The costs of running this huge site are paid for by ads. Please consider registering and becoming a Supporting Member for an ad-free experience. Thanks, ECF team.

All 30A-Capable Batteries Pulsed Shootout -- Bench Test Results -- Some changes when pulsed

Discussion in 'Batteries and Chargers' started by Mooch, Aug 2, 2015.

Thread Status:
Not open for further replies.
Image has been removed.
URL has been removed.
Email address has been removed.
Media has been removed.
  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    This is the second part of a test ("shootout") of all the batteries I have tested to date that in my opinion can be safely discharged at 30A. This does not mean that you will get good battery life discharging them this hard! Only that if there is a mod malfunction the batteries shouldn't become hot enough to vent. The first part of this shootout was done with constant-current discharges:

    All 30A-Capable Batteries Shootout -- Bench Test Results -- Which battery is best? | E-Cigarette Forum

    This second part of the shootout was done with pulsed 30A discharges. Each pulse was 4 seconds long, with 30 second rests in between. This on/off timing was selected as a result of the poll I posted to find out how long the typical vape draw is and how long we take between draws. A longer wait between draws was a very popular poll choice but would result in tests that took a very long time to complete. In a quick test, I saw no difference in battery performance using 30 seconds between draws instead of 60 seconds.


    Disclaimer
    The conclusions and recommendations I make based on these tests are only my personal opinion. Carefully research any battery you are considering using before purchasing.

    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.

    Caution: You are responsible for your own safety! These graphs are only meant as one step for you to use in narrowing down the best choices for the way you vape. Do not use it as the only source of information when picking a battery to use! This is especially true if you intend to use a battery at over 50% of its continuous current rating. I am not responsible for any damage or injury sustained by anyone using these graphs to select a battery.


    Pulsed Discharge Shootout Results

    Pulsed-Current graph, x-axis in mAh
    image.jpg

    Pulsed-Current graph, x-axis in minutes
    image.jpg

    Constant-Current graph (for comparison)
    image.jpg


    Comments
    • While there are no fundamental changes between the constant-current (CC) and pulsed-current (PC) discharge results, there were some minor differences worth noting:
      • The VTC4 trailed the HD2 for the CC test but beat it in the PC test, running longer by about 12 seconds of vaping time and having about 3W more power during use.
      • The HB6 fell behind the Efest in the PC test, versus the CC test, by about 24 seconds of vaping time. I think the PC discharges favor the Efests higher rated capacity versus the HB6's lower internal resistance (i.e., cooler running temperature). The HB6 hits a little harder at the start of the test but drops a bit below the Efest as the Efest's greater capacity holds up its voltage longer.
    • The Aspire 1880mAh ICR still did quite well in the PC test, having the highest voltage under load and the longest running time. It has passed all the important safety testing without catching fire or exploding (like just about every cell in those tests it did vent though). But it is an ICR cell and each of us must decide on our own whether that is a concern or not.
    • The rest of the results pretty well mirrored what was seen in the CC tests.
    • Temperatures were not recorded for the PC tests because all of these cells had been previously tested with CC discharges and found to not have exceeded 100°C, my safety limit, during a continuous discharge to 2.8V at 30A. During these PC tests all of the cells stayed within a 5°C spread around 47°C.

    Batteries In This Shootout (links to my tests of each)

    Aspire 1800mAh 18650 Bench (Re)Test Results....beats the 25R, equals the VTC4 | E-Cigarette Forum

    Efest 38A 2100mAh 18650 Bench Test Results...an ok 20A cell, no higher | E-Cigarette Forum

    LG HB6 30A 1500mAh 18650 Bench Test Results...better than SX30 at >25A | E-Cigarette Forum

    LG HD2 25A 2000mAh 18650 Bench Test Results...too hot at 25A, but OK 20A cell | E-Cigarette Forum

    Sony VTC3 30A 1500mAh18650 Bench Test Results...a 25A cell you can use to 30A | E-Cigarette Forum

    Sony VTC4 2100mAh 18650 Bench Test Results...a 20A cell that can be used to 30A | E-Cigarette Forum


    Additional Information

    For more information regarding which batteries can be used at certain discharge current levels, see my 18650 Safety Grades table: 18650 Safety Grades -- Picking a Safe Battery to Vape With | E-Cigarette Forum

    For all kinds of great information on batteries (and other topics), see @Baditude's blog:
    (18) Baditude's Blogs | E-Cigarette Forum
     
    • Like Like x 6
  2. Froth

    Froth Ultra Member Verified Member ECF Veteran

    Mar 1, 2014
    Chipotle.
    OH YES, SWEET DATA. That Aspire has me considering it...though I'm not entirely comfortable with ICR based chemistry. I was going to overlay the Samsung 25R pulsed discharge you did to compare but I realized that is a 5s on 30s off graph, and thus will not compare well.

    Looks like that previously deplorable Efest cell woke up with vape style usage test, Pulse discharge isn't discussed nearly as much as it should be, none of us vape at continuous drain so why be bothered with a specification meant for an entirely different industry and usage? As I've said before, I pretty much constantly use the 25R at 0.12 ohms and I've run cells to cutoff voltage with pulse usage at that resistance without noticeable heat/warmth in my hand at all from the battery. Not entirely sure I can depend on the ICR Aspire cell to do the same.
     
  3. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Only one way to find out how that Aspire cell will do. :)

    You could use the mAh number from the 25R pulsed discharge to get a decent idea of its performance when compared against the mAh numbers here. Not too much of a difference between 4/30 and 5/30 test on/off times. Or, eventually I'll have the 20A shootout tests done....some day...lots of cells!

