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Aug 01, 2001, 10:18 PM
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Ben74's Avatar

Sanyo 720mah NiMH max current drain?


anyone know the max practical current drain that can be put on the sanyo 720 mah NiMHs? are they ok for s400 use?

thanks,
ben
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Aug 01, 2001, 10:49 PM
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Andy W's Avatar
No! About 6A or so..
..a
Aug 02, 2001, 03:08 AM
EDF Head
Haldor's Avatar
They drop down to ~1V/cell at 3A load but can take 5A short time. As Andy said no go on s400's.

The smallest NiHM for s400 would be ~1000mAh cells and keep the current at 8A or less. (= gearbox)
Aug 02, 2001, 02:02 PM
Registered User
Andy W's Avatar
I guess the confusion is that most of us run speed 400's near their operating limit. That is 10A and above. If you're well below that, which I undestand the Hawk is, they may work OK. Just don't exceed 4-6A..
..a
Aug 02, 2001, 02:14 PM
Registered User
The Wattage Hawk uses a 7.2 volt Speed 400 motor and 5.5x2.5 prop to keep the amp draw down. This combo flies the heck out of that little bugger though and does allow for the use of nimh cells which give the benefit of less weight and excellent duration. I'll bet you could get away with a 6x3 prop as well for even more omph. I'm planning on using the above combo in an Elipstik. It would probably work pretty well in a lightweight pylon/sport ship like the Flea or Bare Bones if you wanted longer flights albeit with less performance.

Greg



[This message has been edited by greg morrison (edited 08-02-2001).]
Aug 02, 2001, 02:56 PM
Superhero, Third Class
astroboy's Avatar
I tried the 5x2.5 that comes with the Hawk on a 6V 400 and an 8-cell, 1 amp nicad pack. It drew 9.8 amps, static.
Aug 02, 2001, 03:20 PM
Registered User
Bill Glover's Avatar
I've used 7x720 nimhs at 7.4A (S280BB direct drive on 4.7x2.3 prop). They didn't get much more than warm at this current, but I don't think they were operating very efficiently! The current shot up to 11.4A when I substituted 500ARs, and I had to go down to 6 cells to keep within the ESC rating.
Aug 02, 2001, 08:23 PM
modest-master's Avatar
My Speed 280BB 3.5/1 MP-Jet gearbox/APC 10x7 almost 11A the 720mAh NiMH no problems at all. I have been flying for 10 monts with this set up. The packs are still good and alive.
Speed 400/Gunter prop full throttle 13A.
Speed 480/APC E5.5x4.5 prop full throttle 10A
Aug 03, 2001, 12:52 AM
Registered User
Ben74's Avatar
hmm. i'm sort of surprised to hear that. i have one 8 cell pack of 720 NiMHs that i originally bought for a 280 plane, but have been using it in my Wattage Hawk, and a s400 glider with good results. the Hawk goes like a bullet, and the glider performs well too. the battery never seems to get that hot. maybe because i'm giving it good ventilation. i hope i don't ruin it by using it this way.