Aquacraft Wildcat Cat Question

[gener88650]

Hi Folks,
New member here so be gentle...

Bought a Wildcat (26.5 inch one) minus speed control and motor on scratch & dent. Stock it had an 1800kv outrunner and a 50 amp esc so I went to HK and got these:

1800 kv outrunner
http://www.hobbyking.com/hobbyking/store/__21480__NTM_Prop_Drive_28_36_1800KV_438W.html

50 amp water cooled esc
http://www.hobbyking.com/hobbyking/store/__24568__HobbyKing_50A_Boat_ESC_3A_UBEC.html

So, I install all and use a 3 cell 2200 lipo and all is well for about 3 minutes. Good speed and boat handles well.

Then, all stops and esc is burned out. Plug in and initializes (beeps 3 times, then nothing).

So, any speculation on post mortem? Could this combo pull more than 50 amps? Is the speed control over rated?
Should I have used capacitors?

I got a spare esc and I could try that but I do not want to fry it too doing something stupid. I have a watt meter but that only works in my hand so I cannot see what the current draw is on the water.

Sorry for the long post, any help appreciated.

Thanks
Gene

[gsbuickman]

Hi Gene, welcome to OSE :tiphat:

For starters, do you have any pictures of your boat,, so we can see the way you have it setup inside, as well as how you have it setup with the prop, strut & rudder ?.
What prop are you running ?.

As for the 50A ESC, that's not going to cut it obviously., and neither is the 2200mah 3s battery, if its 15-25c discharge rating, however a 2200mah won't last long in a boat (maybe 2-3 minutes) before you hit the lvc (low voltage cutoff).

The 1800kv motor is a great motor to start with, its also potent and reliable when used with a proven motor / prop / ESC combination. At a minimum in pretty much any single motor cat/hydro like this, i would run 2, 2s 5000mah 30-40c batteries for reliable power during a run.

Since you need to upgrade your ESC, I would go ahead and pick up a decent 120 - 180A esc, kike the turnigy 120-180A marine,or a 200A Hobbyking ESC which may be a Lil' overkill, but still a great price. If you do pickup the 200A hobbyking opto, it will need a 6v nimh eciever battery as well because it doesn't have a bec in it. A 2000 - 3000mah hump or flat pack will cover you for a 4-5 min. run w/o going dead.

Here's a nice Lil wildcat ep. On a 2200mah 3s w/ a 42mm graupner I like

http://m.youtube.com/watch?v=XamWkPaMwiI
I know you have more questions, l et us hear them. G'night :tiphat:

[tlandauer]

Welcome Gene!
My opinion is that you need a better ESC, at more than 3x the price, this will last more than three times longer.
http://www.offshoreelectrics.com/proddetail.php?prod=ker-seaking-120
I had a 1800kv out runner similar to yours and used in a 24" mono, I used this:http://www.offshoreelectrics.com/proddetail.php?prod=ker-seaking-60 and proved reliable. Spend a bit more and you can use this 120A ESC later for other boats.

[TheShaughnessy]

Ok don't listen to the first post. He linked to full carbon fiber boat that was built up to run on 6s. The wildcat is NOT a 6s boat, it's a plastic hull and will self destruct when it blows over if on 6s power.

Does the motor you have now spin freely? If so try your other esc with it to make sure it is indeed the esc and not your rx or battery.

I'm guessing you don't want to buy $300 worth of electronics and batteries to put in a $200 boat is that right?

As t launder suggested the 60 amp unit from seaking is a well trusted and should be fine for your application, however the 120 isn't much larger phsically and gives you more options down the road.


What coupler are you using btw. The stock one shouldn't have fit on the motor you ordered.

The 3s pack is fine, you could step up to a higher Mah as long as it still fits, but I see no reason you can't use the battery you have now.

[gsbuickman]

My original post was late last night (well after bedtime) and I was having coffee withdrawals :frusty:, and I was thinking of a different cat hull for some reason, my bad. I edited my post the way I wanted It now that i've got my coffee fix on :thumbup: .

[gener88650]

Wow,
Thanks guys. I got the boat with radio (without motor and esc) for $80. I am a long time airplane guy and wanted something that floats...
The motor spins freely (except for the obvious magnet cogging and I tried a 45 amp airplane esc last night and it works so I am certain that the problem is the 50 amp speed control.

I will get one of the speed controls listed. I like the idea of the 120 but I will have to measure the area in the boat to make sure there is enough space. The 120 and the 60 both seem to be the same size. The motor had a 1/8 inch shaft (3.17) and the old coupler slipped right on.

Even after the flame out everything was cool and the water was exiting the side of the boat so the water cooling system must have been working. Not sure how you measure the current? Would having a helper hold the boat in the water with the wattmeter connected give an idea, or do you have to use some sort of logger? Obviously the unloading of the prop as the boat moves would be different.

Thanks again,

Gene