Here's his 18350 ratings and pulse performance table: https://www.e-cigarette-forum.com/…/18350-safety-grades-a…/… Here's his 18650 true current ratings table: https://www.e-cigarette-forum.com/…/18650-safety-grades-pi…/ Here's his 26650 ratings and pulse performance table: https://www.e-cigarette-forum.com/…/26650-safety-grades-an…/ Excerpts from his blog as posted on ECF:
This is the equipment I use for cell testing: Equipment
- West Mountain Radio CBA IV Pro battery analyzer, modified for low voltage drop . Accuracy = +/-1% up to 20A.
- Custom constant-current electronic load, rated 150A/400W. Accuracy = +/-0.6% up to 150A. A second load is available, if not being used for other testing, if I need to discharge at over 150A (up to 300A).
- Adjustable 5A/30V CC/CV power supply for charging the cell.
- Omegaette HH308 dual type-K thermocouple thermometer. Accuracy = +/-0.3% + 1C.
- 20A, 100A, and 200A current measuring shunts. Accuracy = +/-0.25%.
- Fluke 8846A 6-1/2 digit DMM. Accuracy better than +/-0.01%.
- Low-resistance cell clamping rig.
- Safety glasses, fire-resistant apron, fire-resistant gloves. I wear all when doing destructive testing or if I think the cell temperature will rise much above 100°C. Otherwise just the safety glasses.
- The CBA battery analyzer handles 10% of the discharge current and creates the graphs. The custom load handles 90% of the current.
- The cell has its wrapper removed so the thermocouple can be placed directly against the metal can to sense temperature.
- The thermocouple, plus 0.5" of its cable (to prevent ambient air from cooling it and affecting the thermocouple), are tightly Kapton-taped to the cell with the thermocouple positioned halfway down the cell.
- All discharges, unless noted, are constant-current to within +/-1% of the stated value. Confirmed via +/-0.25% tolerance current shunt.
- All measured temperatures were rounded to the nearest degree-C. Only the highest temperature for the discharge is recorded.
- The cell is placed in an insulated fireproof container with a lid loosely placed on top. The container is left open at the top to allow heat to escape during discharge. If a cell vents the cover is closed and a fan is turned on to evacuate the gas/vapor outside via a flexible metal hose.
- The cell holder is a non-conductive c-clamp using a 1" x 1", 0.040" thick copper plate to connect to the bottom of the cell. A 1/4" diameter copper rod is used to connect to the top of the cell. Both the top and bottom connections have 10AWG and 12AWG silicone-insulated wires soldered to them. The 10AWG wires go to the 400W load and the 12AWG wires go to the CBA, directly soldered to the CBA circuit board. I do not use the CBA's PowerPole connectors as their resistance is too high.
- Why only a 1/4" copper rod for the top of the cell? One reason is that's the equivalent of 3AWG wire...plenty beefy enough. The other reason is that I don't want to conduct any more heat from the cell than I have to.
Updated 10/24/15 to include pulsed discharge tests. For every cell I test, these are the steps I follow... Continuous Current Tests
Pulsed Current Tests
- I use two of each cell for testing.
- Photograph the wrap from one cell and top if a button has been spot-welded on.
- Remove the wrap and photograph the case, top, and bottom.
- Attach the thermocouple (temperature sensor) halfway down the cell with Kapton tape, making sure to cover the tip of the thermocouple to prevent any flowing air from cooling it.
- Clean the test rig contacts with a Scotch-Brite pad and then a 90% alcohol wipe.
- Mount the cell in the low-resistance test rig.
- Charge 18650's and 26650's to 4.20V at 2.5A until the current drops to 100mA. 18350's are charged at 0.5A unless the manufacturer specifies a higher rate.
- Run three constant-current (CC) discharges down to 2.80V to check basic cell functionality, including capacity and temperature. 18650's and 26650's are discharged at 10A. 18350's-18500's are discharged at 5A.
