question on batteries

[ltrainer]

I've been using my set up since early January. Its been a Reo Grand and three Ultrafire 18650 3000mah batteries. I use LR 1.5 ohm 306s. I use the batteries in rotation and charge them up when they get down to about 3.8v. These batteries were the ones that were reccomended for the Grand at the tme of purchase of the Grand.

About a week ago I couldnt get a good vape. Holding the battery up to my ear the atty would fire then fizzle out after about a second. I guess the PCB is cutting off the battery. THen a few days later the second battery did the same thing, then a few days alter the last battery did it as well. They come off the charger at 4.18v all the time.

What causes this? I know its a safety feature. I figure any of these batteries has been through the equivalent of 100 full charges at most. Will draining them all the way down in some devise maybe reset the PCB in them? They havent been fully drained in months.

For the time being I am using atties in the 2 ohm range and its working. I don't care for the vape nearly as much though as I like a good hit that the 1.5 ohm gives me.

I ordered three new AW IMR 18650s and a new charger, the wf-139 though RTD. I'll be stalking the mail in a few days myself.

 

[ancient puffer]

I'm no battery expert, but as I understand it, here's the difference. The 3000 mah batteries are rated for .5C, which means if you draw more than their rated capacity, you're overstressing the batteries. (Battery university also has studies that show that will shorten the number of recharge cycles for the batteries).

The AW IMR 18650, otoh, is rated at 10C, so what I would expect is that you'll get a much better vape (since the battery can easily handle the current you're drawing), as well as much better battery longevity (number of recharge cycles).

The tech stuff (most of this comes from the 'net, and is as *I* understand it, so don't quote me): The C rating of a battery (or cell) is used to indicate the continuous current draw (amps) the cell will support. By multiplying the C rating times the cell capacity in mAh, the continuous current in milliamps (mA) of a cell is calculated as follows. For a 3000 mAh battery with a .5C rating, the continuous current that may be drawn out of the battery is 3000 mAh x .5 = 1500 mA, or 1.5 Amps (divide by 1000). The AW IMR would be 1600 mAh x 10 = 16000, or 16 Amps.

Using Ohm's law (I=V/R), the setup you're using (1.5 Ω) works out to a bit under 3 Amps (4.2v/1.5Ω), so using the LR is really stressing the 3000mAh batts (rated for 1.5 Amps), but would be a piece of cake for the AW IMRs (rated for 16 Amps..."high drain").

As noted, I'm no battery expert, so if the above calculations or info is incorrect, someone PLEASE correct me, but that's my uninformed take on it.

ETA: My understanding is LiOn's should never be completely drained, minimum on these is around 3.2v. And since they don't have a "memory" issue, you should always recharge as soon as their performance drops off. Many of us recharge when they drop to 3.9v

 

[mlinky]

Your atty is shorting the batts out. Don't use that atty.

 

[ltrainer]

Thanks for the reply. I think the batteries were just over stressed for the past 8 months or so and the batteries just are tired out and don't have the umpf anymore to power the atty. When I get the new AWs in I'll try it on those and see what happens. I' meter if first and go from there. Thanks.

Your atty is shorting the batts out. Don't use that atty.

 

[Skeeter T]

I'm no battery expert, but as I understand it, here's the difference. The 3000 mah batteries are rated for .5C, which means if you draw more than their rated capacity, you're overstressing the batteries. (Battery university also has studies that show that will shorten the number of recharge cycles for the batteries).

The AW IMR 18650, otoh, is rated at 10C, so what I would expect is that you'll get a much better vape (since the battery can easily handle the current you're drawing), as well as much better battery longevity (number of recharge cycles).

The tech stuff (most of this comes from the 'net, and is as *I* understand it, so don't quote me): The C rating of a battery (or cell) is used to indicate the continuous current draw (amps) the cell will support. By multiplying the C rating times the cell capacity in mAh, the continuous current in milliamps (mA) of a cell is calculated as follows. For a 3000 mAh battery with a .5C rating, the continuous current that may be drawn out of the battery is 3000 mAh x .5 = 1500 mA, or 1.5 Amps (divide by 1000). The AW IMR would be 1600 mAh x 10 = 16000, or 16 Amps.

