Battery question

[AttyPops]

Sorry for the "intrusion" but I need to ask the brain trust, so I knew right away what part of the forum to go to....

I know about "Battery University". I have the link. Don't bother posting it.

But, the question is:

It there a summary (Chart or spreadsheet?) for max drain on batteries by standard type? Something like

Chemistry	Size	Max Amp Drain	Max Amp Drain (2 stacked)
IMR	14500	???	????
IMR	18650	???	????
Li-Ion - protected	14500	???	????
Li-Ion - protected	18650	???	????

Or does it vary too much by manufacturer, specific chemistry, etc? This all comes from a question posted here:
http://www.e-cigarette-forum.com/fo...od-battery-question-smartvapes-altoid-vv.html
Why is an Altoids mod sold with two unprotected IMR 18650's? (And should we care?) The guy is thinking he should only order IMRs. OK. But why? No mention in that post of amp limits on the regulator or device.

How does it work with stacking?
Is it even possible to create a "safe" version of this chart (conservative version would be a better term, I guess).

I'd love to see this as a stickey someplace. Maybe not possible/practical. IDK.

EDIT: This is posted in this area, since I'm not talking about "Battery Mods" but rather "batteries for mods". Also will get more views in the general modding area.

 

[Java_Az]

The simple answer is no there is no standard chart for this because they are not all made the same you have different brands and even different brands make different capacity models for the same size. Li ions are usually capacity x2 for max amps so a 2100mah 18650 li ion would be 4.2 amps a 3100mah li ion would be 6.2 max amps. Capacity x2 is also not set in stone But it is pretty safe to use on Quality made Li ion's. IMR's can very by manufacture so really the best way with any battery is to find the data sheet for that battery and go by it. Putting two batteries in series does not increase the max amps or the mAh rating , they stay the same. What doubles is the voltage and wattage.

 

[AttyPops]

Thanks. Yeah, I was afraid of that Java. Even worse that it's so specific to make/model.

I almost deleted that right hand column, but meh. Didn't know if it had a positive (or even a negative) effect.

So a general rule (with possible extreme exceptions):
1) Double battery (in series) mods usually don't need high-drain (at least as of this date)
2) as long as it's a quality battery and amps won't exceed 2x mAh of one battery.

Now, I know that the protection circuit trips on standard protected batteries but would not trip on IMRs in some cases. Hence IMR. So does the rule differ for each? In other words, is the 2x mAh for protected or non-protected IMR types?

 

[Java_Az]

As far as i know there is no one making protected IMR batteries. Supposedly if they go terminal they just ooze their insides out instead of venting 2000 degree gasses like a li ion. AW IMR 18650's 1600 mah have a max amp drain of 16 amps so they are 10 x capacity. The Panasonic hi drains 2100mah 18650 that are fairly new have a 10 amp max drain. technically the new Panasonic's are not true IMR but they are supposedly safe chemistry and folks have been advertising them as IMR's. I would go by the spec sheet for IMR's i have seen there ratings all over the place.

 

[AttyPops]

Yeah and I knew that too...IMR not protected (just worded the whole thing badly, see chart in post 1). I was really trying to say something like "The protection circuit on Li-Ion batteries can trip on high amp draws where a high-drain IMR will handle a reasonably high amp load. Hence high-drain IMR."

So I meant that the 2x calc must be for protected Li-Ion batteries, not IMR batteries... True? And you answered yes. I should have realized that when you say "li-Ion" you mean protected, and when you say IMR you mean IMR. And of course we don't recommend unprotected Li-Ion anyway, so they are not even in the chart.

So I just wanted to make sure that the 2x calc was for the protected [Li-Ion] batteries and not the non-protected IMRs, and it's obviously for the Li-Ion. I'm going to use the 2x single mAh rule as my rule of thumb for decent quality protected Li-Ion cells. For IMRs... check the spec sheet.

Thanks again Java.

technically the new Panasonic's are not true IMR but they are supposedly safe chemistry and folks have been advertising them as IMR's.

Hmmm. Interesting. Yeah, definately check the spec sheet!

The good news is that he (link in post#1) is using an Altoids box, so it would "only" blow the top off if it ever vented (Li-Ion ..unprotected). IDK why he's using it with high-drain stuff tho. No need with 2 18650's that I can think of. Even a DCC should work (3.125 amps for 1.6 ohms at 5v) I would think. Particularly if we use the 2x mAh rule for a decent protected 18650.

The quote he had is what got me thinking about unprotected batteries and shorts/high-loads. But if they just ooze gunk, may not be an issue. It is a metal box tho. But the top flies off, and it shouldn't "go boom". IDK if there's a shock risk. Hmmmmmm.

 

[Str8V8ping]

AW IMR's dont really need protection since they are a safer chemistry batteries. Iv taken them down to 2.2v plenty of times before and they have never vented or got hot on me. When they drain that far just letting them sit they automatically bounce back up to 2.5v without even putting them on a charger . Not saying its not possible for them to vent but they can handle a lot more then a regular Li-ion. Even with Li-ions protection circuits have been known to fail.I personally would take a IMR over protected li-ion anyday.

 

[AttyPops]

Thanks Str8. Good to know.

However, the quote (from the link in post 1) was referring to a charged battery and a dead short. Thus, it said to only use protected batts in mods unless the mod had some additional protection in the circuitry. I thought it was interesting.

 

[Str8V8ping]

Theres no reason you cant use a protected battery in it if you wanted. Are you sure theres no protection built into the chip?

Heres a cool video showing direct shorts on AW IMR's and Panasonic IMR's
Callies Kustoms IMR Battery and AW short circuit observations - YouTube

 

[AttyPops]

Theres no reason you cant use a protected battery in it if you wanted. Are you sure theres no protection built into the chip?

Heres a cool video showing direct shorts on AW IMR's and Panasonic IMR's
Callies Kustoms IMR Battery and AW short circuit observations - YouTube

Not sure at all with that mod since I don't know the circuit. However, it is reasonable to assume that since it has circuitry and is a vv mod the regulator has some form of overload/trip feature. That would protect against a short at the atty connector at least. Like anything else, it depends on where the short is I guess.

Cool vid.

Looks like the Panasonic doesn't discharge as fast (actual rate, not the amp rating). As long as it's a 10 amp limit, that's OK with me. I'd still use them in a buck/boost mod or something even with DCCs. 10 amps is plenty IMO.

Also good to see that neither battery flamed out (although the AW had a small ...?hole? or "spot").

 

[Str8V8ping]

It most likely does have a reverse polarit/themal shutdown in the chip but your right that they should put extra protection in there anyway since its not hard to add. I always use a PTC fuse and low voltage cutoff on top of the build in chip protection on my mods. For a high power vv mod though IMR's are the best choice and batteries are cheaper then the AW protected.