Turnigy 20C-40C 1800mAh 3S LiPo Pack Bench Test Results...only an 11C/22C pack

Discussion in 'Batteries and Chargers' started by Mooch, Mar 20, 2017 at 6:49 AM.

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  1. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    To prevent any confusion with the eGo-type "batteries", I use the term "cell" here to refer to a single 18350, 18650, 26650, LiPo pouch, etc.

    While the test results are hard data, the conclusions and recommendations I make based on these tests are only my personal opinion based on my criteria for setting a rating. Carefully research any cell you are considering using before purchasing.

    Testing cells or packs 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.

    If the cell or pack has only one current rating number on it, or if it says "max", then I have to assume that the company is stating that the cell can be discharged at that current level in any way, including continuously.

    image.jpeg image.jpeg


    Bottom Line
    This Turnigy is an average performing pack but is overrated. At 36A (20C), Turnigy's continuous current rating, it reached about 10°C over the pack assembler's limit and was puffed by a decent amount (temporarily) indicating that the cells were being overstressed. This cannot be considered a 20C continuous-rated pack.

    Vaping at its 72A (40C) "pulse" rating would quickly bring the pack voltage down to about 10V and quickly heat the pack up past Turnigy's max temperature rating unless vaping quite slowly. This cannot be considered a 40C pulse-rated pack.

    CAUTION: LiPo's use the most volatile of the Li-Ion battery chemistries and can cause extreme injury if abused. Never use a LiPo unless the cells, wraps, wiring, and connector are in perfect condition. Never exceed the CDR of the LiPo unless you accept the risks involved. You are responsible for your own safety, be careful!


    My Ratings
    • Capacity = 1800mAh
    • Continuous Discharge Rating (CDR) = 20A (11C)
    • Maximum Vaping Amps rating (MVA) = 40A (22C)
    • MaxSafe rating = 50A
    • Average Pack IR = 19.6 mOhms
    • Average Cell IR = 5.1 mOhms

    IR = Internal Resistance
    mOhms = milliohms


    Continuous-Current Test Results
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    Pulse-Current Test Results
    image.png image.png


    Comments
    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.

    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.


    To see how other packs and cells have tested and how hard you can safely push them, check out this link:
    List of Battery Tests
     
  2. Barkuti

    Barkuti Senior Member

    May 3, 2016
    Interesting. Is this pack's weight tantamount to ≈3x 18650s?
    I wonder how would this compare to a pack of high discharge brand name cells. The internal resistance of the stuff is quite low, which of course can help with proper power delivery in short bursts, if not because of its train wreck thermal design. :confused:
    Would be cool to see 3S VTC5A/HB6 extrapolated curves against that. :)

    Cheers :D
     
  3. Mooch

    Mooch Electron Wrangler Verified Member ECF Veteran

    Supporting member
    May 13, 2015
    Even a fairly crappy LiPo beats out the best 18650's due to the lower cell and cell interconnect resistance of the LiPo setup. The battery sleds used by the vaping community are truly terrible and cause huge voltage drops.
     
    KenD likes this.
  4. Barkuti

    Barkuti Senior Member

    May 3, 2016
    Seems its internal resistance drops as it heats up. Briefly after continuous discharge start, I observe ≈30mΩ, a value which later on further drops.
    It's a pretty hefty advantage over a standard high discharge 3x 18650 configuration, connective resistances aside (which can be nearly eliminated with heavy wiring and low temp solder interconnections/spot welding). 18650s, on the other hand, could be easily air-cooled over an airframe, rendering good service life, something I suspect these LiPos won't have. Not of much use for you I guess, unless you're willing to unwrap the cells, install heatsinks on 'em with Sekisui 5760 thermal interface, and add fans. 0K, fair enough with this phantasy. ;)

    Cheers :pop:
     

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