Issues with boat continually cutting out???

[hughb]

Hi guys,

I have an Osprey mono with following specs:

Turnigy 56 series motor (1320kv I think)

Swordfish 240A ESC

Zop Power 6S 4000mah 60C (2 in parallel)

452 prop

I took the boat for its first run the other day, and I keep having an issue with the boat briefly cutting out every second-it sounds as though it's changing gears. Very occasionally it may get on plane and allow full power for approx 4 seconds before cutting out again.

Bringing the boat back in to check temps I recorded the following (all temps in degrees Celsius):

ESC: 75

ESC Capacitors: 105

Motor: 40

If you look at the rooster tail you'll see it constantly cutting out. Toward the end it gets a solid run of about 4 seconds.

What is going on here? I was reading on a similar thread how the LVC kicks in on the Hobbywing 180, could the same thing be happening on my Swordfish 240? Do I need extra capacitors to ensure a constant flow of current to the motor? Would some type of temperature cutout be kicking in, the capacitors @105C seem extremely hot. Is the prop too big, though a large 56 motor surely should be able to handle it.

[photohoward1]

Voltage cuts-off. Try a smaller prop and see if it cuts out. Or program the controller...for lower voltage cut-off.

[Fluid]

If you don’t know the motor Kv it is tough to diagnose the problem if the prop is the issue. The most likely cause is the LVC. What is the setting now? Set the LVC to 3.0-3.2 volts and see if that helps.

Your packs may not be able to supply sufficient voltage under high load, from what I read they don’t have a good rep when used in high load applications. Plus, others report that the rated capacity is way too high, the actual capacity was almost half of the published rating. This would mean that in theory your packs would max out at 280 amps, but if the C rating is also inflated (Zop is known to do this) then the max amp draw for your packs may be well under 200 amps. I don’t know that this is the case with your packs, but it is one possibility. Lowering the LVC value would help with this.


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[hughb]

Thankyou for the responses. I'll try changing the LVC tomorrow. And yes I've heard Zop Power aren't the best of batteries, there's some Revo's i have lying around somewhere i should solder some connections on and give a try as well.

[Peter A]

It could be the esc. I had two SF220 esc's that did similar but not as bad. They would cut out briefly at full throttle. One did about 10 runs and died, the other damaged itself and was unuseable. Hope it's not for you but if so you can send them to heifei for repair, still no guarantees though.

[Old School]

The motor is a Turnigy T20 1280kv for info. The ESC has standard capacitors. Additional capacitors were purchased but not as yet fitted. Initially programmed for a soft start.

Edit: when I looked back over the build log I believe that the ESC is a Hifei Swordfish Pro 200 amp (200 amp continuous/240 amp max for 5 seconds) with remote BEC. I cannot recall if this one made it in the final build or the 240 amp ESC was fitted. The manufacturer spec max amp draw on the T20 when wired for 1280kv is 228 amps. I am wondering if I erred a little with the ESC selection.

[Fluid]

The motor Kv is good for a 6S boat, but 6S isn’t very much for a 42” boat. Most boaters will run either 8S or 10S in a boat that size, running 6S means about 35% to 70% more amp draw for the same performance. But that is a separate issue...

The problem is almost certainly the LVC, setting it lower should help with the cut offs during acceleration. That is not due to the ESC maximum amperage rating, higher rated ESCs would have the same problem as long as the LVC operated properly. Why it is cutting off is likely that the amp draw is too much for the packs to supply enough voltage under load. Better batteries would solve that problem. A smaller prop coukd help, but reduced thrust means even lower performance.

I am only indirectly familiar with those ESCs as I have watched numerous fellow club members use them. If they have good over-amp protection, then the cutting out could be that protective circuit. But I have seen too many Swordfish burn up (nearly a dozen) to have much faith in their amp protection.


