How to determine/calculate maximum discharge rate for battery?

[NatureBoy]

Anyone know the formula for determining what the maximum discharge rate for a battery?

I'm looking at some 14250 IMR batteries that are only rated for 300mah, but I need to know if they can handle a coil built at around 1.6-1.8 ohms, but I don't know how to calculate that.

The manufacturer told me it's 600mah, but that seems really low. I'm using 18350 IMR batteries that are 700 mah, what would their max discharge rate be? I'm I stressing that battery by using it with a 1.6ohm coil?

 

[KenD]

As far as I know there's no way to calculate the maximum discharge rate. You need to find the spec sheets for the particular batteries you have.

Sent from my GT-I9100 using Tapatalk

 

[Baditude]

You'll need to know the C Rating of the battery. You'd get this from the battery's specifications (if provided). This info may be difficult to find with such a rare size battery. What's In a C Rating?

600 mAh for a 14250 battery does not sound awfully low. This is an extremely tiny battery. An 18350 IMR 700 mAh will have an amp rating of around 6 amps continuous discharge rate.

Battery Amp Limit Calculator

Battery Basics for Mods

 

[Vwls]

Make it easy on yourself - use this info:

AW IMR
18650 2000mah 10A (5C)
18650 1600mah 24A (15C)
14500 600mah 4.0A (6.7C)
18490 1100mah 16.5A (15C)
18350 700mah 6A (8.6C)

Sony
us18650v3 IMR 2250mAh 10A (4.4C)
SE US18650VTC3 1600mAh 30A (18.75C)

Samsung
INR18650-20R 2000mah 20A (10C)

MNKE
IMR18650 1500mah 20A (13.3C)

Orbtronic
Ultra High Drain 18650 SX30 Rechargeable Hybrid Li-ion 30A

Panasonic
CGR18650CH 2250mAh 10A (4.4C)
NCR18650PD 2900mAh 10A (3.4C)

EH IMR
18650 2000 mAh 16A (8C)
18500 1100 mAh 8.8A (8C)
18350 800 mAh 6.4A (8C)
14500 600mah 4.8A (8C)

EFEST IMR
18650 2000mah 10A (5C)
18500 1100mah 8.8A (8C)
18350 800mah 6.4A (8C)
14650 950mah 9.5A (10C)
14500 700mah A (C) (No information found on this one)

Higher mAh will mean longer time of use before requiring charging.

Higher C rating means more amps in reserve for high drain applications.

C rating = the maximum sustained (not burst) output of a battery. Calculating it requires knowing the mah rating of the battery and its value.

Do battery safety calculations at 4.2V (a fully charged battery), not 3.7V (a depleted battery).

The DNA 20 chip will output 7 amps and 20 watts. The Cyborg is one example of a pv that uses this chip.

2800mah, 2C= 5.6 amps
3100mah, 2C= 6.2 amps

Kanthal A-1 Wire Specs: (Ohms Per Inch)
•28 AWG- 0.439 Ohms/in, 0.0508 Diameter (in.)
•30 AWG- 0.696 Ohms/in, 0.0100 Diameter (in.)
•32 AWG- 1.091 Ohms/in, 0.0080 Diameter (in.)
•33 AWG- 1.383 Ohms/in, 0.0071 Diameter (in.)
•34 AWG- 1.758 Ohms/in, 0.0063 Diameter (in.)

Sub-Ohm Vaping Vids:
http://www.youtube.com/watch?v=hWrosk_xjkY\
Resistance & Air Flow - YouTube
Batteries, Volts, Amps and You - YouTube

1.2 mm ID = 3/64 drill bit

Calculate Coil Resistance & Battery Life
PV Web Apps


AW Batteries

AW is actually the initials of Andrew Wan. He owns a company based in China that has been selling batteries to hobbyists since 2005.

When a company manufactures batteries, they “bin” the batteries by quality. Andy purchases top bin batteries from premium manufacturers. He then takes those batteries and puts them through his own testing. If they pass his strict testing, he wraps them with his logo.

For instance, AW’s line of LiNiCoO2 cells use Panasonic batteries. The protection circuit he uses in some of his batteries is his custom design and build (and many consider it the best available). He was also instrumental in bringing IMR batteries to the hobbyist market and popularizing them there.