- If all three discharges are essentially identical then I continue. If something keeps changing for each discharge I keep running them until the cell's performance has stabilized. So far, every cell has stabilized within three discharges.
- For each discharge I measure the actual current level using a 0.25% tolerance current shunt and a Fluke 8846A meter. This not only confirms the starting current level but by using the min/max/avg functions of the meter I can confirm that the current level has not drifted.
- Run CC discharges, down to 2.80V, at every 5A increment above that until the cell reaches 100°C or the voltage just quickly collapses.
- Note the maximum cell temperature reached for each discharge.
- After each discharge let the cell cool to below 40°C before recharging.
- Recharge each cell to 4.20V, stopping when the charge current has dropped to 100mA.
- Determine the cell's continuous discharge rating (CDR) by noting the current level that brings the temperature closest to the 78°C average (74°C-82°C range) I measured for the Samsung, Sony, LG cells I tested at their CDR.
- Run an additional two CC discharges at the cell's CDR to check for voltage sag, loss of capacity, or increasing temperature. These are all signs of cell damage and indicate that the cell's rating is too high.
- Run an additional two CC discharges at 5A above the cell's CDR to check for voltage sag, loss of capacity, or increasing temperature. These are all signs of cell damage and indicate that it's being discharged at beyond its rating. It also gives us an idea of hard it can be abused.
- Take the second cell, run the three initial discharges, and then discharge at 10A and at the CDR of the cell. If the results are within 2% of the first cell then the first cell's discharge graph is used. If the discharges of the second cell are different from the first I do not post any test results until I can source another set of cells to test and compare.
I don't have a standard yet for determining the pulse rating for a cell. When I have enough pulsed current discharge data I will give each cell I test a pulse rating. In the mean time you can view the discharge graphs to see what the voltage drop is for the cells I have been testing recently. All of the Samsung, Sony, and LG cells are being retested to add this pulsed current data. Important Notice! Testing batteries at their limits is dangerous and should never, ever be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them. My safety precautions are the ones I have selected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.
- Discharge the second 18650 or 26650 cell at 30A, each pulse is 5 seconds on/30 seconds off, down to 2.50V. 18350-18500 cells are started at 10A.
- A lower cutoff voltage is used for the pulse testing to give those cells that have a significant increase in voltage when hot (due to lowered internal resistance) a chance to warm up.
- Run pulsed current discharges, down to 2.80V, at every 5A (for 18350-18500) or 10A (for 18650-26650) increment above that until the cell reaches 100°C or the voltage drops to 2.50V for the first pulse.
- After each discharge let the cell cool to below 40°C before recharging.
- Recharge each cell to 4.20V, stopping when the charge current has dropped to 100mA.
- Note the maximum cell temperature reached for each discharge.
There are several things you can do to help your Li-Ion batteries last as long as possible before needing to replace them. Some are easy, some are quite inconvenient. Some have a big effect, some very little. But doing any of them can help slow down the aging and degradation of your batteries. Temperature
- Don't overheat them. High temperatures are the biggest cause of battery damage and reduced battery life. Anything over about 45°C/113°F, what most would call warm, and your batteries start aging faster. The more time they spend being warm or hot, and the hotter they get, the more damage you're causing.
- Don't use them when they're very cold, below -20°C/-4°F. The chemical reactions in a battery are a lot less efficient at low temperatures leading to poor performance. The sudden heating of the battery if used when cold can cause localized internal heating, possibly damaging the battery.
- After using your battery, let it cool to room temperature before charging it.
- Don't overdischarge them. Our batteries are rated down to 2.5V or lower but you can extend their life by staying above 2.8V-3.0V***. Going below 2.0V or so leads to metal being plated inside different parts of the battery, eventually causing an internal short circuit and possible bursting of the battery.
- If you accidentally overdischarge your battery below 2.0V immediately recharge it at the slowest rate your charger supports. Once the battery rises up over 3.0V or so you can switch to your normal charge rate.
