Im needing to buy some more. What are you guys flying? I am wanting to stay with a 4S setup since the 5s setup runs hotter... I don't want to run any hotter then I already am. THanks! Josh
QC6200's. I'm going to start putting bundling them in parallel pairs. I've got Maxamps 11000 -- haven't had a chance to test fly it yet. Andy.
Thunder Power 4S 45C 6600mAh packs. Run two in parallel. They have been outstanding performers so far. nick
Just ordered one of the 11,000mAh batteries from MaxAmps. Funny too, they are out of Spokane WA which is where I am from! Josh
I'm on the cheap side Zippy 8000 and Nanotechs 6000, both 4S.... they are "honest" for the price but don't have a long life span. I have to replace mines every 4-6 months, but I really don't take a good care on them, sometimes I have to charge them on a hurry on hot locations, and this is a death sentence for any battery, and that's the main reason I went for the low priced side. BTW: Flight times => CS8 + 2 Axis + 5D MKIII + 20mm = a little over 7 min with 8A and around 6 min with the 6A
Arthur: How are you measuring your flying time? Takeoff to landing -- what voltage do you have at landing? (As a supplementary question, what you set your low voltage alarm to? I have mine set at 14.4v just to give time for "come home" and "land." Andy.
Hi Andy, I have my timer set to the Throttle stick, when it's over 5% it's running, when I get below that it stops. So it's like take off to land plus 10s (gyro calibrations and pre-flight check). I have my FC alert programed at 13.8 (if I remember right) but I almost never hit this alert. I'm using the TM1000 (Spektrum telemetry module) connected to the Power Dist board and my DX8 is programed to vibe at 14v. So when the TX start vibrating I know I have at most 1 minute, and if the leds and buzzer start to blink and beep it's a "get out the way" landing approach With this config I have just like a car gas alert, low fuel before empty.
Thanks, Arthur. I think I'm going to do some systematic measurements of flight times using the following protocol: 1. Weigh the aircraft, battery and camera. 2. Take off and hover at about three meters above the take-off point. Timer start on take off. 3. Enable altitude hold and GPS hold. 4. Time until the battery voltage reaches 14.4. 5. Time until the battery voltage drops to the point that I lose the video downlink (the DC/DC 12 volt converter has insufficient input voltage). 6. Land. I'm curious to see how a single 6200, a dual 6200, and a single Maxamps 11000 stack up. I might even invest in an additional Maxamps 11000 if the data suggests it might be worthwhile. Andy.
I would be interested in that test as well. I am excited to get my 11,000mAh battery! Hoping to have it next week! Josh
Desire power 10800 4s singel (920gram), super performance and very low resistance/cell and no magnetic errors.
Andy - a couple weeks ago we did some similar testing with a host of parameters (temp, elev, humidity, DA, gross weight, batt. type/weight, etc.). We haven't had a chance to sift through the data yet, but our intent is to develop some usable graphs that identify probable flight times under various configurations/payloads and density altitudes. We'll post the data once we process through it. As you've suggested, replicable flights (i.e. hovering at 3 meters) are the only true way to test and compare. Hovering out of ground effect uses the most power, whereas directional flight between say 5 and 15kts is far more efficient due to translational lift. However as long as each flight in the test is roughly identical, you should yeild reliable results.
Thanks for the comments, Jon. In my case, my test site is pretty much at sea level and the temperature forecast is for the 70s, so density altitude should not be too much of a factor. I'll record that information anyway so that you can, if you choose to use my data, normalize it for standard atmosphere. Not quite sure how I can best get the air pressure (QFE to Brits) -- may have to rely on PDX ATIS. A key question for me is, given a LiPo of X mAH and Y grams, what is the likely flight endurance increase if you fly with two such batteries in parallel -- 2X mAH, and 2Y grams. Does one see endurance factors of say, 1.8 (purely speculative) over the single LiPo or what? Clearly, if one is flying a Red Epic, there is merit in using double batteries just to reduce the risk of a LiPo failure (how often does that actually happen, I wonder?) Andy.
I think you'll find it interesting. On my Cinestar, very roughly, one 5000 mAh, 4s gives about 5 minutes and 4 of them in parallel give right around 18 minutes. So not linear, but pretty good. Most I've run is 4 - 6500 mAh and the same percentages seem to hold.
Indeed interesting Steve. You could probably plot a curve showing one to four batteries and the flight times. It's surprisingly efficient given the linear increase in weight. Andy.
DANG! I just checked the shipping info on my MaxAmps 11,000mAh battery and it will be here tomorrow! Thats only 3 days from the time I ordered till when it gets here! AWESOME!!! Can't wait to go fly it! Josh
Andy, it certainly could be beneficial to have pressure reading for testing. The ATIS should have the altimeter setting and maybe DA as well. We have a simple spreadsheet that I could share with you for recording flight tests if you like. I'll also send you our test results once we compile them. On the second part, we also had the same question: is added flight time justified by added weight? We thought we were going to see mediocre endurance numbers due to added weight of an extra lipo, but we only saw a small proportional decrease in flight time. (i.e. if 1 lipo flight time was 4 min, then 2 lipos were 7:30....as a very rough example) One of our best results came from flying (2) Thunderpower 4s 5400's in parallel - for us at our elevations, this is just the right endurance to weight ratio. The difference for us comes at the extreme high DA's, like 12-14,000', where adding a second lipo reduced the power margin (burst) to nil. Just not enough for the blades to bite. Kinda unnerving.
Sure, if you could email me your empty spreadsheet: ajohnsonlaird AT me.com that would be great and I'll add my results and send it back you you. Interesting that the "efficiency" of adding an extra LiPo is so high. I would have expected more rapidly diminishing returns. DA's like 12-14000 are scary in their own right....makes one wonder what size/pitch props you need to spin to get enough air mass chucked downwards.... Andy.
I use thunderpower 65C 6600, and get a good 7-8 minutes with CS8, 360 and CX760. No more puffed packs like I used to get with the QC 6200's. Josh, I can't wait to hear about these Maxamps....sounds unbelievable.
Well, sadly, it looks like the Maxamps 11000 may not be the way to go. The flight times are no longer than the QC6200. Clint at Maxamps was kind enough to respond to an email I sent him. The issue is this: the Maxamps 11000 is only rated for a 40C discharge rate -- pull more current out of it than that (and the Cinestar 8's certainly do), and you discover that the voltage sags. In contrast the QC6200 is rated 25C continuous, 50C burst -- which is why it delivers the power that it does. It's that 50C (and the implied lower internal resistance, I suspect), that makes the QC6200 a superior battery for our purposes. Of course, that does raise the question, so what happens if you put two Maxamps 11000 in parallel? [Edit: Duh. Sorry. The discharge rate would still be 40C, but the capacity has now doubled to 22000, so the effect is to increase the discharge current.] Josh: What did you find with your test flying of the Maxamps 11000? Andy.