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  1. Here are the links to each of my blog entries. This index will be updated as new entries are added.

    Links to All My Tests and My Recommended Batteries

    Test Results, Ratings, and Performance Tables

    General News

    Assorted Battery Stuff

    My Background, Equipment and Testing Methods
    Phil Lee, Theis, Capt Donna and 17 others like this.
  2. Here are the ratings for the 20mm and 21mm diameter batteries:


    Click on the thumbnail above to download the full size table
  3. I'm often asked how fast a particular battery can be charged. Here's my answer. :)


    Click on the thumbnail above to open the full-size table
  4. It's widely believed that the LiPo battery packs used in DNA200/250 and custom box mods need to be charged/discharged several times before they reach their peak performance.

    Is this true?

    To find out I took three new 3S packs and balanced charged them at 5A on an iCharger106B+ to 12.60V followed by a discharge to 9.0V at 20A constant-current. I did this a total of five times for each pack with a 60 second rest between each step. A lot of effort was made to ensure that the pack temperatures were consistent from cycle to cycle.

    Here are the three discharge graphs:
    IMG_4846.jpg IMG_4847.jpg IMG_4848.jpg

    As you can see there was no increase in the capacity of the pack or an increase in its voltage while being discharged (which would indicate a decrease in its internal resistance).

    For two of the three packs I measured the internal resistance before and after the tests were done:

    Turnigy 25C-35C 2200mAh before = 18.3 mOhms
    Turnigy 25C-35C 2200mAh after = 18.5 mOhms

    MaxAmps 100C 2250mAh before = 21.9 mOhms
    MaxAmps 100C 2250mAh after = 22.8 mOhms

    The break-in cycles didn't lower the internal resistance of the packs. In fact, they did exactly what any use of the pack does...ages the pack and increases its internal resistance.

    The break-in cycling did not improve the performance of any of the three packs. It only wasted five of the limited number of cycles available before the packs would need to be replaced.

    I also did five break-in cycles for each of the ten 1800mAh 3S LiPo packs I recently tested. Those break in cycles were done at some pack assembler's typical recommended levels, 1C charge and 2C-3C discharge. There was no increase in performance between cycle 1 and cycle 5 for any of the packs.

    Will this be the case for every LiPo? I don't know.

    There might be some LiPo's that were not fully formed (initialized) at the factory in order to save money. Their performance would increase during the first few cycles. There also might be some that were stored for a long time before being used. This can cause the thickening of an important chemical divider (the SEI layer) between certain parts of the battery, increasing its internal resistance. Cycling the battery can reduce its thickness and restore some performance.

    I know that many in the R/C community feel strongly that this cycling is needed but the tests described above and my recent testing of ten different 1800mAh 3S LiPo packs showed no increase in performance after being cycled a few times.

    I have an idea why some might feel they are seeing an improvement in performance though.

    LiPo cells, which use lithium-cobalt chemistry, show a very small change in voltage for a big change in capacity during most of the discharge compared to other Li-Ion chemistries. This "flat discharge curve" is one of the big benefits of using LiPo's.

    But this flat discharge curve also means that just a small change in the voltage of the battery can result in a big change in the capacity the battery delivers to cutoff voltages above 3.2V or so. If the pack is warm its internal resistance drops and the voltage the pack runs at is higher. This allows the pack to run for a lot longer before dropping to the cutoff voltage.

    Since the outer wraps of a LiPo pack are very effective heat insulators the internal temperature of a LiPo pack can be a lot higher than the external temperature. It can seem to be only a bit above room temperature but actually be much warmer. Unless the pack is allowed to sit for at least an hour after charging, two hours or longer for larger packs, the internal resistance could be lower than when the pack was first used in the tests.

    This would cause the packs to run at a higher voltage, making it seem that its performance had improved with cycling. But the improved performance was really only due to the pack being warm.

    I am not saying that everyone who cycles their packs and says they see an improvement is wrong!

    I am not saying that no LiPo packs respond to break-in cycling!

    I am merely saying that in my testing of thirteen different packs I see no sign of break-in cycling having any effect on performance. It shouldn't though. Properly formed packs, not stored for months and months, should not need any sort of break-in to reach their best performance levels.