- If battery has been at 2.0V for a while then it's probably damaged. It's not worth trying to use the "recovery" mode of your charger (if it has it) because the damage can lead to an internal short circuit later.
- Li-Ion batteries do not need to be discharged occasionally all the way down in order to keep them in top condition. Li-Ion batteries do not suffer from "memory". This is only needed for NiCd (nickel-cadmium) or NiMH (nickel metal hydride) batteries.
- Partial discharging and recharging multiple times is better for long battery life than discharging all the way down to where the mod indicates "low battery" and then recharging.
- After charging, let your battery cool to room temperature before using it.
- Don't charge a battery that is below 0°C/32°F. It causes metal to be plated inside the battery eventually leading to an internal short circuit and possibly bursting of the battery.
- Where possible, setting your charger to 4.1V will reduce stress on the battery and extend its life. But you will lose 10%-15% of the capacity of the battery.
- Make sure the charger you use turns off once the charge is complete. Check the instructions for the charger you want to use.
- Never use a trickle charger with Li-Ion batteries! The continuous holding of the battery at the trickle charge voltage damages it.
- Don't overcharge them. To get the longest running possible time from a battery some chargers go up to as high as 4.27V. While this does result in a bit more vaping time before needing to recharge, it damages the battery. Most of the batteries we use are rated at up to 4.25V but even this is quite high. It's not dangerous until we're approaching 5V but battery damage starts occurring way below this.
- Without a separate meter monitoring the battery's highest voltage before the charger stops it's hard to know what our batteries are actually being charged to. Our best option is to have our batteries spend as little time as possible fully charged and charge them just before using them. This usually isn't very convenient but it does extend battery life.
- Charging at a slower rate is better, to a point. Most of our 18650 batteries have a "standard" charge rate of 1.0A-1.5A and a "rapid" charge rate of up to 4A. Charging at 0.5A might help extend the life of your batteries a bit but if the batteries are not getting warm at 1.0A then that's a good compromise between battery life and convenience. Going down to 0.375A or 0.25A won't help much versus charging at 0.5A.
- Charge 18350's at 0.5A until you know that they aren't getting more than a bit warm.
- Charge 26650's at 1.0A until you know that they aren't getting more than a bit warm. The better 26650's can be charged at up 2.0A without adversely affecting battery life.
Additional Information ***This is the resting voltage, NOT the voltage "under load" that the battery drops to when being used. If your mod stops firing when the battery drops to 3.2V the battery can rise back to to 3.5V or even higher after resting for a while. This "resting voltage" is the important voltage, the one to be used when determining how low you are really discharging your batteries. While stopping at 3.4V, 3.6V, or even higher might extend battery life a bit you are missing out on a lot of additional vaping time that you could use before needing to recharge. That additional vaping time can be enjoyed every day for, at most, just the cost of one extra set of batteries a year. Stopping at these higher voltages won't hurt the battery though. Just let the batteries sit for an hour before charging to see what their true resting voltage is when deciding how low you want their voltage to go in your mod.
- Storing batteries in the refrigerator doesn't make much of a difference in battery life unless you live in an area with high temperatures year around. It's not dangerous to refrigerate them but be sure to let them come to room temperature before opening whatever airtight wrapping/container you have them in.
- If a battery wrap becomes damaged, replace it immediately. Replace the top insulator ring if it's also damaged.
- Every time you buy batteries also buy battery boxes or sleeves, wraps, and top insulator rings. You...will...need...them.
- When you start getting earlier and more frequent "low battery" alerts from your regulated mod even though you haven't increased the power.
- When you notice that your mechanical/unregulated mod doesn't hit as hard, or for as long, as it used to (before needing to recharge your battery).
- If your battery starts getting warmer during use or charging even though you haven't changed power settings or your coil resistance.
- If your charger will no longer get to 4.20V before stopping. Make sure the charger is functioning properly and try switching charger bays before replacing the battery though.
