200a ESC won't take WOT

[fenalx]

Hi,

I am using a water cooled Skywing 200a ESC, with a 2760kv Feisuda motor, driving a prather 220 prop in a 32" mono, running on 4s 5ah lipos.

All runs well as long as i don't go full throttle. When i go WOT, there is a cuttoff of power.

Considering motor is rated as drawing max 70amps, can you please suggest what might be wrong?

Am i overpropped?

Thanks

[domwilson]

Sounds like it. Also you may have too high a kv for 4s. Not familiar with that brand of motor.

[ED66677]

agree! such a high kv would be appropriate for a 25" boat but not a 32" one!

[Simon.O.]

That motor is about the same as a 6XL I use one in my 4S rigger but would not have it anywhere near my 30" mono. That is bad enough with a 7XL 2382kv on 4S

I am not familiar with the prather props but I can reccomend that you seriously look at a lower kv motor. While you are doing that I would look at 6S for a 32" mono.
My 30" Balsa mono is on the edge for 4S power.

That 2760kv Feisuda motor would go well in a rigger or hydro. Send it here and I'll let you know how it goes.

I do not think anything is wrong with your esc, there will be soon if you keep at it with that setup.

I have run the numbers on FEcalc, I know that it is not the best of programs but it gives good ballpark figures and allows comparisons of setups.
At present you are looking at over 220A draw on that setup.
That is not good.......at all !!

Even if FECalc is off by 20% you are still at or near 180A on a 200A esc which is all you can ask of an esc, especially a Skywing, Hobbywing, Himodel, Mystery or Turnigy. (they are all pretty much the same beast)

Lower the kv and up the volts. Always a good recipe.

[fenalx]

Thanks for your detailed replies.

To be more specific, i own one of the 32" deep vee ARTR with motor and ESC racing spec of head of the river.

http://cgi.ebay.com/32-deep-vee-ARTR-with-motor-and-ESC-racing-spec_W0QQitemZ290309669369QQcmdZViewItemQQptZRadio_Control_Vehicles?hash=item4397ce01f9&_trksid=p4634.c0.m14.l1262

Since the 2760kv motor came supplied with the boat, i never thought of changing it. I already smoked the ESC that comes stock with the boat, and another 200a esc in this boat (with water cooling). This is my second 200a esc, with an ETTI water cooling plate, and i do not wish to smoke this ESC too.

Should a Feigao 540 XL 10 @ 1668 kv do the job for this boat, or should i go even lower kv?

Many thanks for your help

[ED66677]

the 10XL will not give enough rpm's under 4S I would then go for 5S, but under 4S a 9XL is more appropriate for such a big hull, 4s means high amp on a 32" mono!!!

[NorthernBoater]

Can you be more specific about the batteries?

[ED66677]

you want to have the prop at 30-35000rpm, 10XL under 4S gives 4x3.7x1668=24700rpm unloaded, unders 5S around 30900rpm
if he wants to stay with 4S then the 9XL (1853KV) will give 27500rpm, in fact the 8XL gives a better rpm but will not be able to spin a big enough prop, the 9XL will certainly! too small of a prop means more slippage and poor efficiency.

[Flying Scotsman]

I would change out your ESC for a high voltage one and run a 580L motor on 6S.

Douggie

[fenalx]

Thanks for your updates.

I measured my currrent prop, and it is 43mm diameter by 51.6mm pitch. I want to give it a try with a smaller prop before getting into the expense of changing motor.

Will stop test should i get a power cut at WOT in order to preserve ESC. Then i would have no option but to get a new motor and motor cooling jacket.

Will keep you posted.

[sailr]

Go down to an octura X440 or Prather 215. You are overpropped for that KV. The higher the KV, the smaller the prop as a rule. 2760KV is more suited for 3S lipo. 4S is a bit over the edge.

[NorthernBoater]

What is the C rating for the batteries. You may also be triggering the low voltage cutoff.

[Flying Scotsman]

The problem is the length of hull with dubious electronics. It will run fine with the expected goals of the manufactuers market. If you want to hop it up...change out all the drivetrain and electronics

Douggie

[fenalx]

Lipo C ratoing is 20C. I switched off low voltage cutoff NorthernBoater becasuse i thought of that. I had tried running on 2S only, but still got same result.

The problem is definately overpropping. Gonna try a prather 215 this weekend, and post results

[ED66677]

Douggie is right!

I would change out your ESC for a high voltage one and run a 580L motor on 6S

that is certainly the safest solution that will give you plenty of power

The problem is the length of hull with dubious electronics

the 200A ESC can do it without problem, I've seen bigger hull than that running fine with it, but a Feigao XL will be on the edge for this big hull
check this thread http://forums.offshoreelectrics.com/...ead.php?t=4159