Note: the battery shipping situation has made buying directly from AW impractical for many, as direct shipments of batteries from him take a couple of months to arrive via surface mail. Due to the popularity of his batteries, there are many counterfeits. Be careful where you buy, and avoid eBay.

Lighthound.com, RTDVapor.com, Oveready.com, KindeyPuncher.com, Vaporkings.com, foursevens.com, eliteled.com, 18650flashlights.com, & Nitemods.com all sell genuine AWs.

 

[yo han]

I'm looking at some 14250 IMR batteries that are only rated for 300mah, but I need to know if they can handle a coil built at around 1.6-1.8 ohms, but I don't know how to calculate that.

14250 is a very small battery. Let's assume your IMR has a 7C rating (only the spec sheet can tell you this) and so can handle 2.1A (7x 300mA). Say you're using a 1.8 Ohm coil and want to vape 7 Watts. This means using 3.5 V and your device is pulling 2A (2000 mA).
300mAh divided by 2000mA is 0.15 hours which equals 9 minutes. And that's a very positive figure because capacity ratings are measured from fully charged 4.2V to 3.0V. Most devices cut off at 3.2V. Let's say it can do 7 minutes at reasonable power and your average drag is 7 seconds. 420 seconds (7 minutes) divided by 7 seconds equals 60 drags. That's not a lot so be prepared to take lots of batteries with you.

 

[NatureBoy]

lol, thanks for the replies. I'm still getting it because of how rare and cool it is )), but at least now I'll know not to expect it to vape for very long. It's more of a super stealthy mod for rare occasions where I might want/need something really small.

Good info posted in here though!

 

[yo han]

Now you've made me curious. Can you post a link to the device please?

 

[NatureBoy]

It's the JM16 Mini. Someone has one posted in the classifieds. I got excited when I saw it, but couldn't afford the steep price tag, so I contacted JM and asked if he'd be making anymore in the future. He got back to me and said he had one for sale (then 4 more went up on the store), 43 euro shipped.

 

[yo han]

Ah it's cute!
I can understand you want it because it looks great.
However, because it's so underpowered I'd consider it as a novelty item rather than a serious product.
Oh by the way, I've been looking into the discharge rating subject and if it's not IMR you should take the 2C discharge rate as a rule of thumb. However, this is for safe constant discharge. Since e-cigs only have to handle few second bursts now and then (you're not going to chain vape with this mini ) you can safely use 3C. Still, that means only 3.3Watts of power max.

 

[NatureBoy]

I have found some Efest 14250 IMR batteries that I'm going to order. Likely 4 of them...

 

[NatureBoy]

Scratch that. Efest refused to ship to the US. Cancelled my order for the mini, got a refund. No point getting the thing if I can't get batteries for it. JM recommended regular, unprotected li-ion batteries.. as if.

Back to the OT, is there a way to figure out what load an atomizer is placing on a battery? If a coil is 1.8ohm, how much current is it drawing? I should know this considering I went to school for EE, but I didn't do so well.. lol

Is it just plain ol ohms law here? I=V/R?

 

[Kemosabe]

It's the JM16 Mini. Someone has one posted in the classifieds. I got excited when I saw it, but couldn't afford the steep price tag, so I contacted JM and asked if he'd be making anymore in the future. He got back to me and said he had one for sale (then 4 more went up on the store), 43 euro shipped.

is this it? if so, looks super stealthy!

heres an AW unprotected 14250. i almost bought them for my VMod 2.0 but decided against it. it doesnt appear to be IMR. i bet the eFest ones are better if they are indeed IMR chemistry.
AW 14250 Unprotected Rechargeable Lithium Battery

 

[Baditude]

Back to the OT, is there a way to figure out what load an atomizer is placing on a battery? If a coil is 1.8ohm, how much current is it drawing? I should know this considering I went to school for EE, but I didn't do so well.. lol

Is it just plain ol ohms law here? I=V/R?

Basically, yes it is. Here's a calculator to make it easier: OHM'S LAW CALCULATOR

Always use 4.2 volts (fully charged battery) for the voltage. Add the resistance (1.8 ohm) into the calculator. Click calculate. The current shown will be the amps drawn from the battery.

 

[NatureBoy]

Thanks, that's nice and easy to use.

 

[yo han]

Great, keep us posted on how it's going. And be careful not to drain them too far.