|Dec 29, 2001, 10:43 AM|
MM Zagi Battery Comparison
For those interested:
I timed my MM Zagi flights today. Here are the results:
MM / 6x5 Aeronaut Prop / KR1400AE x 8 = 5:45 Full throttle
Same Motor/Prop / SunPac 1600 NiMh x 10 (Cheapos I got off Ebay for $1.50 ea) = 5:50 Full throttle.
KR1400s = 4:18 / 19.7 Amps
Sanyo 1600 NiMh = 6:00 / 16.3 Amps (Not the same batteries but all Motocalc has)
Each flight was flown until power was down to where I could no longer maintain level flight, but the BEC had not cut the motor off yet.
- The 10 cell NiMh give a little more performance for the first minute or so but then drop down to about the same as the NiCds.
- I don't have a scale, but I am sure the NiMh are heavier and I like the flight characteristics of the lighter weight better.
- The NiMh are much hotter at the end of the flight, so I doubt they will last as long.
- I paid $24 for a built 8 cell pack NiCd with Deans connectors. I paid about $19.50 for the materials to make my own 10 cell NiMh pack with Deans connectors and shrink wrap.
- For the extra five dollars, I will buy the KR1400 pack for my MM Zagi and save myself the time of building battery packs.
I have not tried any other batteries (CP1300s, etc) I would like to here your results.
|Dec 29, 2001, 02:15 PM|
I typically fly mine on a 10xCP1700 with a 7x5 prop. Heavy, but I find it well worth the weight, it's impressive. I've flown the 10xCP1300SCR as well and while it's certainly acceptable, it doesn't compare to the 1700 pack in terms of raw power. No numbers for you yet, just a gut feeling from flying it. I'm guessing at least 5 minutes on both packs.
As soon as I get my 3C done (Monday?) , I'll be able to do full throttle and get some accurate numbers. My current flyable MM Zagi is prone to the flap these days at full throttle with the 1700's.
|Dec 29, 2001, 04:24 PM|
I failed to mention that mine is chopped down to 35 inches. I am not sure how much more weight I can add to this thing.
Can you tell me why the CP1700s have more power then the CP1300s? I was under the impression that all of the AE batteries had the same amount of internal resistance and therefore power, and I thought all of the CP cells were the same on resistance and power.
|Dec 29, 2001, 05:04 PM|
I have no idea why the 1700's perform better. Without any hard numbers to give you yet it might be all in my head. According to the Sanyo database, they are both 4mOhm's, but Magellan Tech says at 1000Hz the 1300 is 7.8mOhm while the 1700 is 4.7mOhm which would support what I see in the field.
I originally ordered the 1700 for a TJ and it wound up in my MM Zagi.
FYI: I just weighed my two packs with Deans Ultra connectors on them and came up with:
10x1300: 12.8oz (364g)
10x1700: 16.5oz (469g)
Both of those came from www.eflightpacks.com
|Dec 29, 2001, 05:34 PM|
How does the motor hold up to 10 cells direct drive? I use 8x800ar with my MM powered Zagi and the 6.5x4 areonaut prop. It performs great with that setup, but 10 cells must really make it go. How long would the MM last with 10 cells? I fly with full thottle most of the time!
|Dec 29, 2001, 05:51 PM|
It seemed to hold up quite well. After about 20 flights, I put ball bearings in it (30 minute job) and did at least another 10 on it. I had to reset my flight counter though since I had to put a new motor in last night after this revengeful psychotic light pole sucked it into the concrete base during a landing. (It's been trying to do that all winter. I must have pissed it off or something.) It broke the end bell housing so I'll use it for spare parts now. I did get into the habit of putting a drop of good bearing oil on the bushings every 5 flights. I found the oil at tower hobbies, it's made by Trinity I believe.
Flyinryan said that his lasted about 25 flights full bore. http://www.rcgroups.com/forums/showt...threadid=17476
The ball bearing conversion is easy once you do one and I would highly recommend it for abusing your Zagi. Instructions can be found here http://marcee.20m.com/Articles/MagneticMayhem.html
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