Got a problem with my brushless setup

[Quicksilver]

Hey, new here, but I'm sure many know of me.

If not I converted a Villain IV into a jet boat with a 700sc motor, tekin marine 432m esc and 12 cells.

I just switched to a feigoa 12L and decided to use the SV27 esc. Since it seemed to fit the amp rating on the esc and motor. I'm using a graupner jet drive, with a 29mm impeller.

Well, it doesnt work, I plug the batteries in, turn the radio on, put it to full throttle, get one beep, I return to neutral and get 5 quick beeps. If I slowly advance the throttle, she'll fully rev up. However if I push the throttle quick she quits before maybe 5,000rpm. As soon as I put the boat in the water and hit the throttle in any manner, it quits, immediatly.

I havent a clue, the shaft spins freely, I used gold connectors for the motor to the esc. My batteries though a modified sport pack of NiMH 2400Mah cells, are put together with deans bars and 12gauge wire. I'm using a so far very reliable Futuba ATTACK SR stick type radio.
The motor is rated for a max of 51amps. and the esc is rated for 45amp, pretty close. My 700sc never got past warm after a 7-8 minute run on the 2400's. Figured maybe that motor pulled 20amps average.

Anyways I know thats a lot to read, but I'm new to brushless, but not to this boat.
I'm also a very loyal customer. :)

Greg

p.s. a video showing the trouble in a test is uploading. you'll see when ever the motor gets a load, it quits.

[Jeepers]

sounds like your radio is the problem, most marine controlers are designed for a pistol radio, especially the SV controler. IMO i would use a higher amp rated speed contol for that motor and the jet drive. jet drives have more load on the impeller as they are fully submerged.

[Quicksilver]

I am interested in this radio problem, usually people have the opposite problem.

I think you should at least see the video. Maybe it's not ideal, but this is quite the problem. I hope it the radio, they're cheap. This boat does cavitate quite a bit. Unitl my video is processed . Here's some old videos, she moved, you can also see the water is pretty aerated. I actually tried tossing the boat today.....nada

http://www.youtube.com/watch?v=xtTBP6cuVf8

http://www.youtube.com/watch?v=9jhef3-jjvE

[saleens7]

i would use an esc that has has an amp rating more than the motor...just saying, if you ever get something caught up in the impeller, that will make the motor pull some serious amps, you might as well say goodby to your esc...also, it is meant for a pistol radio, so i would suggest you get one...i dont know if im right or not, but does the sv27 esc need to be programmed?

good to see ya over here quicksilver, hope you figure out the problem....

[Quicksilver]

Alright, not liking the consensus, I can totally understand the radio problem, though I dont see how it would lead to this weird cut off. It's funny saleens, if you remember that thread about bad advice and here I was given two very bad pieces of advice, unless something else is wrong. Wasnt you obviously, but people who should have known better.

If this video ever uploads.

http://www.youtube.com/watch?v=GUe1ISs4G5Q

[saleens7]

i dont think i remember that thread........ futaba radios are kind of strange...you have to mess with the throttle settings alot and most of the time and it needs to be reversed before the esc even responds to it....i think the esc may be shutting down on you when you throttle up becuase when it winds up the prop it will be putting alot of strain on the motor and may have more amp draw than the esc can handle...just a suggestion...im not familiar with the sv esc, so i could be wrong...

[Quicksilver]

well, I'm pretty much convinced I should get out while the gettings not as bad as it could end up.

Gonna have to fork out more money for the jeti esc and hope my 700sc isnt fried. Perhaps that's something Steve could answer me. Basically if I blow my diode, remove it and it still runs fine when directly connected to a battery, can I just put a new diode in it, or could something be wrong still.

Anyone want a barely used SV27 esc or a barely used feigao? :) :)

[Doozie870]

What motor how many cells were used in the old video? that is really neat.

[Quicksilver]

the 700sc on 12 cells

[Doozie870]

Why do you think the sc is fried?

