IMR, Protected or both?

[Skyblues]

I have been reading numerous posts on the advantages and disadvantages of various battery types. I have heard that it's either IMR (unprotected but safer chemistry) or protected.

I was about ready to buy some Panasonic IMR 18650s and ran into this ...
https://rtdvapor.com/online-store/batteries/cgr18650chbt-112-detail

It's a Panasonic Hybrid/IMR CGR18650CH Protected Button Top.
How can an IMR be protected? I thought that IMR and Protected were mutually exclusive.

Thanks,
Jim

 

[Faylool]

I'm curious too. I contacted rtd and asked them for explaination. Maybe you can do same.

 

[Rader2146]

Protection circuits are not needed for the IMRs or the Panny hybrids unless you are the kinda person that puts on a helmet, knee pads, and a reflective vest before going out to check the mail.

They are just catering to the uber-safety hysteria that surrounds lithium bats. The hysteria is mildly warranted, but the most dangerous thing about a lithium battery.....is the user.

 

[BuGlen]

Protection circuits are not needed for the IMRs or the Panny hybrids unless you are the kinda person that puts on a helmet, knee pads, and a reflective vest before going out to check the mail.

They are just catering to the uber-safety hysteria that surrounds lithium bats. The hysteria is mildly warranted, but the most dangerous thing about a lithium battery.....is the user.

@Rader2164 - What makes you think that battery safety is equivalent to hysteria? I'm not picking on you, but I do take issue with someone giving advice like this without even asking what the requirements are for the application of the batteries.

To the OP: The hybrid batteries by themselves are not what would be considered protected batteries, as they are just an even safer chemistry to the compared to some of the other current IMR batteries on the market. From what I understand, the hybrid batteries can still vent like the standard IMR batteries under the right conditions, but when they do, they do not get as hot. To me, that sounds like a good thing, even if the possibility of venting is rather slim.

Protected batteries are a different animal and have an additional protection circuit (wrapped into the top of the battery) that helps prevent certain possible battery failure conditions. The downside to protected batteries is that the protection circuit usually limits the amperage of the battery, so you might not be able to use them in high-draw devices, such as the Provari or VAMO. The upside is that if you have an unprotected device, such as a purely mechanical mod, then the protected battery adds additional safety features.

 

[Rader2146]

@Rader2164 - What makes you think that battery safety is equivalent to hysteria? I'm not picking on you, but I do take issue with someone giving advice like this without even asking what the requirements are for the application of the batteries.

To the OP: The hybrid batteries by themselves are not what would be considered protected batteries, as they are just an even safer chemistry to the compared to some of the other current IMR batteries on the market. From what I understand, the hybrid batteries can still vent like the standard IMR batteries under the right conditions, but when they do, they do not get as hot. To me, that sounds like a good thing, even if the possibility of venting is rather slim.

Protected batteries are a different animal and have an additional protection circuit (wrapped into the top of the battery) that helps prevent certain possible battery failure conditions. The downside to protected batteries is that the protection circuit usually limits the amperage of the battery, so you might not be able to use them in high-draw devices, such as the Provari or VAMO. The upside is that if you have an unprotected device, such as a purely mechanical mod, then the protected battery adds additional safety features.

I wasn't speaking of your normal everyday battery safety. Every battery and every device needs a certain degree of safety whether it be by safer chemistry or by electrical monitoring and disabling. I was speaking specifically about the uber (having the specified property to an extreme or excessive degree)-safety side of things, hence the [tongue-in-check] safety precautions for a seemingly mundane task like checking the mail.

I do understand your issues with me giving advice without any additional information about the application, but I didn't need any additional information. The application really doesn't matter unless he plans to use an atomizer with less than 0.5 ohms. It's pretty safe to assume that he will not be using that low of resistance. Using anything greater than 0.5 ohms the current drain from the battery is still under the maximum discharge current. This is based on a using a mechanical mod where high drain current is common. A VV device will fall on it face before the battery drain current gets anywhere close to 10 amps.

I'm not picking on your either, but there are a few things to correct.

hybrid batteries can still vent like the standard IMR batteries under the right conditions, but when they do, they do not get as hot.