Using Ohm's law (I=V/R), the setup you're using (1.5 Ω) works out to a bit under 3 Amps (4.2v/1.5Ω), so using the LR is really stressing the 3000mAh batts (rated for 1.5 Amps), but would be a piece of cake for the AW IMRs (rated for 16 Amps..."high drain").

As noted, I'm no battery expert, so if the above calculations or info is incorrect, someone PLEASE correct me, but that's my uninformed take on it.

ETA: My understanding is LiOn's should never be completely drained, minimum on these is around 3.2v. And since they don't have a "memory" issue, you should always recharge as soon as their performance drops off. Many of us recharge when they drop to 3.9v

AP, Ya done good. Excellent explanation that directly answers the problem. There'll be a little extra in your pay . So, a batt can be "over-stressed" (pulling more amps than its C rating) and the C rating then must be a max safe load that will extend batts to their rated life (recharge cycles). I didn't know that. I thought the C rating was a max current the batt could put out. Very interesting. Now it really makes a lot of sense why the IMR's are the recommended batts especially with LR atty's. I'm becoming a big AP fan.

Ted

 

[ltrainer]

Thanks ancient puffer. I replied to your post earlier but apparently I hit a wrong button or ECF screwed up somehow. Anyway I wrote that I was under the impression that the ULTRAFIRE 18650 3000 had a C rating of 1.5. This info was on ECF for a while and I was going under that information. Upon seeing the C rating that you gave of .5 I looked it up and that's what I found. You are correct and that explains what has happened to my batteries. Over the 8 months that I have been over stressing them they have built up an internal resistance(cholesterol). They no longer have enough power in them to power y 1.5 ohm atties. Their life have been greatly shortened. RIP batteries. Thank you for the information. I am now stalking the mail person as I hate digging out old higher ohm cartos and attys since I like a much hotter vape.

I'm no battery expert, but as I understand it, here's the difference. The 3000 mah batteries are rated for .5C, which means if you draw more than their rated capacity, you're overstressing the batteries. (Battery university also has studies that show that will shorten the number of recharge cycles for the batteries).

The AW IMR 18650, otoh, is rated at 10C, so what I would expect is that you'll get a much better vape (since the battery can easily handle the current you're drawing), as well as much better battery longevity (number of recharge cycles).

The tech stuff (most of this comes from the 'net, and is as *I* understand it, so don't quote me): The C rating of a battery (or cell) is used to indicate the continuous current draw (amps) the cell will support. By multiplying the C rating times the cell capacity in mAh, the continuous current in milliamps (mA) of a cell is calculated as follows. For a 3000 mAh battery with a .5C rating, the continuous current that may be drawn out of the battery is 3000 mAh x .5 = 1500 mA, or 1.5 Amps (divide by 1000). The AW IMR would be 1600 mAh x 10 = 16000, or 16 Amps.

Using Ohm's law (I=V/R), the setup you're using (1.5 Ω) works out to a bit under 3 Amps (4.2v/1.5Ω), so using the LR is really stressing the 3000mAh batts (rated for 1.5 Amps), but would be a piece of cake for the AW IMRs (rated for 16 Amps..."high drain").

As noted, I'm no battery expert, so if the above calculations or info is incorrect, someone PLEASE correct me, but that's my uninformed take on it.

ETA: My understanding is LiOn's should never be completely drained, minimum on these is around 3.2v. And since they don't have a "memory" issue, you should always recharge as soon as their performance drops off. Many of us recharge when they drop to 3.9v

 

[ancient puffer]

ltrainer,

I wasn't sure what the C rating for them was either, so I googled it

I suspect that you'll see a difference with the IMR's, even with a higher ohm rating, but they will handle the 1.5 LR's just fine. I have a tendency to stay around 2.0Ω, mostly because it works well with all my juices, the lower resistance ones are good with *some* juices, but, especially in the case of the sweeter fruity ones, they can be too hot and you lose the flavor.