What Batteries Are You Using?

Discussion in 'CineStar FAQ - Tips and Tricks' started by Josh Lambeth, Sep 27, 2012.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Crap... that is NOT the answer I was looking for... I was under the impression it was a 40C continuos discharge... I haven't had a chance to test it yet... I may try to send this back now then if it isn't working for you. I need more batteries though and could get two 6200's for the price of one of these 11,000's.

    What did Clints email say?

    Josh
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    I'm with you on the 40C. At 11 Amp Hours that translates to 440 Amps Max discharge rate, if my understanding is correct. For the QC6200 at 50C burst, that's 310 Amps. So I'm still a puzzled why I don't see better performance from the Maxamps 11000.

    Here's the relevant part of Clint's email:

    [....] my guess is that you need to run a higher rated battery like our 100C-150C packs instead. Higher rated packs will always hold voltage better. How well a pack can handle a load is much more important than the total capacity it is capable of delivering. Capacity does not equal power. Especially when you are only discharging a small portion of the packs capacity by having your cutoff set at 3.6v per cell. If you are only draining 2000mah for example, it doesn’t really matter whether your pack is 6200mah or 11000mah, it matters how well it holds voltage during that 2000mah discharge. Does that make sense?

    The Quadrocopter 6200 battery pack is a 25C constant, 50C burst pack which is about twice as capable of delivering power and holding voltage as our 11000 pack. That is part of the reason it gave you a little longer flight time. The longer the battery can keep that voltage above your 14.4v cutoff, the longer your flight time will be. The other piece of data to consider is that the 11000mah pack weighs quite a bit more which probably contributed to the average amp draw being 3A higher.

    What I asked him in reply was whether putting two Maxamps 11000 in parallel would improve the situation. Given that the C8 needs to draw 60 Amps, say, then if there are two in parallel then each battery would only need to supply 30 Amps. The parallel setup would still be 40C as I understand it, but C has now doubled to 22000. He's not replied to that yet. I'll keep you posted.

    There is also a suggestion in the first paragraph above of Clint's email that perhaps setting the low voltage threshold at 14.4 volts is a bit too high.

    Andy.
     
  3. Jeff Scholl

    Jeff Scholl Distributor

    Joined:
    Jun 29, 2012
    Messages:
    240
    Likes Received:
    50
    Side note:
    I have all my cutoff's at 14v and the one thing that I've noticed is that our QC lipos brand new will use all of their capactiy by the time they reach 14 volts. On the charger I have seen it take back all the mah back and a bit more. However, after a few months of usage the voltage starts to fall off. When I hit 14v and the lipo takes back only 80% of capacity it gets retired, or a test lipo for quick flights.

    My message here is that with our brand new lipos make sure you are close to your landing spot when the 14v warning shows on your telemetry. Typically I loop every 5 seconds through my voltage telemetry fot the last part of my flight so I'm not stuck way out in the back 40 without any juice.

    One more thing....I often feel naked when I have to fly a customers non-MX-20 platform without my Graupner "British girlfriend" in my ear :)

    Cheers,
    Jeff
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    Hi Jeff: Yeah, I'm with you on the 14v. Too close for comfort for me -- and the 12v Recom for the FPV shuts down pretty quickly if you drop below -- I've only done it as a test when I'm on hover in ground effect just to see what actually happens.

    I think I'd rather stick with a 14.4v warning. I would much cut the flight short by landing than cut the flight short by crashing!

    I also agree with you re: Graupner's Brit GF. I use a small battery powered speaker (Macally for iPod) rather than an earphone -- that way the shooter I'm with can also hear the battery voltage and plan ahead -- they know we go bye-byes when she says "Minimum Input Voltage." at 14.4. I've found that I can be 200-300 yards away and come home with voltage to spare. Even better if the coming home involves a descent, less margin if the C8 is level with me (as it was over a river canyon) so I had to climb to bring it home.

    Andy.
     
  5. Morgan Friedland

    Joined:
    Aug 24, 2012
    Messages:
    84
    Likes Received:
    9

    Two MaxAmps in parallel would discharge at the same rate, but at only half the rate on each battery as the C8 would pull from both, no?
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    That's the suggestion I've emailed to Clint -- the hope being that if the discharge rate is causing a voltage sag, then two in parallel "should work" (as we say in the software business) as the individual discharge rate will now be halved and, hopefully, therefore at a amperage where the voltage will not sag.

    I'll keep you posted.
    Andy.
     
  7. Morgan Friedland

    Joined:
    Aug 24, 2012
    Messages:
    84
    Likes Received:
    9
    Ah yes. Sorry. I didn't read that far back. I have had 2 of these 11000 batteries and was shocked how quickly the voltage dropped. Great company though. I just received a hand written card thanking me for purchasing and not to keep them a secret.

    Morgan
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    Have you tried them in parallel, Morgan? Does that help sustain the voltage? Or will we be putting their return policy to the test? :(

    Andy.
     
  9. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Ok so FINALLY was able to do a test with my Maxamps 11,000mAh battery... I am VERY disappointed! I got a total flight time of 7.07min according to MKTools. I am attaching my GPX file. I was flying in no wind, 5DMKII w/20mm F2.8 lens. Very easy flight. Mostly just hovering around. No crazy movements or ascends/descents. Battery was showing 16.6V on my MX20 when the copter was first powered on. As soon as the motors started the voltage dropped drastically. Within 30 seconds of flying the voltage was reading 14.9V! Once it hit the 14V range the rate of dischared slowed down and I got another 6 1/2 min of flying time out of it before my low voltage warning hit. I have it set at 14v.