    I'd be interested in hearing your experiences regarding breaking in LiPo packs, especially if you took measures to make sure internal pack temperatures were consistent for each cycle.

    VanessaU, Ariel_MX and mikepetro like this.
  5. How I am setting LiPo ratings

    I am about to start posting the 1800mAh LiPo pack test results so I wanted to review what the ratings mean in the new 1800mAh LiPo ratings table that will be posted soon.

    You can go over any of these ratings while vaping!
    The ratings are not limits. They are used for directly comparing the performance of one pack against another, seeing which pack assemblers are bull....ting us, and for setting reasonable safety margins while vaping. Using these ratings can help you decide which pack to use and how hard you want to use it.

    I don't care what battery you use or how hard you use it. Just so long as you know its true ratings. :)

    The 1800mAh packs I am testing this time around are the only ones that will be tested for a few months. I have a huge backlog of 18650's to test and then the 2200mAh and 3000mAh LiPo's before I can even consider testing additional 1800mAh packs. Hopefully this round of testing will give everyone an idea of what packs might be good to use in their mods.

    There are several concerns when using LiPo packs....

    They use the most volatile of the Li-Ion chemistries, going into thermal runaway and bursting with flames at the lowest battery temperature and the most violently. Keeping LiPo packs in perfect physical condition and not short-circuiting them is critical.

    They are damaged at much lower temperatures than the round batteries we use. Most LiPo's are badly stressed at about 60°C and permanently damaged by 80°C. The round batteries we use are rated to be run at about 80°C and typically aren't badly damaged until they reach over 110°C.

    This means that we need to think differently about judging whether we are running a LiPo pack too hard. Accelerated aging occurs when the outside of a LiPo pack is just a bit warm and the recommended temperature limit is reached by the time a pack is around what most would call very warm.

    Puffing up of the silver "pouch" of a LiPo cell indicates that it is being severely stressed. If the puffing goes away when the pack cools then it probably wasn't badly damaged. If the puffing remains after it has cooled then the pack is damaged and should not be used again. Tape up the connections to prevent a short circuit and recycle the pack.

    C ratings are useless. Some packs exaggerate them beyond comprehension with some actually rated above the point where 12AWG wire would melt. Melt! Even if we call that a "pulse" rating the wiring would reach several hundred degrees.

    If we need to multiply the capacity by the C rating to get the current rating then why not just include the current rating on the wrap and drop the C rating? It is promoted as a way to compare packs but that means it is the first thing that gets manipulated to entice us to buy a pack. Be wary when buying a pack based on its C rating.

    Some would argue that just a single C rating on the wrap means it's a pulse rating. But how long a pulse? How much time between pulses do we need to have? What criteria were used to set the rating (run time? temperature? voltage sag?)? Without this information for each pack a "pulse" rating is useless as we can't compare any packs using it.

    Here are the ratings I am using for LiPo's...

    CDR = Continuous Discharge Rating. The nearest 5A-multiple of constant-current continuous discharge current that brings the inner cell of a 3S pack to a temperature of 60°C. This is what the LiPo assemblers recommend as the max running temperature so it makes sense to use it as the rating. Especially since the inner cell will be hotter internally than this temperature, perhaps considerably.

    Testing shows that the temperature of the middle cell in a 3S pack is 7°C-10°C higher than the temperature of the outer cells (but still under the shrink wrap and protection wrap). This means that when I measure a temperature of about 50°C-53°C the inner cell of a pack has reached at least 60°C, its limit. A 2S pack will run a bit cooler and a 4S, or higher, pack will run a bit hotter than this.

    Most of the 3S packs I have start puffing (temporarily) at around 60°C or lower so I agree with the pack assemblers that it should be used as the max running temperature for decent cycle life. Going over this temperature will start damaging the pack a lot faster. Note that at an internal temperature of 60°C the outside of a pack is just warm.

    The protective and shrink wraps used on these packs are very effective insulators. It takes at least an hour for each pack to cool back down to room temperature internally. These 1800mAh packs are small too. Larger packs would take at least a couple of hours to cool.

    MVA = Maximum Vaping Amps rating. To help prevent overheating during chain vaping and for a safety margin in case of mod malfunction, don't exceed the MVA rating. It helps to limit the pack temperature to 60°C or lower.

