rhampton

My Feedback: (66)

OK I NEED SOME EXPLANATION HERE.....PLEASE HELP

ok i purchased a Mystery Pentium 80a esc from ebay for $9. here's the Link.
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT

ok let me explain this slowly.
im Flying a Yak with a 64" WS and im using a Roxxy motor that Swings a 18x8 Prop and im using a 6s 3300mah 20c Lipo.
My 1st 3 flights were successful with no problems. 4th Flight i would here a noise from dead stick to throttle. My brake was defaulted to on from factory even tho package shows that by default it was off. Another words when my throttle stick is all the way down, my prop completely STOPS. So i would go from dead stick back to mid stick and i would do that periodically during flight. Well i notice that about 1 minute into my flight i went to dead stick and then my motor would not come back on. so i had a minor hard landing. Nothing major and no damage for i was lucky, but when i landed i noticed the motor was working again, so im assuming this had something to do with esc. Does anyone have any idea why it would cut off liek that? i could have had a dangerous landing. When i purchased this 80a esc....the AD shows input voltage as 5v - 26v and actual esc shows 2-6s Lipo. but when i looked on various rcgroups forums on the manual for this esc it only shows Li-ion 2-5s and no where does it show 5v-26v. So now im confused as to weather this esc can take a 6s. Can anyone shed some light on this. Did it cut off because i was going from dead stick to throttle a lot? or did it cut off cause i was using wrong cell count.

Walt Thyng

My Feedback: (9)

Sound like you were hitting low voltage cutoff. If you don't have a manual, go to the Mystery web site and downlaod one.
Walt

b16a2sir

My Feedback: (3)

I have a 45A, 2x 60A and a 100A mystery ESC. I have used 6 cell on all of them except the 45A(havent used it yet)

I do think you ONLY want the brake on with a folding prop. These ESC's can be programmed, and maybe with your motor (i am not familiar with) you may need to change timing or PWM.

Also, are you using a timer on your Tx. I wouldn't expect you to get much more than 4min on your setup. The prop sounds quite large, so I expect your motor to be low kv (400 or less).

could be a few things, does the ESC still work? does it smell burnt at all. On your last flight, how warm was it? does your motor heat up? Could there be any contaminants in the motor? all connections are secure and solid?

rhampton

My Feedback: (66)

yes my Motor is a low KV. i believe it's like 537. I set my timer on my TX to 4 minutes and no that particular esc doesnt seem to get how after my normal flights. However at THAT time i had my incident i didnt check it. I gave up on using a 6s on that esc so i am now using this 80a on a smaller plane that requires a 4s setup and so far so good. Flown like 5 times and no problems. i guess the cheaper esc's cannot be taken to it's limit. One thing i learned about the more cheaper ones is to use it well below it's Maximum capability. if it shows 2 to 6s. Only use 5s or under. When you use it to it's max is when you start experiencing problems. If i programmed it like you suggested, i may have been successful but i gave up to fast. Maybe i probably need to invest in a more better quality esc for my bigger planes like a Castle Creations 80a HV or something.

Walt Thyng

My Feedback: (9)

rh: this may be an example of the 80% rule which seems to be especially applicable to lower cost e-power equipment. Never plan on using more than 80% of the stated parameter (amps, mah, Kv etc). Another way to look at it with escs is to use the max continuous amps as the burst (short time) limit and 80% of that as the max continuous. Same goes for the number of cells an esc is claimed to handle.
Walt

flytreetimes

At 537KV the 18/8 is grossly overproped, should be more like a 15/8 at that KV and even that would be pushing it on ^S. I would think the 18" would be well over 80 amps, so it could have been a thermal shutdown (overtemp) or like someone suggested you hit low voltage cutoff.
Always use no brake unless you have folding prop, harder on the motor. FWIWflytreetimes