- If you see physical damage to the metal top or can of the battery. Things like dents and deep scrapes should not be ignored! A damaged wrap and top insulator ring can be replaced without needing to replace the battery.
- If the battery vents and leaks fluid, even the smallest amount. Continuing to use a battery after it has vented can lead to the battery overheating and possibly going into thermal runaway and bursting.
- If the battery has rusted badly. You don't need to worry about a few small spots but if they are pushing the wrap up or growing larger then replace the battery.
- If the battery discharged down below 2.0V for a long period of time. Accidentally discharging down below that for a short period of time is ok. But if you left a battery unused for a long period of time and it's now dropped below 2.0V, replace it. You might be able to "recover" the battery with certain chargers but it's probably damaged and it's just not worth it.
- There's no need to replace a battery on a fixed schedule, e.g., once a year. Those who use their batteries at high power levels might have to replace them every few months, or even sooner. Low power vapers can easily get a couple years of use out of their batteries.
- Never throw your battery in the trash! Please recycle it. Many electronics or home improvement stores and vape shops will accept your batteries for recycling. First give the battery a couple of wraps in whatever tape you have to insulate it from any metal it might touch.
- You do not need to replace a battery if you dropped it but there's no physical damage
Inside each battery there are two things that can interfere with the flow of current in or out of the battery. The two of them together are called the internal resistance of the battery. Why is internal resistance important? It's what causes your battery to heat up and the voltage of your battery to sag. So what are the two things that add together to create the the battery's internal resistance? First, it's the actual resistance of the metal contacts and the internal structure that carries current through the battery (the electrolyte, separator, etc.). This resistance is typically only a few milliohms (thousandths of an Ohm) to a couple dozen milliohms. Second, it's the efficiency of the chemical reactions and flow of the ions through the battery. These ions can't be transported through the battery at any rate we want. As the current level rises there is a difference in the density of the ions in different parts of the battery. This change in the density and distribution of the ions results in a voltage difference between different points of the battery. We see this effect as a voltage change as soon as current flows. Knowing the voltage change and how much current is flowing we can use Ohm's Law to determine the equivalent resistance that would cause the same voltage change. These two resistances added together (one actual and one equivalent) give you the internal resistance of the battery...or the IR. The "DC IR", direct current internal resistance value, is the one we want to use. Since we pulse our batteries for up to several seconds we want to use the IR value measured when switching between two steady current values, one of them being zero amps in our case because we pulse our batteries on/off. The "AC IR" value often quoted in battery datasheets is lower but this is something we would use only when measuring performance in an unregulated PWM device. It's measured by pulsing the current at 100Hz or 1000Hz. The typical DC IR (which I'll just call IR) of a new Samsung 25R battery at room temperature is roughly 0.022-0.025 ohms. For a high-capacity 5200mAh 26650 battery the IR can be as high as 0.06 ohms. This is what causes the large voltage sag when we try to vape with these high-capacity 26650's at higher power levels. The IR of a battery affects how we vape by causing the voltage to sag during discharging and the voltage to rise during charging. Since these voltage drops or rises are just temporary, and aren't the true voltage of the battery, this can be a problem.