    The constant-current tests are the only way we can set safety limits for the pulsed discharges so they do still serve an important function. And they're great for quick comparisons between the results from different testers.

    But, pulsed tests seem to be a bit more accurate than constant-current tests (at very high current levels at least). If there was some sort of vaping community standard for pulse testing I think it would become a lot more popular.
     
    • Like Like x 2
  4. Froth

    Froth Ultra Member Verified Member ECF Veteran

    Mar 1, 2014
    Chipotle.
    What concerns me is the differing data I find from numerous places, Kidneypuncher for instance has been doing pulsed tests for a while now and at 0.20 ohms with their testing equipment it appears the 25R is nearly identical in performance. Kidneypuncher does a 10s on 20s off test style and I took the liberty of overlaying their graph for the Aspire 1800mah ICR and the Samsung 25R2 Blue wrapper. Note, In my overlay I greyed out the batteries I didn't want to compare so this is just the Samsung 25R(Blue line on graph) and the Aspire 1800 ICR(Red line on graph).

    [​IMG]

    Very very close, I'm not aware of what specifications or where they get their test cells from, but an overlay of the same graph with the same style testing is nice data IMO.

    Edit: Source - 18650 Battery Tests
     
    • Like Like x 2
  5. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    I agree. Certainly for any of my graphs, each battery is discharged the same way.
    I don't know if we'll ever get everyone to test to the same on/off timing and current/resistance levels though. I think Kidney Puncher has some tests done at 4s/30s or 4s/20s though.

    At the 10s/20s on/off settings that Kidney Pincher's tests use, the 25R and Aspire could be equal. There might not be any difference between my results and his. The 25R exceeds my 100°C safety limit at 30A so it was not included in the 30A shootout. Both the 25R and Aspire (and a couple dozen more cells) will be in my 20A shootput though.

    Pardon my question..were you concerned about different test parameters being used by each tester or by different results gotten for the same cell by testers using the same parameters?
     
  6. Froth

    Froth Ultra Member Verified Member ECF Veteran

    Mar 1, 2014
    Chipotle.
    My concern is more with inconsistent data with the same parameters being used from the same source, for instance Kidneypuncher has a test that show the 25R Vs the VTC5 at 0.20 ohms 10s on 20s off and the VTC5 starts out with the very first 10s discharge having a voltage under load of right at 3.50V but now compare that to the latest VTC5 only graph they have, which is ALSO tested at 0.20 for 10s on, 20s off and that initial discharge only drops down to 3.60v or perhaps even a little more under load, it is not until the seventh discharge that the voltage reaches 3.50v under load. So...what changed? Even more dismaying to me is the older tests on Kidneypuncher with the "older tester" where it clearly shows the 25R is ahead of the VTC5 with the exact same test parameters. So again, what changed?

    Part of me wonders if the results could be skewed in favor of selling more of a product that has a higher profit margin, but that's sheer speculation on my part.
     
    • Like Like x 1
  7. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Could be....but there are a few things that can make comparing tests run at different times difficult to do.

    - He could have used two different cells. A 0.1V voltage-under-load difference is only a 2-3% change. That is more than the battery to battery manufacturing tolerances I typically see when testing, but not unheard of. Each battery has a different capacity and internal resistance. This can account for different runtimes and voltages under load.

    - His charging for those cells could have been different. Using a different bay in a charger can result in charging to a slightly higher or lower voltage, helping to throw off the tesults. Using a different charger, with a different end-of-charge-current setting can result in a cell being charged more completely than one in another charger.

    - Test rig changes. When used on its own, without a separate load to take the brunt of the discharge current, the CBA IV he uses can have a very large voltage drop at higher current levels depending on how you connect it. If he made any changes to his testing setup between those tests you mentioned it could easily push the results one way or another.


    I don't know if that is what is happening but...maybe.
     
    • Like Like x 3
  8. Froth

    Froth Ultra Member Verified Member ECF Veteran

    Mar 1, 2014
    Chipotle.
    Those are all valid points, would a large change in ambient temp cause that much of a difference? I'd be inclined to include ambient temp/starting temp as well as starting voltage to the hundredths.

    How much of a change can moderate to severe external cooling affect the discharge curve?
     
  9. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Good question!
    The 3°C-5°C differences in my testing ambient temperatures didn't make a difference in early mini tests I did to see if I needed to build a temp regulated box. Any differences due to temp changes were lost in the "noise" caused by other variables. However, doing a test in a chilly room in Winter and then another test in a hot room in Summer might make a difference.

    External cooling (air flow) has a big effect on cell temperature and this affects its internal resistance...which affects its voltage under load. I haven't tested by how much though because I block ambient air flow from cooling the cells (but I don't cover them). Using a fan or perhaps having a nearby air conditioner running could skew results a bit. I can't emphadize how much I wish all cell testers included accurate temp measurement as part of all testing. it's critical for actually setting a true CDR and it can tell you a lot about cell stability at higher temps.

    Good point about starting voltage...
    All my tests start with cells charged to 4.20V to a charging current cutoff value of 100mA using a cc/cv power supply (see my test setup blog). This cutoff is critical too as a charger that cuts off at 1/10 the bulk charge rate (a common spec) could stop at 200mA. This would charge the cell less than using a charger with a cutoff of 50mA. Or one that never cut off. Though never cutting off is not good for the cell.

    Don't know the setups for other testers.
     
    • Like Like x 3
  10. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Great questions and observations ya' got! Interested in doing some cell testing?
    There are still dozens left. :)
     
  11. EddieAdams

    EddieAdams Ultra Member Verified Member ECF Veteran

    Feb 16, 2013
    New York
Thread Status:
Not open for further replies.

Share This Page