    MaxSafe = Maximum Safety Amps rating. To help prevent the possibility of venting or thermal runaway in case of a mod malfunction or accidental button press never go over the MaxSafe rating. It helps to limit the pack temperature to 80°C or lower. The pack can still be damaged, perhaps permanently, at this temperature though.

    The minimum temperature at which a LiPo pack will go into thermal runaway is considerably above 80°C but the temperature of a pack in a mod can be a lot higher than seen during my testing. Older cells (which run hotter), being inside a warm mod, operating near a hot circuit board and/or atomizer, or vaping on a hot day can all bring the temperature of a pack considerably higher.

    I want to state again that these ratings are not hard limits. They're just for directly comparing the performance of different packs and for figuring out how hard we want to use them.


    Click on the thumbnail above to download the 1800mAh 3S LiPo pack ratings table
  6. This blog entry will list all items I purchased with the incredible donations the vaping community made to help me buy batteries for testing and to build a dedicated vaping battery test area.

    Total Remaining = TBD

    Equipment Fund Withdrawals:
    • GoFundMe fees = TBD
    • Federal, State, and Local taxes = TBD (GoFundMe states they send out a 1099 in some circumstances. I'll get more info about this but all the purchases are deductible so there probably won't be any donations held aside for taxes).
    • 9/27/16 — $44 — Two high pressure replacement fans for the electronic loads.
    • 10/5/16 — $489 — iCharger 4010 Duo charger, PowerLog 6S meter, connecters, and cable for high power battery cycle life testing and marrying/rotating testing.
    • 10/5/16 — $489 — Three 30V/5A adjustable and one 30V/24A adjustable power supplies to replace the five supplies that were trashed by an electrical surge.
    • 10/6/16 — $264 — Datalogging thermocouple thermometer to replace failing unit.
    • 10/8/16 — $65 — Ten port USB hub (3 for charge, 7 for USB devices).
    • 10/13/16 — $58 — Five laptop power bricks and power cords to power the chargers.
    • 10/14/16 — $TBD — Tektronix TBS2102 oscilloscope for PWM mod and charger battery testing.
    Battery Fund Withdrawals:
    • GoFundMe fees = TBD
    • Federal, State, and Local taxes = TBD (GoFundMe states they send out a 1099 in some circumstances. I'll get more info about this but all the purchases are deductible so there probably won't be any donations held aside for taxes).
    • 9/27/16 — $30— Two AWT 50A cells.
    • 9/27/16 — TBD — Three sets of MXJO batteries.
    • 9/28/16 — $108 — Twelve high capacity Samsung/Panasonic/LG batteries, 26650 boxes, ring insulators.
    • 10/7/16 — $60 — Eight additional high capacity batteries.
    • 10/7/16 — $34 — Two HB7's and Two 3500mAh MXJO 26650's.
    • 10/13/16 — $75 — Fourteen Kdest battery samples.
    My contributions of equipment for the vaping battery test setup:
    • Fluke 87 handheld meter
    • Fluke 8846A desktop meter
    • iCharger 106b charger (for married-battery cycling)
    • Three 0-30V/0-5A power supplies (for charging and powering other chargers)
    • Two LUC V4 chargers.
    • West Mountain Radio CBA IV Pro battery analyzer w/extended software license.
    • Three CamLight Systems CC-400 400W/150A electronic loads (for increasing the battery analyzer's power handling).
    • Waye Giles ESR Meter (for measuring battery internal resistance).
    • Two Acer netbooks for running the battery analyzer and recording data from the other devices.
  7. It's time to put this myth to rest. Using rice to help dry batteries or a mod that got wet doesn't help at all. In fact, it slows down evaporation of any water that is inside.

    I set up a 24 hour test using paper towel sheets with enough water added to bring their weight to 18 gms. I then put these wet folded paper towels in four places; a slightly ventilated box in rice, a slightly ventilated box 3 feet in front of a fan on low, a bare folded paper towel in still air, and a bare folded paper towel 3 feet in front of a fan on low. The complete results are in the table but two are presented here...
    • Amount of water that evaporated from the box in the rice after 24 hours = 2 gms
    • Amount of water that evaporated from the box in front of the fan after 24 hours = 10 gms
    Five times more water evaporated from the box that was in front of the fan. It's clear that burying anything in rice just slows down the evaporation of any water that's present. This makes sense though. Rice can't vacuum up water. It can only absorb any water that evaporates and touches the surface of the rice. Even then though rice is a lousy absorber of atmospheric water.

