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Recharge a 3.7V Li-ion cell somewhere between 3.2 to 3.7V depending on the performance you expect from the system.
Thanks. On my other mods I was just using the protected batteries and used them until they shut off.
Uh... they should be 4.2 off the charger (2x4.2 = 8.4 so did you measure with them in series?) If so, that's 3.2 x 2 = 6.4 volts... but I'm not sure it truly works that way in series.... not sure they drain perfectly evenly.
Bottom line, unless you need high drain 18650 batteries, I recommend protected. Depends on the amp draw. On what type of device and using what atty/carto ohms? Did you put a regulator in it? What amp/watt regulator? It's all about the amp draw.
P.S. If a tube mod (all mechanical in particular but any), please make sure it is vented well or has a blow out plug pointing away from you. This is particularly true for stacked sets (in series):
Bottom line, unless you need high drain 18650 batteries, I recommend protected. Depends on the amp draw. On what type of device and using what atty/carto ohms? Did you put a regulator in it? What amp/watt regulator? It's all about the amp draw.
P.S. If a tube mod (all mechanical in particular but any), please make sure it is vented well or has a blow out plug pointing away from you. This is particularly true for stacked sets (in series):
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I built a dual 18650 mod with a madvapes VV regulator in it. I also put an lcd in it that tells me the battery(ies) voltage, and what volts I am sending to the carto. So as I said in the original post, off the charger, my lcd tells me my batteries are at 8.4 volts (2 in series) and it slowly goes down during the day. I just wasn't sure if at let's say it tells me 7.0 volts, I should pop them out and charge them? Odd thing was the first day I used it, it was slowly going from 8.4 down to around 7.0, then all of a sudden it dropped to about 5.5 or so. So I am thinking the 7.0v might be the magic number. It looks just like Mamu's denali mod (seen here on left) except I went with the MV regulator for ease.
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Cool mod. You should show it off in the modder's forum.
Yeah, I'm a little surprised by the exact voltage numbers on the sudden drop, but haven't measured my batts in series to see if it's similar. I'm sure you've seen or know the voltage curve for the Li-Ions.... they start at 4.2 and quickly drop to around 3.6/3.7 and stay around there for quite a while, then drop fast to cut off. Surprised it's that fast starting at 3.5x2 and dropping down to 5.5ish (2.8x2?) which is a normal PCB cut off for protected batteries (but many say don't even let them get that low). I'm wondering if one battery drops off faster than another (due to position) and thus would drain and drop faster to "low point".
The danger is letting them drop too low and then charging them, as I understand it. They can be ruined or worse.
Yeah, I'm a little surprised by the exact voltage numbers on the sudden drop, but haven't measured my batts in series to see if it's similar. I'm sure you've seen or know the voltage curve for the Li-Ions.... they start at 4.2 and quickly drop to around 3.6/3.7 and stay around there for quite a while, then drop fast to cut off. Surprised it's that fast starting at 3.5x2 and dropping down to 5.5ish (2.8x2?) which is a normal PCB cut off for protected batteries (but many say don't even let them get that low). I'm wondering if one battery drops off faster than another (due to position) and thus would drain and drop faster to "low point".
The danger is letting them drop too low and then charging them, as I understand it. They can be ruined or worse.
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Ya, I am on day 3 with it, so I don't have any real patterns yet. I will keep watching it to see how they work. The first day was when it dropped really fast. There is a *slight* chance I did something to cause it (not sure what) but the last couple days I have been charging them before they get that low. I think they are the panasonic versions of the "safe" AW IMR batteries. I have a few protected 18650's coming too.
Brew
Brew
I should note that I don't know any specifics for the Panasonics. I assume the low voltage is about the same. It's an assumption though. I'd try and find a spec sheet/data sheet on em.
This is where I picked them up.
Panasonic CGR18650CH 2250mAh - $7.99 : SmartVapes Electronic Cigarettes, Electronic Cigarette
Here is pdf for the batteries,
http://www.pohl-electronic.de/pdf/Panasonic/CGR18650CH.pdf
Panasonic CGR18650CH 2250mAh - $7.99 : SmartVapes Electronic Cigarettes, Electronic Cigarette
Here is pdf for the batteries,
http://www.pohl-electronic.de/pdf/Panasonic/CGR18650CH.pdf
I hear good things about them. Small discussion here with references to larger posts: http://www.e-cigarette-forum.com/fo...be-v1-5-3-2-amp-pretty-close.html#post6173024
Also, vid here:
Callies Kustoms IMR Battery and AW short circuit observations - YouTube
Also, vid here:
Callies Kustoms IMR Battery and AW short circuit observations - YouTube
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Batteries must drain equally, and should be always used as a pair. Its actually quite dangerous to have batteries at different voltage used together.
