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View Full Version : bl motor cuts off at 2/3 wot


ericthetree
10-12-2005, 07:38 PM
I am using a 2cell lipo,will it stop cutting off if I go to a 3cell. Motor- 5400kv w/20mm case - swinging a 4 5/16 x 5 prop, CC phoenix 25

Mike Parsons
10-12-2005, 08:27 PM
Eric,
Two things could be happening here
1- Your CC-25 Low voltage cut-off is set for three cells (9 volts) and not two (6 volts). When you go above 2/3 throttle if the battery is sagging, it could be tripping LVC.

2) You are overamping the CC-25 and causing it to shutdown. (not sure what kind of amperage that prop pulls, but I doubt it is more than 25)

Increasing to a 3 cell will give you more voltage, but wont necessary fix the problem unless your 2 cell pack is bad and or #1 comes into play.

I would check the LVC programming on the CC-25 first.

-Mike

ericthetree
10-12-2005, 09:26 PM
thank you Mike. I reprogrammed esc to 6volt cutoff and it improved but still can't go WOT. It must be trying to draw too many amps from battery. bearing in mind that I know almost nothing of these matters.

watt_the?!
10-12-2005, 10:07 PM
interesting...that setup should be no more than 20A at WOT. Is it the 2015-5400 you are using?

try setting your radio to another virgin model and test. I've seen the throttle cutoff on Txs do this once or twice before, only to not display it on another model on the Tx.

Tim.

oh, what capacity lipo are you using?

ericthetree
10-12-2005, 10:40 PM
I'm not sure of motor specifics, all I know is that it is a GULI / 20mm case and is supposed to be 5400kv. I am using 1300mah 2 cell lipo.

Mike Parsons
10-13-2005, 01:19 AM
Just ran the setup through Mojocalc with the 2015-5400. It is stating 17 amps at full. That is 14C that is being asked of that pack. That is most likely the problem. Even a 10-12 C pack would sag under those conditions. What pack is the 1300 (brand and C rating if you know it)?

ericthetree
10-13-2005, 03:03 AM
I'll have to pick up a stronger pack.what would you use? Did it say what the thrust would be?

Dr Kiwi
10-13-2005, 12:45 PM
You probably need something like a ProLite TP 2100/Tanic 2200 etc to ensure decent voltage at 17A-20A under load.

Here is what Motocalc says:
Motor: HiMaxx HA2015-5400; 5400rpm/V; 1A no-load; 0.12 Ohms.
Battery: Thunder Power Pro Lite 2000; 2 cells; 2000mAh @ 3.7V; 0.007 Ohms/cell.
Speed Control: Castle Creations Phoenix 25; 0.0065 Ohms; High rate.
Drive System: Direct; 4.3x5 (Pconst=1.06; Tconst=0.995) direct drive.
Airframe: Anything you want.
Motor Amps = 18.5
Motor Volts = 7.0
Input (W) = 129.7
Prop RPM = 21518
Thrust (oz) = 7.4
PSpd (mph) = 101.9

The worrying thing to me, is that if you do have a Himaxx 2015-5400, it is rated at only 15A max!

Cheers, Phil