    Since the device that is wet is buried in rice, with no air movement, the humidity level quicky rises up to 100% next to any water that is present inside the device. This significantly slows down any evaporation that could take place.

    Adding air movement blows away the layer of very humid air above any water, allowing the water to evaporate much faster.

    Some of you might have tried using rice and found that you could turn on your mod a day or two later and it worked. But did you open up your mod to see if the water had actually evaporated? How can we know that the rice did anything?

    Bottom Line: If you have a mod that got wet, do not turn it on. Remove the batteries (if possible), shake out any water you can, and then place it in front of a fan. Rotate it every couple of hours to try to get any blowing air into any seams or ventilation holes. It should be pretty dry internally in 24 hours.

    Please don't bury it in rice!

    [edit] I'm sure there will be those who feel this test was invalid for one reason or another. It's backed up by every good test like this I found online but I strongly encourage anyone who feels I erred to do their own tests. I would love to see the results!

    [edit] For those who are concerned that the paper towels "lock in" the water, keeping it from evaporating:

    Pictures of the setups:

    Attached Files:

  8. Some chargers, like the Efest LUC V4, can be used to charge batteries that have dropped to very low voltages, below 2.5V. While this is tempting there is a risk when doing this.

    When a Li-Ion battery drops below 2.0V or so the copper electrode inside of it literally starts to dissolve. When the battery is recharged this dissolved metal is plated back onto parts of the battery that should not be conductive. This can cause an internal short-circuit which can lead to overheating, venting, or even bursting of the battery. Even if it still works after charging that battery might be damaged and wouldn't be married to the other batteries you used with it anymore.

    It's impossible to say though whether any over-discharging of a battery is unsafe or not since the battery damage is cumulative. The more time it spends at around 2.0V, and the lower the voltage, the more damage is done and the riskier it is to use that battery. If the battery is recharged quickly then the damage is minimal. If the battery slowly self-discharged over months of storage then the damage is greater and the risk is a lot higher.

    I'll always recommend just replacing an over-discharged battery if you weren't able to recharge it right away. If you do decide to use it though I recommend the following...

    - Recharge it as soon as possible.

    - Recharge it at the lowest current setting possible.

    - Stay nearby! You want to be able to stop the discharge immediately if the battery starts overheating or there is some other problem.

    So while the recovery feature can help bring back a battery that was overdischarged you need to weigh the risks versus replacing the battery. Remember, even if you recover the battery it might be damaged and no longer married to its partner(s). Keep an eye on the battery voltages and temperatures for a while to make sure the recovery went well.
  9. CAUTION: You are responsible for your own safety! This table is only meant as a first step for you to use in narrowing down the best choices. Do not use it as the only source of information when picking a charger to use! The conclusions and recommendations I make here are only my personal opinion. Carefully research any charger you are considering using before purchasing and never leave a charging battery unattended! I am not responsible for any damage or injury sustained by anyone using this table to select a charger.


    Click the above thumbnail to open up the full-sized table​
  10. PBusardo was kind enough to offer me a page on his web site and I jumped at the chance. The first article is up. Thank you for this opportunity Phil!
  11. Even though the Sony VTC4 is still in production and genuine ones are available there are vapers who are uncomfortable taking a chance at buying counterfeit Sony batteries. Could the 22A-25A rated LG HD2, HD2C, and HD4 be as good as the Sony VTC4? Let's find out.

    In the graphs below I discharged all four batteries at 10A-20A-30A continuous and 30A pulsed. In the constant current graph all of them ran at about the same voltage at 10A continuous but the HD2C lasted a bit longer. At 20A and 30A continuous the HD2C ran at a higher voltage (hit harder) than the others and still lasted longer. The VTC4 didn't beat the HD2C but it performed a bit better than the HD2 and HD4.