I wanted to outline some of the differences in the safety of the chemistries used in our batteries. The Battery Bro website has a fantastic explanation of the different chemistries themselves: Battery chemistry FINALLY explained. Before we go into the chemistry differences lets define the two different events that can occur if the battery is abused too hard; venting and thermal runaway. -- Venting -- Venting is a purely physical process that releases excess pressure that forms inside a battery if it is discharged too quickly or charged at too high a voltage. Both of these situations cause excess gas to be created and that increases the pressure inside the battery. Each battery has a pre-weakened area of metal underneath the top contact. At a certain pressure level the weakened metal splits open and allows the pressure to escape. The solvent for the battery's electrolyte often oozes or sprays out too. This can be a problem because not only is it toxic but venting typically happens at around 130°C-160°C, which means the liquid is very hot. Venting can be a rather gentle event or it can be a pretty energetic spurting and spraying of gas and liquid. Be careful, that liquid is toxic and flammable! The battery does not burst and there are no sparks or flames. The amount of gas produced is relatively small and can usually be handled quite easily by the venting holes we see in mods. Once a battery vents, even just a little, it is ruined and should never be used again. -- Thermal Runaway -- This is a catastrophic failure due to uncontrolled chemical reactions inside the battery. It always results in the bursting of the battery, sometimes quite violently, and can be accompanied by sparks and flames. As the temperature of the battery rises during a discharge, certain exothermic chemical reactions can start as the temperature goes above about 75°C. This is the beginning of the process that can lead to thermal runaway if these reactions are not stopped. If not being discharged too quickly, or the battery is being cooled a bit by ambient air flow or a metal mechanical mod tube, these new reactions can stabilize at a certain rate and not continue to increase the battery temperature. If the discharge current level is too high, or there's no cooling, then these reactions keep increasing the temperature of the battery. This causes more exothermic reactions to begin, which heats up the battery even more, which causes even more reactions to begin, and so on. As the battery reaches about 125°C the plastic sheet (the "separator") between the two sides of the battery, positive and negative, begins to melt. This can lead to small short circuits forming at different points in the battery. These short circuits increase the temperature at those points, further increasing the rate that the battery temperature rises. As the temperature continues to rise certain compounds start decomposing and releasing large amounts of gas. This increases the pressure inside the battery and, hopefully, leads to venting of the battery to release the pressure. But if the temperature and pressure buildup happens quickly enough, the battery won't vent in time. At about 230°C - 270°C the thermal runaway threshold temperature is reached. This is where there the materials inside the battery are decomposing incredibly fast. There is a huge buildup of gas and the battery bursts open, often ejecting its contents and throwing pieces of battery a long distance. Depending on the threshold temperature the solvent can also ignite, resulting in a fireball to accompany the shrapnel. While it can be quite violent, this isn't the explosion seen in a few videos that have made their way through the vaping groups and forums. Those explosions happen when a device doesn't have a pop off side panel or large open areas for the pressure to escape. The device holds back the gases for a bit but eventually it can't withstand the increasing pressure and it explodes. It is quite difficult, but not impossible, to bring the temperature of a battery up quickly enough to go into thermal runaway without it venting first. About the only way to do it is with a short circuit. Both venting and thermal runaway can take hours to occur or they can happen very quickly. You will typically be able to feel a battery getting hot before it vents but do not assume the same for preventing thermal runaway. That depends on a very, very fast rise in temperature, happening before the battery can vent. You might not feel the battery get hot first. How do we prevent thermal runaway then? Never allow our batteries to be short circuited! Keep your battery wraps and top insulating rings in perfect condition, replacing them when necessary. Never use an atomizer with a press-fit or spring-loaded 510 pin on a hybrid top mechanical mod. Always make sure that the 510 pin sticks out past the threaded stem of the atomizer. -- Differences in Battery Chemistry Safety -- Each chemistry has different characteristics that make it safer or less safe than another. The attached table makes some basic comparisons between their safety. As the table outlines, ICR is the least safe, INR is safer, and IMR is the safest of the three. IFR batteries (lithium-ferrous-phosphate), like the ones from A123 , are the safest Li-Ion chemistry. Their lower nominal voltage, 3.3V versus 3.6V-3.7V, causes problems for regulated devices though. The "low battery" warning comes on much sooner than when using the higher voltage chemistries. The term "IMR" is being used by some battery companies as a generic term for any of their batteries that aren't ICR. These "IMR" batteries can be true IMR chemistry or one of the hybrid INR chemistries. While not accurate this isn't a safety issue as both IMR and INR are the safer chemistries. Not safe...safer. Any battery can be unsafe if abused enough. ICR batteries are not recommended unless you are very familiar with your device, Ohm's Law, and battery safety. The consequences of abusing these batteries is much, much worse than with IMR and IMR.-- Conclusion -- This can all sound quite ominous, making every battery sound like a bomb waiting to blow. While Li-Ion batteries can be dangerous if abused, we shouldn't fear them. A little knowledge and respect goes a long way towards making sure we never have problems. Know your batteries and vape safe!
