

I am using authentic samsung INR18650-25R (3.6 V, 20 amp MCD, 35 PV)

My mech mod runs 2 of these in series.

Any help will be appreciated, I am new to mechanical mods so making sure I am being as safe as possible! Have already experienced a house fire (unrelated to vaping or lack of safety!) and would not want to experience something like that again, especially if I cause it!!

 

[HecticEnergy]

correct - voltage comes from the battery. Even in your regulated mods they are just reading the battery voltage.

make sure you don't exceed your continuous amp rating on the battery (20 amps for your samsungs - which are good batteries if the people here are to be believed lol)
you don't NEED to use IMR batteries (technically) - they are just safe chemistry batteries with higher amp ratings. If a dead short does occur the battery is LESS LIKELY to explode - that doesn't mean it won't, just that it's less likely
Cheap ohm testers are accurate to +- 1ohm, so make sure you have a good quality ohm meter / multimeter if that margin of error will cause you to draw more amps than the continuous rating on the battery (20 amps)
You probably know all that from your research, but better safe than sorry

Glad you are doing your research before hand!! Kudos to you

And Welcome to the Forum!

 

[Robert Dupre]

Ok when using 2 batteries if it correctly ran in the mech like how some people make there own then it can be a lil more dangerous but its actually simple but being its 2 batteries then you actually have double the amp out put because it should be pulling equal amounts of power from each battery so if it is a 20 amp continuous rated battery you should be able to pull 40 amps continuous with 2 parallel batteries. But you still would want to keep a lil below you continuous rating for safety reasons with one battery i dont build lower than .3 ohms which is 14 amps out of 20 but the lowest you possible with out going over is .21 ohm and that is exactly 20 amp but not suggested to do.

 

[HecticEnergy]

Thanks Robert for clarifying on the stacked batteries - I'm not knowledgable on such things.

 

[Rickajho]

I think you may be a little lost about the voltage issue moving from an electronic VV/VW to a mechanical. Your voltage is whatever is coming directly off the battery. For new batteries, when freshly charged they start at 4.2 volts and voltage drops from there with use over time. If you are looking at ohm's law calculations you may want to do it twice - at 4.2 volts when a battery is freshly charged and at 3.7 volts when you will most likely be pulling the battery to recharge it.

For most IMR chemistry batteries your safe low limit when discharging is 2.5 volts. Below 2.5 volts is when you start damaging the battery by putting, for lack of a better way to put it right now, 'chemical breakdown stress' on the battery. For IMR's this isn't traumatic - but dropping the battery voltage below 2.5 volts repeatedly will shorten the useful lifespan of the battery. It's seldom an issue as most people really begin to notice a dropoff in their vape performance when you hit even 3.7 volts and want to recharge at that point anyway.

 

[Rickajho]

Hey

So I have been researching to get my first mechanical mod. I understand the most important is the testing. Checking to ensure batteries are correct voltage, checking coils for shorts, etc.

However I had a question when testing the limits of my batteries.

From my research I know that I have to use IMR batteries and need to ensure that my build (ohms) is such that the watt is not exceeding the amp output of the battery.

What I am confused about is how do I calculate what the voltage of my mech mod would be? I am too used to my VV/VW devices that just say it. Would it just be the voltage of the battery?

I am using authentic samsung INR18650-25R (3.6 V, 20 amp MCD, 35 PV)

My mech mod runs 2 of these in series.

Any help will be appreciated, I am new to mechanical mods so making sure I am being as safe as possible! Have already experienced a house fire (unrelated to vaping or lack of safety!) and would not want to experience something like that again, especially if I cause it!!

Are you sure about that? It's highly unusual to find a mechanical running 2 batteries in series these days.

 

[Robert Dupre]

Wait a sec i didnt say anything about stacked batteries and if it is stacked i wouldnt use more than the continuous amp rating of a single battery but i think that would looke simular to a light saber if 2 18650 batteries where to be stacked inside of a mod. What mod are you using if it is a box then you may just be unfamiliar with term and this post has nothing to do with you.

 

[Robert Dupre]

But in series in the same way as the ivp3 or siegelei does then you have double the amp limit if it its put together correct

 

[Robert Dupre]

Yes if it pulls it power from both equally then you will have up to 40 continuous amps available but you wont need to even build that low of resistance unless you for some reason decided to enter a cloud comp

 

[philoshop]

A stacked arrangement is a 'series' connection. Voltages are added together.
In a 'parallel' connection the amperages are added together.

 

[Susan~S]

Hello and welcome to the forum. Glad to have you here!

Two batteries in a series (stacked or wired as such) doubles the voltage while maintaining the amps/mah of one individual battery.

* With 2 batteries in a series their combined voltage would be => 4.2v + 4.2v = 8.4 volts on a full charge. Running stacked batteries is generally not recommended. Batteries need to be married, marked & rotated in the charger/mod, etc. In the past modders (with experience in batteries) sometime wire mods as such but they know EXACTLY what is going on with their batteries when doing so.
However today there is no need to do so with all the high vv/vw mods available. You are more likely to see modders wiring batteries in parallel to double the amps/mah.