    In the 30A pulse current graph the HD2C lasted a bit longer than the rest with the VTC4 and HD4 about tied for second place. While the HD2C ran at a slightly higher voltage than the others when pulsed they were all very close in performance and I don't think you'd see a difference in actual use.

    So, is there a good alternative to the VTC4?

    Yes, the LG HD2C.
    It not only runs at a slightly higher voltage but lasts a bit longer too. The LG HD4 is a close second in these tests and is roughly equivalent to the VTC4 for vaping at up to about 25A-30A/100W.

    image.png image.png image.png
  12. Those are lithium-ferrous-phosphate batteries, or "LFP". They are also called IFR. They are a different type of Li-Ion chemistry than the ones we use most often when vaping, often called IMR, INR, and ICR.

    The continuous discharge current specifications for these batteries seem to be perfect for vaping; 30A for the 18650 and 70A for the 26650. But there are a few things to consider before using them in a mod...
    • The A123 18650 is only 1100mAh. The A123 26650 is only 2300mAh.
    • LFP batteries have a lower nominal voltage than the IMR/INR/ICR batteries we normally use, 3.3V. While you can compensate for this lower voltage in an unregulated/mechanical mod it means that regulated mods will stop firing and show a weak/low battery message much sooner than normal.
    • LFP batteries need a 3.6V charger. They cannot be charged to 4.2V!
    There is one very important advantage to these LFP batteries though: they are the safest Li-Ion chemistry we can use. The temperature at which they go into thermal runaway is higher than IMR, INR, or ICR batteries. If they do go into thermal runaway the reaction is much less violent than with other chemistries. There are usually no flames and the temperature of the reaction is much lower.

    Does this increased safety, and the high current ratings, make LFP batteries worth using in our mods? In my opinion, no. Being limited to unregulated/mech mod use, modifying the build resistances, and buying another charger is a lot to do just to use a low capacity battery. Even if it is safer when short-circuited.

    The A123 26650 battery might be worth the trouble and low capacity since it has a current rating far above any other 26650. But is it that much better than two 30A IMR or INR 18650's? Not really. Is it safer? Yes, a bit. But if you don't abuse your 18650's and maintain their wraps the extra safety is never needed.

    So, can we use LiFePO4 batteries for vaping? Yes.
    I don't feel they're worth the compromises though. But if safety is your top priority perhaps they might be worth it for you.

    image.jpeg image.jpeg
  13. It's tempting to use very high capacity batteries, over 3000mAh, to try to get more vaping time before needing to recharge. But there aren't any 18650 batteries with a capacity over 3000mAh that have a rating above 10A!

    Batteries like the Panasonic 3200mAh NCR18650B look like a great way to get more vaping time but they're only rated at 4.9A. And the Efest, Imren, and other Chinese-company high-capacity batteries are just rewraps of 10A Panasonic and LG batteries.

    If you vape at under 20W (per battery) or so then you can use the 3200mAh Panasonic NCR18650B.

    If you vape at under 35W (per battery) or so then you can use the over-3000mAh Efest's, Imren's, etc. But Panasonic/Sanyo NCR18650GA, LG MJ1, and LG MH1 batteries are less expensive and possibly a higher grade.

    Can you vape at higher power levels with these 4.9A and 10A batteries? Of course! The batteries won't explode and your face won't melt off if you do.

    But the voltage sag is so severe that at over about 5A-7A you can actually get more vaping time from the 3000mAh LG HG2 and Samsung 30Q. This is because their internal resistance is lower than the over-3000mAh batteries. This allows them to run more efficiently, with less voltage sag, and that means they run for longer before your mod says low/weak battery.

    So, know your batteries and vape safe.
  14. If you want to start going beyond what covers here are a few of the more interesting papers I've read on Li-Ion batteries. They are quite technical though!

