If a battery is rated at 3.7v and 2600ma I assume you have to use ohms law to find out what resistance you need to keep Voltage at 3.7 or lower. Is this correct? Do your coils lose resistance over time?
Battery questions
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so you would have to build a coil at less than 70ohms? As your resistance increases your voltage decreases resulting in less vapor? Can you check a coils resistance periodically with a multimeter?
No you got it wrong. The battery starts out with a full charge at 4.2 V. As it is used the voltage continues to drop (3.7 volts is the "nominal voltage", where the voltage sits during the majority of discharge curve) until it need to be recharged 3.2V. The mAh is the capacity....more mAh the longer it will last. There is also a maximum amperage value. How much the battery can handle.
You want to keep your coil resistance such that you are not overloading the amount of amps a battery can handle. The battery voltage will change along with the amps. The resistance will remain constant.
I think I got that right
I'm sure someone can explain it better. It all make sense in my mind LOL- Dirk
Your coil should not change any significant amount over the course of use
You sound confused about battery voltage, coil resistance, and how to figure the amperage (current) draw a coil will pull from the battery.
Ohm's Law for Dummies
- First of all, you'll need to know your battery's amp limit in continuous discharge rate: Battery Basics for Mods.
- Next you'll need to measure your coil's resistance with either a ohm reader or digital multimeter.
- Then you can use the Ohm's Law Calculator to find the current draw the coil will pull from the battery. Always use 4.2 volts for the voltage (fully charged battery) and fill in the ohms measurement for the resistance. Click calculate.
- The "current" will be the amps the coil will pull from the battery. This figure must not equal or exceed the amps of the battery or the battery will go into thermal runaway.
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It's commendable that you are asking questions, but I caution you to do more research before getting into RBA's. The questions you are asking indicates you are not ready to venture into this presently. Get a firm understanding of "why" and "how" we do the above procedures. Build your first coils at normal resistances (above 1.0 ohm) before attempting anything sub-ohm (below 1.0 ohm).
Information Resources for Your First RBA
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If you can fit a Vape Safe Fuse into your mod's battery compartment, I highly recommend doing so. A mech has no built-in protection circuitry like a regulated mod has, which will prevent it from firing during a short circuit. You need all the protection you can get in a mechanical, so a fuse is an excellent idea. These fit via magnet onto the negative end of your battery.
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Battery spec sheet. Use IMR high drain cells. Efest, AW, Sony
I suggest doing some research and study here about batteries and coils
- Dirk
If you check the links i posted in your other topic ull get all these answers 
Sony vtc4/5 got 30A max discharge rate.
So to exceed that you would build a coil around 0.1-0.2 ohms which is crazy low.
For example im using 1 ohm coil in my kayfun. When the battery is fully charged (4.2v) it will drain 4.2 amps from the battery. ~ 17 watts.
If i build 0.2 ohm on a fully charged 4.2v it'll draw 21 amps (near safetly limit of 30a) and this would give a crazy 88 watts vape.
Fully charged battery holds 4.2v and goes down to around 3.9-3.7 and sits there for awhile. I usualy recharge around 3.6-3.7 due the vape isnt good enough anymore. (for me)
Edit: Nice baditude is in here.
(I linked to your blog posts in his other topic, which it seems he never read.)
Sony vtc4/5 got 30A max discharge rate.
So to exceed that you would build a coil around 0.1-0.2 ohms which is crazy low.
For example im using 1 ohm coil in my kayfun. When the battery is fully charged (4.2v) it will drain 4.2 amps from the battery. ~ 17 watts.
If i build 0.2 ohm on a fully charged 4.2v it'll draw 21 amps (near safetly limit of 30a) and this would give a crazy 88 watts vape.
Fully charged battery holds 4.2v and goes down to around 3.9-3.7 and sits there for awhile. I usualy recharge around 3.6-3.7 due the vape isnt good enough anymore. (for me)
Edit: Nice baditude is in here.
(I linked to your blog posts in his other topic, which it seems he never read.)
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I understand ohms law. Im confused about the 2600ma stated on the battery and the batteries amp limit. Also with the battery going from 4.2-3.7-3.2 if resistance stays the same then the current must be lower with the voltage drop.
Yes it will drop gradually, that's why mechs isnt for everyone.
2600mah is just a number to show how big charge the battery holds. The more Mah the longer the battery will hold.
If you look up the specs of the battery, you will want IMR cells and they're usualy specced "10a 2600mah imr"
Or sonys "30A 2000mah IMR"
The amperage is how much current you can draw from the battery and the higher amps the safer it is to build lower ohm coils.
And a good tip is not to stare at the higher mah rating, there's 3500+ mah batterys that are crap.
Sleezy is correct. If you are doing rebuildable coils (and especially sub-ohm coils), amps are far more important than mah as a battery specification.
Only use a 30 amp battery if building coils below 1.0 ohm. The lower the ohm, the more current the coil will pull from the battery. Always use a wide margin of safety head room when figuring coil ohms to use with the battery you are using -- better safe than sorry. Never use a battery if you don't know the amp limit of it.
1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
Cloud Chasing is Dangerous!
Only use a 30 amp battery if building coils below 1.0 ohm. The lower the ohm, the more current the coil will pull from the battery. Always use a wide margin of safety head room when figuring coil ohms to use with the battery you are using -- better safe than sorry. Never use a battery if you don't know the amp limit of it.
1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
Cloud Chasing is Dangerous!
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so V X R=I(amps). So we plug in 30A or 10A for I not 2600ma. How does the voltage drop effect the vapor production. How does the amp increase from increase ohms effect the production.
So you have a max of 30A. Your two variables are V and R to control this. Your resistance stays the same as your voltage drops. Whats a good ohm value for the coil.
Resistance depends on what you are looking for in vape quality, it is one of the variables you'll have to experiment with.
Some folks like hot vapor from a 1 or 2 second blast, others like cool vapor from a long slow pull.
Some folks like hot vapor from a 1 or 2 second blast, others like cool vapor from a long slow pull.
what Im saying is does more amps equal more vapor since its drawing more current. Are those ohm numbers using 4.2V for V
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