What mechanical mod are you using that takes 2 stacked 18650 batteries?

==========

If you are new to mech mods and rebuildables I highly recommend you spend some time with Baditude (one of our resident battery experts) and visit his blogs. You are now 100% in control of your own safety (and others around you). Make sure you purchase an ohm reader and a voltmeter or DMM so you can measure your builds, check for shorts and measure the remaining charge on your batteries.

Baditudes Blogs. The blogs regarding mods and rebuildables are listed below:

BATTERIES

9. Battery Basics for Mods: IMR or Protected ICR?
* Another essential read to understand which batteries are safe to use in mechanical and regulated mods. Includes a frequently updated list of recommended safe-chemistry, high-drain batteries with their specifications.

17. Purple Efest Batteries Not As Advertised
* A cautionary blog that reveals that the purple Efest batteries may not have the specifications advertised. Also includes a commentary on "continuous discharge ratings" vs "pulse discharge ratings" of battery specs.

OHM'S LAW

14. Ohm's Law for Dummies (Vapers)
* My attempt at explaining Ohm's Law in layman terms and how it relates to vaping.

16. Explain it to the Dumb Noob: Ohm's Law Calculations
* As simple as it is to use, some people have a tough time grasping the concept. Warning: Includes graphic photos of mod explosions.

MECHANICAL MODS & REBUILDABLES

7. Information Resources for Your First RBA
* An essential read and reference guide for someone new to rebuilding coils. Includes a multitude of useful links on battery safety, mod safety, coil meters, coil building, and the differences in the three types of RBA's.

15. Inexpensive Mechanical Mod and RDA Setup
* A response to the frequently asked question on how to get into rebuildable atomizers with a mechanical mod inexpensively. Includes a list of commonly used tools and supplies for rebuilding and where to find them.

BATTERIES - WHERE TO BUY

Only buy batteries from a reputable supplier (not ebay or Amazon) as there are many counterfeit batteries being sold. Here are several reputable battery suppliers in the US.

* RTD Vapor
* Illumination Supply
* Lighthound
* Orbtronics

 

[readeuler]

Yes, to clarify: if your mech really uses two batteries in series, you will not want to draw more than the CDR of a single battery, 20 amps.

This means your resistance needs to be at least 2*4.2/20 = 8.4/20 ~ 0.42 ohms.

This isn't a huge deal, as you'll still get pretty significant wattage (before voltage drop), with even a 1 ohm coil, probably around 70 watts.

ETA: I know someone around here, Norrin, uses a mech with two batteries in series (a box, they seem to be somewhat popular, at least I'm seeing more at retailers) and he gets along fine, from the sound of it. He does keep his builds around an ohm, I believe.

 

[jamal01]

Are you sure about that? It's highly unusual to find a mechanical running 2 batteries in series these days.

sorry it was late last night and that was a typo. I meant to type it is in PARALLEL not series.


Thanks to everyone for their response! And thanks Rickajho for pointing out to do 2 calculations - one for either end of the voltage spectrum.

So just to get a double check because you all seem so nice =)...

samsung INR18650-25R ...running 2 in parallel...

Calculations done @ 4.2 V and 3.7 V

2 batteries will give me 35 amps (I know 40 was mentioned but dropped it to be safe)


From what I am getting as long as I stay above 0.12 I should be good?

 

[jamal01]

Sorry you are correct =), bad wording on my part...I meant since I am a newbie I am likely safer off with IMR =)

 

[HecticEnergy]

sorry it was late last night and that was a typo. I meant to type it is in PARALLEL not series.


Thanks to everyone for their response! And thanks Rickajho for pointing out to do 2 calculations - one for either end of the voltage spectrum.

So just to get a double check because you all seem so nice =)...

samsung INR18650-25R ...running 2 in parallel...

Calculations done @ 4.2 V and 3.7 V

2 batteries will give me 35 amps (I know 40 was mentioned but dropped it to be safe)


From what I am getting as long as I stay above 0.12 I should be good?

Better safe than sorry! I like it not experienced with dual battery mods, so don't take my word on it
Sony Vtc 4s have a lower mah rating but are 30amp if you wanna go lower ... 55amps (with your safe -5 amp margin of error) using that calculation!
IMR is safe chemistry so they are less likely to vent.. Everyone should be using these and in vented mods


Sent from my iPhone 6 using Tapatalk

 

[KenD]

From what I am getting as long as I stay above 0.12 I should be good?

Note that very few ohm readers are accurate at that low a resistance, and even 0.01 ohm lower than the reading makes a huge difference when you're that low.

 

[jamal01]

The meter I use has a resolution of 0.1Ω - 0.001MΩ and a accuracy of +/- 1%


I don't plan to go below 0.2 - but just wanted to check.

it wasn't too long ago that I didn't expect to go below 1.0