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[Old School]

Fluid,
many thanks. 8s would give around 35,000 rpm which may be a little high but still reasonable. My son has a fair collection of batteries so all it would need is reprogramming the ESC (Swordfish pro 200 is good for up to 8s I believe) and suitable batteries. If a 240 amp model then I believe good for up to 12s. The motor is dual rateable so could be rewired for 730kv. Thus if setting the LVC is not a fix then he has a couple of alternative fixes, although continuing on with 6s is obviously going to mean higher amps and temperatures. I believe that the boat has potential so worth further investigating.

[Fluid]

Yep, 8S with that wind is too much. Those who run 8S and 10S use lower Kvs, often around 800-900. The 730 Kv wind would work too, just needs a slightly bigger prop. Most certainly continue with the boat and keep us posted.


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[Old School]

Fluid,
many thanks. From memory I had intended for the boat to run 730kv on 10s, however as two other project needed 6s batteries for a 6s and a 12s setup, I decided to save purchasing additional batteries and just go with 6s on this build.

[hughb]

Yes Old School was correct, it is a Swordfish 200A Pro ESC.

[hughb]

So I changed the LVC down to 3V and soldered a Hifei cap bank onto the ESC. The problems seem to have virtually gone, maybe still some very occasional cutouts.

I did 2 runs, first with Revo packs, second with Zops, couldn't notice any discernable difference between them. A funny thing happened, on both runs the boat got slightly airborne then plunged into the water, fully submerged for several seconds before bobbing back up to the surface. By the third run i think some water got into the reciever and killed it, I've replaced it this afternoon and the boat is working again. Thanks for your help guys.

[mmars89]

Hello FE friends,

Going to see if I can revive this thread. I am having the same issue with my twin cat running 240 Swordfish ESC's.

Set up:
Delta force explorer, carbon inlay
Swordfish Pro plus 240 HV ESC's
1000kv 4082 Leopard Motors
Fly Sky GR3E receiver and GT3B Trans
Tenergy 6v 2000mAh NiMH receiver battery
Power HD D-15HV servo
Running 12s with 2x 6s Zeee 6000 mAh packs in series, common to both ESC's

https://www.youtube.com/watch?v=dRgmXNl4rtw

According to the data logs I'm only pulling a maximum of 156A with the voltage dipping to 42.5v at the lowest point, this got me to 100mph. Trends show throttle signal is coming through, leading me to believe it's not a receiver problem but an ESC problem.


What I have tried;
LVC is set to lowest possible setting, 4s 2.5v. Did not solve problem
Separate power sources, 6s per ESC, on their own battery. Did not solve the problem
Props from 442's to 50mm plus, 2 and 3 blade. All the same results
Made wooden block to get receiver away from carbon. Did not solve the problem
Switched receivers (in kind). No change
Changed Y cable, no change
Pulled positive wire in Y cable, no change

IMG_9822.jpg

Any help would be appreciated.

Thanks

[Peter A]

Your weak link here are the swordfish esc's. I have in recent months seen several develop issues on 10s in 1/8 scales with fairly low amp draw, including cutting out and stopping working, then later working ok on the bench, or even blowing the + lead off! I had a SF 300 that went well with a Castle 2028 though. The 240 doesn't like water either.
The only other problem might be your radio, they can do funny things at times, cutting out at particular spots on the water.

[mmars89]

Your weak link here are the swordfish esc's. I have in recent months seen several develop issues on 10s in 1/8 scales with fairly low amp draw, including cutting out and stopping working, then later working ok on the bench, or even blowing the + lead off! I had a SF 300 that went well with a Castle 2028 though. The 240 doesn't like water either.
The only other problem might be your radio, they can do funny things at times, cutting out at particular spots on the water.

It's definitely looking like it's the ESC's. I don't think it's the radio, it works flawless in multiple other boats, one being full carbon. Swapped receivers around and the problem stays with the ESC's. Also, the throttle signal shows no signs of dropping out on the data logs.

When they decide to go, they go. Either one cuts out until I let off the throttle. Seems to be most prominent during acceleration. They will go then cut, repeatedly, getting a little higher RPM each step until they eventually decide to go wide open. Takes me half the lake to get them to go sometimes, but when they do light up, they do not drop out again. It's strange.