Venting happens when there is thermal runaway inside the battery. What you really do not want is thermal runaway at a low temperature. Battery manufactures spend a lot of time trying to find ways to INCREASE the temperature at which thermal runaway happens. Increasing the thermal threshold means that it is more difficult, and thus less likely, to have a thermal event. Your typical Li-Cobalt (ICR) protected batteries have a lower thermal threshold than IMRs and the Panny CGR/CH.

The downside to protected batteries is that the protection circuit usually limits the amperage of the battery, so you might not be able to use them in high-draw devices

The protection circuit (on the bottom of the battery) is not the limiting factor for the amperage. The chemistry of the cell is the limiting factor. Lithium-Cobalt (LiCo) is more volatile than Lithium-Manganese (LiMn). LiCo simply cannot safely produce the current that LiMn can. When you do attempt to subject LiCo to more current that it can safely produce you get thermal events and catastrophic failures. This is fairly easy to do if you abuse the battery (again, the user is the most dangerous part of a battery). To combat this, the protection circuit is added and the over-current safety cutoff is set below the point of danger to protect the battery and the user.

LiMn and Hybrid cells do not need the added protection circuit because the probability of catastrophic failure (even when abused) is much less than LiCo, and when they (LiMn/Hybrid) do fail it is much less violent than LiCo (as in; no flames and no burning bits of battery guts).

 

[BuGlen]

I wasn't speaking of your normal everyday battery safety. Every battery and every device needs a certain degree of safety whether it be by safer chemistry or by electrical monitoring and disabling. I was speaking specifically about the uber (having the specified property to an extreme or excessive degree)-safety side of things, hence the [tongue-in-check] safety precautions for a seemingly mundane task like checking the mail.

I do understand your issues with me giving advice without any additional information about the application, but I didn't need any additional information. The application really doesn't matter unless he plans to use an atomizer with less than 0.5 ohms. It's pretty safe to assume that he will not be using that low of resistance. Using anything greater than 0.5 ohms the current drain from the battery is still under the maximum discharge current. This is based on a using a mechanical mod where high drain current is common. A VV device will fall on it face before the battery drain current gets anywhere close to 10 amps.

I'm not picking on your either, but there are a few things to correct.

Venting happens when there is thermal runaway inside the battery. What you really do not want is thermal runaway at a low temperature. Battery manufactures spend a lot of time trying to find ways to INCREASE the temperature at which thermal runaway happens. Increasing the thermal threshold means that it is more difficult, and thus less likely, to have a thermal event. Your typical Li-Cobalt (ICR) protected batteries have a lower thermal threshold than IMRs and the Panny CGR/CH.

The protection circuit (on the bottom of the battery) is not the limiting factor for the amperage. The chemistry of the cell is the limiting factor. Lithium-Cobalt (LiCo) is more volatile than Lithium-Manganese (LiMn). LiCo simply cannot safely produce the current that LiMn can. When you do attempt to subject LiCo to more current that it can safely produce you get thermal events and catastrophic failures. This is fairly easy to do if you abuse the battery (again, the user is the most dangerous part of a battery). To combat this, the protection circuit is added and the over-current safety cutoff is set below the point of danger to protect the battery and the user.

LiMn and Hybrid cells do not need the added protection circuit because the probability of catastrophic failure (even when abused) is much less than LiCo, and when they (LiMn/Hybrid) do fail it is much less violent than LiCo (as in; no flames and no burning bits of battery guts).

Thank you for taking the time to provide detail regarding battery technology and for correcting some of my points. I would also like to add that I fully agree with your assessment that an uneducated user of certain types of batteries is the most dangerous component in the equation, which is why I attempted to provide additional information. While my knowledge on the topic is limited, you apparently have either done your homework or you work in the field, so I very much appreciate your insight.

I would like to ask you if you have knowledge with regard to the type of damage that can be done to a IMR cell when it is over-discharged, which can easily happen in a purely mechanical APV. Does this (repeated) action simply decrease the overall lifespan of the battery, or can it result with the cell becoming unstable in a way which can lead to internal shorts and/or venting conditions?

Another thing I would like to ask with regard to unprotected cells is if you have a preference in a brand of charger? I tend to recommend the Pila for it's safety features and reputation, but it's not an affordable option for some people. If you have experience with other intelligent chargers that are more affordable, I would be interested as I'm sure others who read this thread might be as well.

 

[markfm]

Xtar wp2 ii.

Solid, good charge characteristic, comes with a 12vdc cig lighter adapter if you need to charge from car power.