    Thermal runaway caused fire and explosion of lithium ion battery:

    Thermal runaway in Li-Ion — getting the missing data: Runaway in Li-ion Article Best Tech Magazine.pdf

    Theory of SEI Formation in Rechargeable Batteries:

    Advanced Technology Development Program for Lithium-Ion Batteries, Thermal Abuse Performance of 18650 Li-Ion Cells:

    Are Lithium Ion Cells Intrinsically Safe?:

    Understanding Lithium-Ion Technology:

    Mechanism of intercalation and deintercalation of lithium ions in graphene nanosheets:
    Mechanism of intercalation and deintercalation of lithium ions in graphene nanosheets | SpringerLink

    In-operando high-speed tomography of lithium-ion batteries during thermal runaway:

    Some thermal runaway and Li-Ion abuse papers: Runaway in Li-ion Article Best Tech Magazine.pdf Ponchaut Paper 2015.pdf

    Aging Mechanisms in Li-ion Batteries:

    Degradation Mechanisms and Lifetime Prediction for Lithium- Ion Batteries – A Control Perspective:
  15. Do I have the qualifications to be doing stuff like this? Some say that I don't.

    You be the judge.

    Since 1992 I have been designing and building electronic devices for a large number of clients. My first products were camera remote-control systems for sports photographers. As these systems, and other devices, transitioned from wired to wireless the performance of the batteries they used was very important as there was no way to replace them during use. This led to me doing more and more battery testing and developing the electronics to charge, test, and protect them.

    As battery technology advanced, from NiCd to NiMH to Li-Ion and now ultracapacitor/Li-Ion hybrids, the devices I built and the battery testing I did advanced along with them. I started specializing in power management electronics; battery chargers, energy harvesters (for charging from heat, light, or vibration/movement), power supplies, battery analyzers, electronic loads for battery discharging, and battery management/protection systems. This is the work I still do today.

    My clients have included the US Army, National Geographic, Sports Illustrated, Eastman Kodak Company, and hundreds of other companies from large to small. Part of the work I've done for a lot of my clients has been battery testing. Sometimes they want to recommend a good battery to their customers. Other times they're batteries I have chosen to combine with my electronics to form a complete, protected power source for them to incorporate into their products.

    Depending on my client's requirements this testing can take up to several weeks to complete. I use a subset of these tests when evaluating the batteries we use when vaping. This includes continuous-current tests to establish the battery's true (and safe) ratings. They also help to determine if there's any risk of venting if one of our mods autofires or a mechanical mod's button is accidentally pressed. The pulse-current tests measure the degree of voltage sag we would see when vaping at different current levels. Both types of tests are done the same way for every set of batteries I test, over 110 different ones to date (almost 400 batteries total).

    This consistency in the testing allows for direct comparison of the performance of different batteries even if the pulse discharging I do doesn't match the way you vape.

    Safety is my number one priority. While I often test at discharge current levels that can result in unsafe battery temperatures, this is the only way to figure out what a battery's true and safe ratings are. No battery is totally safe but we can certainly avoid taking unnecessary risks.

    This is critical.

    There is a huge difference between a battery's rating and a capability of the battery. You might be able to vape with a battery at 40A but that doesn't make 40A the battery's rating. It's just something the battery can do without venting. You still don't how the battery performs compared to others, how much the battery is being damaged, or what the safe limits are.

    A rating is different from a capability because it uses a set of important criteria to establish the rating. Things like temperature, voltage when discharging, cycle life (how many times it can be charged/discharged) are defined and limits are set. This allows for direct comparison of the performance of different batteries and is how I test. The tests determine not only the safety limits of the battery but also the performance limits when vaping.

    In my blog at ECF I have listed the equipment I use and the steps I follow when testing. This allows anyone to replicate my tests if they want to:

    My cell testing equipment and setup | E-Cigarette Forum

    What's done for each cell test? | E-Cigarette Forum

    Does all this make me some kind of battery expert? Hell no. But I do feel I am qualified to do this testing. My results offer you a resource you can use when choosing a battery that will not only be safe for the way you vape but will also give you great performance.

    If there's something you don't like about the testing or the ratings/performance tables, let me know! I'd be happy to read what you have to say and discuss it with you. Over the past few months the feedback I've gotten has resulted in some good changes to the tables to make them less confusing and easier to read.

    Each of us has to decide which battery tester's results we will use. Different testers use different criteria when setting a rating or when comparing batteries. Find out how they test, compare their results, and pick the tester you trust the most with the batteries you use.

    Thanks for your time!
    Katya, Microzod, KS_Referee and 19 others like this.