If you had them at 7V, that means each is 3,5V. Depending on the current drain from them, discharge curve at that point can indeed go downhill fast from there. You should probably take them to the charger at that point.
If you had them at 7V, that means each is 3,5V. Depending on the current drain from them, discharge curve at that point can indeed go downhill fast from there. You should probably take them to the charger at that point.
Nobody said they are used at different voltages. Yes, always keep them charged and use pairs.
His drop from 7v to 5.6 v was a matter of seconds (well, "All of a sudden") or a few vapes. That surprised me.. but the exact duration was not specified. I would have expected it to take longer at 7 volts...but drop more quickly around, for example, 6.8/6.6. However, after reviewing some charts, it looks like 7 (2 x 3.5) is about right for drop off.
His drop from 7v to 5.6 v was a matter of seconds (well, "All of a sudden") or a few vapes. That surprised me.. but the exact duration was not specified. I would have expected it to take longer at 7 volts...but drop more quickly around, for example, 6.8/6.6. However, after reviewing some charts, it looks like 7 (2 x 3.5) is about right for drop off.
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I was referring to this mostly:
That would be a dangerous situation, since they wouldn't be at the same voltage. One battery would probably reverse its polarity and try to charge the other one. I know he didnt said it actually happened, just pointing out a very dangerous situation that everyone who stacks should be aware of.
What exactly happened here; how "sudden" drop happened, I'm not sure. My best guess would be what I already wrote, that they simply reached the point on the discharge curve where they start dropping voltage quite fast. How "fast" would that drop be depends on the batteries and current being drained from them (or in other words, depends on the coil resistance being used). I'd probably stop using them at 7V (or even sooner), and toss them back on the charger.
That is not intended to say that one battery is at a drastically different voltage for long, rather, that the drop-off point may be triggered earlier on one (maybe) since one is slightly more positive than the other for a small amount of time (but they equalize themselves as they go). Thus triggering some cascade or something that caused the fast drop. They must equalize in series, but that can't be an instantaneous process (but maybe nano-seconds at normal loads).
In other words, I'm not saying that they are different voltages, but rather different poles and thus does one hit the curve slightly ahead of the other? However, it's moot anyway, since (see my post above) the dropoff is around 3.5v. I just thought it was slightly lower.
In other words, I'm not saying that they are different voltages, but rather different poles and thus does one hit the curve slightly ahead of the other? However, it's moot anyway, since (see my post above) the dropoff is around 3.5v. I just thought it was slightly lower.
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What happened when they dropped,
I was working (carpenter), went to the van to take a few drags, checked the batteries and they were around 7.0v +/-. Then I set it down on my seat and went back to work. about half an hour later I was at the van so I grabbed it and took another drag. Very little vapor, so I checked the batteries. It now said 5.5v.
I am not sure if it was from the heat in the van (probably 80 deg.F) or if I happened to set it upside down on the button, (I don't think that would fire it anyway, and I am sure the carto would have been fried if it did) or what. Like I said, it was the first day I used the mod and batteries, so could just be fluky. Hasn't happened since, so just might be a mystery.
I was working (carpenter), went to the van to take a few drags, checked the batteries and they were around 7.0v +/-. Then I set it down on my seat and went back to work. about half an hour later I was at the van so I grabbed it and took another drag. Very little vapor, so I checked the batteries. It now said 5.5v.
I am not sure if it was from the heat in the van (probably 80 deg.F) or if I happened to set it upside down on the button, (I don't think that would fire it anyway, and I am sure the carto would have been fried if it did) or what. Like I said, it was the first day I used the mod and batteries, so could just be fluky. Hasn't happened since, so just might be a mystery.
Lol. Interesting. Thanks for the info. Heat is a big factor in remaining life and usage curve from little I understand.
Also, since you built the mod, and know the circuit... you'd know if there was any (even minute) drain. Not uncommon, and often part of the circuit design (some mosfets for example are pulled-high for "off"). Also, just out of curiosity, does it have a cut-off switch? I try and get into the practice of switching my mod off when I set it down and walk away. Of course, being human, I sometimes forget or get interrupted (phone) or something and don't turn it off.
Since you are a modder, I'd add a cut-off switch if it doesn't have one.
Anyway, I think Malduk is correct... use 7v as a recharge point.
Hope you enjoy your nifty mod.
Also, since you built the mod, and know the circuit... you'd know if there was any (even minute) drain. Not uncommon, and often part of the circuit design (some mosfets for example are pulled-high for "off"). Also, just out of curiosity, does it have a cut-off switch? I try and get into the practice of switching my mod off when I set it down and walk away. Of course, being human, I sometimes forget or get interrupted (phone) or something and don't turn it off.
Since you are a modder, I'd add a cut-off switch if it doesn't have one.
Anyway, I think Malduk is correct... use 7v as a recharge point.
Hope you enjoy your nifty mod.
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