[Quicksilver]

to quote myself

"Alright, I've got to ask for help on this one. I spent much of the day prepping the boat to run 16cell with a new impeller. So I get to the lake, turn the boat on, test the throttle and I get about 50rpms, basically barely turning and twitchy. I figure it must be the esc....couldnt find anything wrong, so I packed up and went home.

This is where it gets interesting. I test for shorts can't find any problems, that I know of, I test the output voltage on the esc, getting 20v off the 16cells. Ok, so I hook up a 550 motor to the esc, runs fine. Now for the kicker I decide to plug my 700sc directly into a 7cell pack, seemed like the next logical step.....well poof tons of smoke. One of the diodes melts and one pole of the motor gets real hot. Now, I figure maybe it's the lube I'm using (white lithium), so I make sure nothing on the motor that shouldnt have greese doesnt and I pull all the little diode wires and such out of the way, to make sure theyre not hitting the can. So again I hook the motor up to the esc, but only on 7 cells. Again instant smoke. from the inside of the can.

Now, I'm guessing the motor is shot, but why would this happen? It ran perfectly fine last time I ran her on 12 cells, I want to blame me having upped the voltage but since it never even revved up period I dont know what to think. I looked at the brushes, theyre heavily grooved but have a lot of meat still on them.

mind you the 700sc is rated for 6-16 cells.
and my esc is rated for up to 30+ cells.
and the motor turns freely."
--------------------------------
later on

"Well thank you. It's not over yet but there was like a herd of gremlins today.

After consulting a fellow member over this, I've come to the conclusion that I had a bad "weld" on one of my battery packs, which I hadnt realized for some time. Something happened a few weeks ago that couldnt be explained till now. The boat had gone dead completely for about 5 seconds and then worked fine again. This was when that weld went. I've run the boat 4 times since.

So I figure the voltage irregularities led my esc to fail, causing the motor to blow along with its diode. The motor may or may not be completely fried, however if I need to buy a new esc, I might as well dump the 700sc(great motor though) and buy an esc for my feigoa motor which I still havent used. Same time, new packs are in order. Learned a valuable albeit expensive lesson. I may bite the bullet and buy an esc tonite.

As far as batteries, if anyone knows of any great deals on good pre-built packs let me know. I doubt my soldering skills anymore, if things couldnt have gone worse I actually broke my soldering iron just now fixing the broken pack.

p.s. this was one of those day where I should have seen the signs, I should never have run her and I'd explain but it's complicated, I knew something very bad was going to happen today and I kept getting reminded till it happened."
----------------------

so yeah I took the esc apart and one of the fets must be shot. it gets so hot it burnt me after maybe a minute of being plugged in to the packs.

So yeah, I'm going to get the jeti navy esc and go back to the basicas again
If you want to see more videos, being I've filmed a ton heres my channel or what ever you call it.

http://www.youtube.com/profile?user=quicksiler

[Jeepers]

I JUST NOW thought of something. If my memory is correct the SV motor is a 6 pole motor, The 12L is a 2 pole motor, the esc is probably not programed for a 2 pole motor. I have to program my mgm esc to run a 4 pole NEU motor and I remember that it had different settings for 2 or 4 pole motors. how to program the SV esc I have no idea, but this might be your problem also.

[Quicksilver]

Well I think it may be okay, I cut the schtocky sp? diode off the motor and she runs fine hooked directly to a 6 cell pack. So I figure, new diode and new esc and maybe things will be okay.
The esc is definitely gone, what a shame, nice esc, served me well for 11 years on 4 boats.
If you're interested in other videos, I've got a tons.

http://www.youtube.com/profile?user=quicksiler

[Quicksilver]

oh, I missed your reply, we posted at the same time.

see that makes the most sense, it explains the true peculiarity of the problem. So theyre not compatible.....period. you cannot plug anything into a SV esc as far as I can tell, unless you tore it apart or something.

[ED66677]

tell you what... get a cheap 80amp Mystery BL ESC on Ebay (50$ max) plug it to your 12L bl and give it a try with the PiStix adapter 'cause Mystery is mainly design for plane, I've got one one my 8XL running very well @ 76amps peak 68 constant!