    I then grabbed my newest QC6200 and then flew for just under 7min! Looking at the GPX file from both my 11,000 only discharged about 7,200mAh while my 6200 discharged just over 6,700mAh! I will be calling MaxAmps today to get a refund. I am not very happy about this at all. :(

    Josh

    P.S. REMOVE THE .txt FROM THE GPX FILES TO VIEW THEM!!!
     

    Attached Files:

  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    Rats! I was afraid you'd find that, too, Josh. The problem is they advertise "True 40C" -- turns out that, based on talking to a very helpful guy at Maxamps, named Dustin (Clint being out of the office until Monday), that really means "Peak 40C".

    The good news is that they do have a 30-day money back guarantee so that should not be an issue for you (or me). I'm going to wait until I talk to Clint on Monday to ask him:

    1. Does he think there's any merit in trying out two 11000 Lipo in parallel. This puts there internal resistances in parallel and halves the amount of current each has to deliver. (I did order up a second one specifically to try this experiment, but I hesitate to crack the box if I'm going to have to send the battery back.)

    2. Do they make custom Lipo's? (I think the answer might be yes). In which case let's see what they can offer.

    It used to be the "tyranny of the NiCad" that we lived under, now it's the "tyranny of the Lipo." Bummer.

    If you're going to call Maxamps on Monday to get an RMA for your 11000, could you make sure you talk to Clint and mention the FreeFly forum and the fact that you and I have been messaging back and forth. I think they'll be more receptive to a group approach rather than us as individuals.

    Andy.
     
  11. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    Sounds good! I will do that.

    Really sucks that this happened... I was looking forward to having some nice long flight times!

    Josh
     
  12. Nick Kolias

    Nick Kolias Moderator
    Staff Member

    Joined:
    Jul 4, 2012
    Messages:
    140
    Likes Received:
    24
    Wow, I'm really surprised the flight times are that short with those 11000 packs. It doesn't make sense but I'm at a loss to explain it. How heavy are those packs, guys?

    nick
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    I measured it at 1.96 lbs. 0.87 kg if you're into milli-thingies (which I am).

    The problem is that the "True 40C" advertised on the web page is peak discharge, but it comes with a price -- I suspect the internal resistance of the pack is much higher than the QC 6200, so when you pull 60 Amps out of it, the internal resistance causes the voltage to sag.

    I'm calling them on Monday to discuss (a) returning the packs and (b) what else that can suggest for our application. Keep you posted.

    Andy.
     
  14. Nick Kolias

    Nick Kolias Moderator
    Staff Member

    Joined:
    Jul 4, 2012
    Messages:
    140
    Likes Received:
    24
    Cool- will be curious to hear what they tell you.
     
  15. SteveWilson

    SteveWilson Member

    Joined:
    Sep 29, 2012
    Messages:
    63
    Likes Received:
    4

    I don't have any experience with these 11,000s, but we do have some 8000 Thunder Powers and we found that the meat of the power comes at a much lower voltage. It's a little nerve racking at first, but I think you need to fly it beyond 14v. We all know how quickly a regular lipo drops from say 14.5 to 14, well we found that doesn't happen with the big battery. If you are up for it, bring your machine into a hover a few feet off the ground and run those batteries down to 13.5v and I bet you'll find a bunch of the extra power you expect these batteries to have.
     
  16. Josh Lambeth

    Josh Lambeth Well-Known Member

    Joined:
    Jun 29, 2012
    Messages:
    1,313
    Likes Received:
    214
    I might have to give that a try... I noticed that once I shut down the motors the voltage was back up to around 15.1V.

    Andy I am flying out to Denver this week and won't have the battery with me. Are you able to perform this test soon? I may hold off on calling Max Amps today if you are able to do this test. Thanks!

    josh
     
  17. Nick Kolias

    Nick Kolias Moderator
    Staff Member

    Joined:
    Jul 4, 2012
    Messages:
    140
    Likes Received:
    24
    Does Adele know about this? :D

    What about those 8000mAh packs you were trying out this summer? How did those do?

    nick
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    Oh....I've packed both 11000s up ready to go back. Let me call Clint and talk to him first. Keep you posted.
    Andy.
     
  19. Jeff Scholl

    Jeff Scholl Distributor

    Joined:
    Jun 29, 2012
    Messages:
    240
    Likes Received:
    50
    Adele is going to get a british voice also in the future :)

    The 8000's are still going strong. They have been kicked around the block a bunch and they still take 7400ish on charge.

    Cheers,
    Jeff
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,377
    Likes Received:
    1,162
    [Edit: I have made some corrections in red to this posting]

    I spoke with Clint at Maxamps. You can reach him at 888-654-4450 (they're in Spokane, WA, Pacific Time Zone) or clint@maxamps.com.
    He is quite happy to allow me to return the two Maxamps 11000 for a refund, so go ahead and give him a call/email, Josh.

    They can make up custom batteries for Cinestars/heavy lifters.
    He suggested one of two batteries based on your choice of weight/cost.
    9000 mAH, 4S, 862 grams, $250, 40-50C continuous, 80-100C burst. 162mm x 45mm x 50mm
    10900 mAH, 4S, 919 grams, $310, also 50-60C continuous, 100-120C burst. 137mm x 45mm x 69mm

    Both packs are custom made to order, so you can expect 1-2 days lead time. You can specify whether you want Deans or EC5 connectors.
    They also sell the Hyperion EC5 charging connectors and can make up EC5 Y-cables for using two packs in parallel.

    I forgot to get the physical dimensions of the two packs -- I've emailed him and I'll update this posting with that information when I get it.This posting has been updated with the physical dimensions.

    Don't hesitate to call or email Clint if you have specific questions.

    Thanks
    Andy.
     
    Jon F. likes this.

Share This Page