Calculating the current being drawn from the batteries in a regulated device can be very confusing. You can't do it the same way as you would for a mechanical/unregulated device and there are so many different battery configurations; single, dual parallel, dual series, triple series, etc. The way I keep it all sorted out is to remember that, in a regulated mod, the coil isn't connected to the battery. The regulator is. To calculate the current being drawn from each battery when using variable-wattage (VW) mode you need to calculate the maximum wattage each battery supplies. Here's how I do it... As an example, the Reuleaux has a maximum wattage rating of 200W. Since it uses three batteries that means each battery supplies 200W / 3 = 67W. For dual parallel or series 150W devices each battery supplies 150W / 2 = 75W. You use this method for series or parallel devices, it doesn't matter. Once you have the maximum wattage for each battery then you can use the following formula to determine the maximum amount of current that can be drawn from each battery... Max Amps Per Battery = Max Wattage Per Battery / Minimum Voltage Per Battery For the Reuleaux the minimum possible cutoff voltage is 9.0V, which is 3.0V per battery (unless you set the cutoff higher). For most other devices the minimum is 3.2V or 3.1V per battery. Let's use the Sigelei 150W TC device as an example. This device has a minimum battery voltage of 6.4V, which is 3.2V per battery... Max Amps Per Battery = 75W / 3.2V = 23.4A So you want a battery that can safely supply 23.4A of current if you're using the mod at its maximum rating of 150W. I should add that to get as close as possible to calculating the max current being pulled from your batteries you should add an additional 5%. This will account for the inefficiency of the regulator. For example, if your device draws 23.4A then add 1.17A for a total of 24.6A. Not a big difference, but it's there. That changes the equation to... Max Amps Per Battery = (Max Wattage Per Battery / Minimum Voltage Per Battery) / 0.95 If you know you will not be exceeding a particular wattage that is less than the maximum then you can use that wattage in the equation instead. This often means you're able to use a higher capacity battery like the HG2 or 30Q instead of a high current rated, but lower capacity, battery like the VTC4 or HB6. It's worth doing the math to find out. This works for series or parallel devices. It does not matter how they are connected as we are already taking that into account when we calculate the max power for each battery. It takes much longer to explain all this than it does to actually calculate the amount of current being drawn from your batteries. I hope this helps make the very confusing process of determining how much current is being drawn a little bit easier.
Have you considered using a battery because of its high pulsed current rating? At first glance the pulse rating seem to make a lot of sense. After all, when we vape we don't run our batteries continuously. We only use them for a few seconds at a time. And considering how much higher the pulse ratings are, versus the continuous current ratings, it's very tempting to choose a battery based just on its pulse rating. Don't! There are no standards for these pulse ratings. One battery reseller could base their rating on taking 4 second draws every minute and another might base their rating on 10 second draws every 20 seconds. These two examples will result in very different temperatures and performance. The same battery could get a 40A rating one way and a 30A rating the other way. This makes comparing batteries by their pulse ratings very difficult, if not impossible. But that's not the worst of it! What happens if our regulated mod autofires or our mechanical mod's button gets stuck on or accidentally pressed in our pocket? If we have set up our mod with a low resistance coil that forces us to only rely on a battery's pulse rating, we could be in big trouble. We could easily overheat the battery, causing it to vent or perhaps even burst. Choosing which battery is best to use based on pulse ratings is not only practically impossible, it can be unsafe too. So how should you choose a battery to get both the most power for your mod and still be safe? Either go by the continuous discharge rating (CDR) or find a reviewer that tests batteries beyond the CDR and records temperatures to know when it becomes unsafe. But for longer battery life, consider running your batteries below their CDR. It adds a greater safety margin as the batteries age and lets them run cooler. I have set up a table of safety "grades" for all the batteries I have tested to date. This table shows you what discharge current levels are safe and which might be dangerous for each battery. It can be used as part of choosing which battery might be best for you: 18650 Safety Grades -- Picking a Safe Battery to Vape With For more detailed information on the batteries I've tested, here's a list of links to the results of each test: List of Battery Tests If you're considering using a battery that has a rating above 30A, check this out before you buy them: There are no 18650 batteries with a genuine rating over 30A!
