Replies

    • DG > Cala February 11, 2016 at 4:02pm

      I think if you fly at 2-2.5c the MS work ok. Heck, at $20 for 5200 4s MS, one can throw them away like Bic lighters, as long as they don't malfunction such as a cell failing.

      However, I've heard of people having their MS actually catch fire while flying. Did they overwork them? I don't know. People either love them or hate them it seems. 

      I have found charging at 1c is a good thing to do. I actually have a 10,000 4s MS that's well over a year old and still works, not puffed, but have not checked internal resistance for quite a while. 

      Bottom line for me is basing the choice of battery on the worth of the copter and willingness to accept that it could mean losing one to a crash because the battery voltage drops excessively or fails while in flight.

  • Cala February 9, 2016 at 4:29pm

    Thank's guys for all the info, I hope, in near future we are going to have better and better batteries choices for owr copters for longer flying times.

  • Jeremy Stromsoe February 9, 2016 at 6:14am

    I haven't personally used the batteries... but sounds like a scam/marketing.  

    Here's a 30C 5.2Ah pack, 336g for $30.  A savings of 37%.  And the discharge rate is higher than the Graphene, AND its 27g lighter.  

    MORE importantly it seems that these new packs have decreased the price of the normal packs I use!!  16Ah at 10C on Amazon for ~$60?!  I guess I love these new batteries ;).  Get em while they're hot (intended). 

    http://www.amazon.com/Multistar-High-Capacity-16000mAh-Multi-Rotor/...

  • Moderator
    Graham Dyer February 8, 2016 at 9:33pm

    Rapidly expanding thread on RCGroups here: http://www.rcgroups.com/forums/showthread.php?t=2592234

    Their longevity seems to be amazing (1000+ cycles to 87% capacity) and high real C rating but they are heavy for their capacity so may not be the best choice for most multirotor/UAV pilots wanting lightest weight.

  • Khoa Vu February 8, 2016 at 7:52pm

    This is pretty cool! I'm personally a fan of ThunderPower ProLite+
    http://www.thunderpowerrc.com/Products/ProLite-Power-Series

    I'm trying their Lightning series right now, I may post data soon

  • Cala February 8, 2016 at 6:22pm

    Thank's Forrest and Jose, I was intrigated if holding  better voltage, compenstes more weigh?, I have the 10c ones and very happy with them but always watching for longer flying times.

    • MR60
      Forrest Frantz > Cala February 9, 2016 at 7:59am

      what is your flying time up to now?

    • Cala > Forrest Frantz February 9, 2016 at 4:21pm

      Forrest: in my longer efficient quad is 30 min with two 5200 multistar remaining 20-30%, I stopped with him an dedicate to the other one to resolve flying with wind, that flies 20 min but now it can fly in windy days like today :) 20-30% remaining batts, an covered with leds (It's looks pretty nice :) ) my following step is to change esc and wires on the bigger one to save grams, I have 40A heavy esc and buy 20A hobbywing and thinner wires (18AVG); my idea is to fly one minute in hover after changes and repeat the test before to know results, (I have older test but to be shure). Pixracer looks a good choice to modernice the APM with lighter weight?

      My idea is to have an efficient cuad with only fpv and a little mobius and a pretty clown quad to test different things like the gimbal, lidar lite, rgb leds, windy days, etc. because the two things in one quad is impossible as you tell me some time ago so I resolved like that :)

    • MR60
      Forrest Frantz > Cala February 10, 2016 at 7:42am

      Calculating Battery Type and Size

      So let's figure 20 minutes is your minimum (really good by the way ... you can be proud of doing that).

      For your battery, you are looking for a

      - C rating of 2 (safety factor) x 60 (minutes per hour) / 20 (minutes of minimum flight duration),

      - which equals 6.

      So any battery with a C of 6 or higher is what you need. In battery tech (in general), the lower the C rating, the lighter the chemistry. so you want a C close to 6 (but weight of the battery is all that counts).

      To ensure you are not over taxing the battery:

      - to look at your amps at hover, lets's say 30

      - use the rated C, lets say 10

      - calculate minimum flight time that will not overtax the battery, so 60 minutes / 10C = 6 minutes.

      - double (for wind) or triple (for racing) that time

      - so for casual flight lets say 6 (minutes) x 2 (flight factor) = 12 minutes

      - so the minimum battery size is 12 (minutes) / 60 (minutes per hour) * 30 (hover amps) = 6 Ah

      - then multiply by 1000 to convert to milli-amps or 6000 mAh battery

      So what you need in battery tech (so the battery won't be hurt) is:

      - 10C battery that is > 6,000 mAh

      -  6C battery that is > 10,000 mAh

      - 2C battery that is > 30,000 mAh (if flying Li-Ion)

      Of course, the larger the battery capacity the longer it flies to a point where flight times shorten. The trick if finding the maximum on the flight-time/capacity curve.

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