Pick up an extra pair of spacers (about $1) if you use 16340 or 18350 batteries.

Set the switch to 0.5a for smaller batteries, 1a for big 18650 high capacity.

 

[BuGlen]

Xtar wp2 ii.

Solid, good charge characteristic, comes with a 12vdc cig lighter adapter if you need to charge from car power.

Pick up an extra pair of spacers (about $1) if you use 16340 or 18350 batteries.

Set the switch to 0.5a for smaller batteries, 1a for big 18650 high capacity.

Yes, I have that one as well. It's a good price for an intelligent charger with some good options (I especially liked the included car adapter). However, the one I have is now starting to exhibit a strange behavior where it will sometimes not register a battery in one of the 2 channels, and I've read of others having other quality issues with this model so I don't specifically recommend it any longer. It's a shame too, because it's quite affordable and has some really nice features.

Xtar has released what some vendors are touting as the successor to the WP2 which is the SP2, but that one is selling for $33 or more. For that price, I would just pay the extra $12 or so and get the Pila for it's quality and reputation. I have been reading that the select-able charge current @ 2 amps on the SP2 is good for quality IMR batteries to provide a shorter charge cycle, so that would be something to consider as well.

 

[markfm]

I also use a little Belkin timer, $10, set to 3 hours, that the chargers are plugged into. One button press to start the timer, power is positively cut off when the timer is done. The wp2 ii has a very low discharge rate when power is disconnected, you lose negligible time if the batteries sit in it, per the testing I've seen on the light forums.

 

[Rader2146]

Thank you for taking the time to provide detail regarding battery technology and for correcting some of my points. I would also like to add that I fully agree with your assessment that an uneducated user of certain types of batteries is the most dangerous component in the equation, which is why I attempted to provide additional information. While my knowledge on the topic is limited, you apparently have either done your homework or you work in the field, so I very much appreciate your insight.

I would like to ask you if you have knowledge with regard to the type of damage that can be done to a IMR cell when it is over-discharged, which can easily happen in a purely mechanical APV. Does this (repeated) action simply decrease the overall lifespan of the battery, or can it result with the cell becoming unstable in a way which can lead to internal shorts and/or venting conditions?

Another thing I would like to ask with regard to unprotected cells is if you have a preference in a brand of charger? I tend to recommend the Pila for it's safety features and reputation, but it's not an affordable option for some people. If you have experience with other intelligent chargers that are more affordable, I would be interested as I'm sure others who read this thread might be as well.

Repeated over discharge doesn't link directly to catastrophic failure, but it can in a round-about way. IMR's are good down to 2.5v, below that you are doing permanent damage to the cell. The damage shows it self in the form of increased internal resistance. Increased internal resistance means more energy wasted as heat output. More heat means increased chance of a thermal event.

The internal resistance of any battery increases with age and use. Over-discharging speeds up the aging process. If discharged too far a battery could be trash just by a single over discharge. If only a little, the battery could still have months of use left in it. Trash the battery if it ever goes below 1.5v. If the battery is above 1.5v, a good way to tell if it still has some life (without specialized equipment) is to attempt to charge the battery (on a smart charger). Make sure you have an identical, fully charged, known good, battery on standby to compare with. Using the lowest current setting, let the battery charge fully checking periodically for heat build up in the battery. If the battery get more than warm (compared to comfortable hand washing water temp) immediately unplug the charger and discard the battery when it cools. After it is fully charged remove the battery and measure the the voltages of the 2 batteries, let is sit and measure the voltage again in an hour. Repeat the measurements every couple hours until you have a warm and fuzzy on the health of the battery. A bad battery's voltage will drop from parasitic loss where a good battery will remain steady.

For chargers, I'm a big fan of the Xtars. I own 2 WP2 II and one SP2. The SP2 has many small refinements over the WP2 that I think make it worth the extra money. That doenst take anything away from the WP2 though, it is still an excellent charger. The SP2 has tighter tolerances when it comes to the CC/CV charging profile. They also improved the positive contact to be more friendly with flat top cells (I had trouble with certain flat tops not making contact on the WP2 and had to use a magnetic spacer). I keep the WP2's around for 18350's because the SP2 no longer has the threaded hole for the spacers that are supplied with the WP2 and that is easier than using magnets or a dummy plug on the SP2. Both chargers use a very low trickle current for bringing over-discharged cells safely back to life like I described above.