We've all seen them, the batteries with 35A (35 amp) or higher current ratings. And it seems that they would be the perfect choice for mech (mechanical mod) users or really low ohm coil builds, doesn't it? Except for the fact that as of July 2015 January 2016 there are no 18650 batteries rated at above 30A continuous available to us vapers! Batteries are manufactured by only a handful of companies like Samsung, Sony, and LG. It takes millions of dollars to start up even a modest battery production line. The companies you see selling these high-amp batteries are just too small to be able to afford that kind of investment. So where do they get the batteries from? The established battery manufacturing companies like Samsung, Sony, and LG! These smaller companies buy the batteries, rewrap them (i.e., they put their own "wrap", or sleeve, on them), boost up the current and capacity ratings, boost up the price too, and sell them as high performance batteries. This is how we know that there are no 35A or higher rated 18650 batteries out there. None of the big battery companies make them! Since these battery rewrapping companies use the same batteries that we can buy at a lower price with the original manufacturer's wrap still on them, why should we buy them? In my opinion, no reason at all unless they are the only ones you can get. Can these 35A and higher rated batteries actually be used at those high current levels? Technically, yes. Those high current ratings are just "pulse" ratings, passed off as continuous current ratings. This means those batteries can only be used at those current levels for short pulses of current. You might be thinking that this isn't a problem because we only vape for a few seconds at a time. But using them like that isn't safe. Since battery rewrapping companies typically exaggerate the ratings by quite a lot, or pass off the pulse rating as the continuous current rating, we don't know how hard we can safely run those batteries continuously. And this can lead to big problems if we have a regulated mod that autofires or if we have a mech mod and its button sticks or is accidentally pressed in our pocket. Without knowing the battery's true continuous current rating this could easily lead to the battery spraying hot, toxic stuff inside your mod ("venting"). Or worse, it could cause the battery to go into "thermal runaway" where the temperatures rise tremendously and the cell violently bursts open. To help you figure out how hard you can run different batteries, take a look at my 18650 Safety Grades table. It can help you narrow down your choices: 18650 Safety Grades -- Picking a Safe Battery to Vape With | E-Cigarette Forum For some great information on batteries and battery safety (and many other topics), see Baditude's blogs: (18) Baditude's Blogs | E-Cigarette Forum And don't be afraid to just ask for advice here at ECF. If you see a battery that you want to buy, but aren't sure if it's safe to use in your mod, please ask us! We want to see everyone vaping safely and will be glad to help. So, are there 30A batteries? Only one, the LG HB6 1500mAh 18650. You can see the classic tradeoff between capacity (number of mAh) and the current rating here. Typically, if you want high capacity you can't have a high current rating. And vice-versa. If you see a battery with both, check around for test results or a review before buying it. There are other batteries that handle almost as much current as the HB6 though. I recommend the Sony VTC4 as the best all around battery for over 20A. At around 20A it's hard to beat the Samsung 25R. Just be sure to buy from a reliable vendor that carries genuine batteries, like one of these (in no particular order)... illumn.com rtdvapor.com orbtronic.com liionwholesale.com imrbatteries.com So be careful of these batteries boasting that they're rated above 30A and vape safe!