My Impulse 31 misfortune

[de-pro]

So I have done a few mild mods since I got the boat. The most latest was installing a UL-1 motor and a very impressive cooling jacket I got from OSE.
Then I decided to to go with a hotter prop for this boat. After reading several threads and based on the availability, I ended up purchasing the sharpened and balanced X447 prop.
I installed the prop knowing I have to monitor the temps at the first few runs to make sure everything is ok. I started out with my older flightmax 5000 30C batteries I had kicking around. First off this prop made the boat go like a bat out of hell after a couple of minutes of run time I brought the boat in and checked for temps. ESC and motor were both around 100 degrees so was the battery. So that built some confidence in me and I changed the batteries to Gens Ace 5000 40C. Well I think that did the job, after running around a minute, the boat stopped. So we brought it in and immediately smelt the bad news
The ESC was done. The wires for the motor and the negative wire to the battery were just completely unsoldered from the board and sticking out of the ESC. Also burnt smell all over the boat and marks on the rear of the boat where ESC sat.
I guess I misjudged the fact the higher C rated battery can produce more current for the load on the motor. So much that ESC could no longer handle it. Thanks for a few tips on this forum, I cleaned up the Hull (although the sting is hard to get rid of) checked out the hull once clean and saw no visible damage. Please have a peak at the attached photo and tell me if it looks ok.
Also as a side note, I bought the upgraded trim tabs for the boat but I am having a hard time figuring out how to adjust it due to the design of the rear of the boat. Any advice on how I can work around it? I was thinking of making a small hole on the trim tab and turning the screw upside down. However I dont know what kind of effect the hole will have on the boat handling.
Thanks for reading and any advice you can provide.

[Racer944]

You have the right idea for the trim tabs... Darin Jordan showed this mod in his thread, and I did the same to mine... Here is a pic of my install.

Eric

P.S. Sorry to hear about the ESC...

Impulse 31 repaired trim tab screw and Speedmaster tabs 2.jpg

[Darin Jordan]

An X447 is a LOT of prop for a UL1 motor... especially on a Mono...

[martin]

You probably done the damage with that size prop rather than battery c rating.

[Fluid]

after a couple of minutes of run time I brought the boat in and checked for temps. ESC and motor were both around 100 degrees so was the battery....

This is hard to believe based on my experience with UL-1 motors in several hulls - none monos. What does "around 100" mean? Did you use a temp gun?

Most of us running that motor in P-Limited Hydros see higher temps with an x445 running two minutes in the summer, how it could be lower in a mono with more prop is surprising unless your Canadian water is ice cold. Did you let the motor and ESC cool down between runs? Like the others I believe the packs weren't the problem, the prop was just too big. Why you didn't see the problem coming after checking is surprising - sorry for the burndown.


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[de-pro]

Thanks for clarifying about the trim tab. Is there a hole made on the tab for the driver or just using a needle nose to turn the screw.
Darin, I am pretty new at this so I went for what was available at the time. I wanted it sharpened and balanced and its very hard to find those here. The UL-1 motor will be replaced by a Leopard 4074 2200Kv. I have lots of 2 cells and didnt want to get into lower kv higher voltage path. I also ordered the seaking 180 ESC. I hope this setup will be fine. I really loved that prop.
Martin, I know the the prop was behind all this but no damage was done when running the lower C rated battery. The reason the ESC died was because more current was fed to the motor through it by higher C rated battery. I gotta use the 70% load rule when pairing motors to ESC.

[de-pro]

100 degrees farenheit. I use a temp gun from my offroad vehicles. 1300 mah was taken from the flight max with no damage to ESC. Cooled down the escs and motor by injecting fresh supply of water and ran again. 600 mah into the new packs and she cooked.
I am actually not claiming any fault from the battery. Its fault was producing lots of juice to the motor as demanded by the bigger prop.
It has been cooler in here recently and the water temp should be in 70's where I go.

This is hard to believe based on my experience with UL-1 motors in several hulls - none monos. What does "around 100" mean? Did you use a temp gun?

Most of us running that motor in P-Limited Hydros see higher temps with an x445 running two minutes in the summer, how it could be lower in a mono with more prop is surprising unless your Canadian water is ice cold. Did you let the motor and ESC cool down between runs? Like the others I believe the packs weren't the problem, the prop was just too big. Why you didn't see the problem coming after checking is surprising - sorry for the burndown.


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[martin]

The point i was making was if you used the correct size prop then the higher c rating wouldnt blow the esc.

[de-pro]

No doubt. need for speed got the best of me and after seeing what that prop can do, then there is no going back to a mild setup :)
This is a great boat and has lots of potential. Like any RTR, the electronics are not meant for anything extreme.

The point i was making was if you used the correct size prop then the higher c rating wouldnt blow the esc.

[Racer944]

de-pro;

I drilled the hole in the tabs just large enough to get my allen driver through to turn the screw. I guess if you wanted to use needlenose pliars to turn the screw head, you could probably do so without drilling the hole... just flip the bolt over to make it easier to reach.

Eric

[de-pro]

Thanks Eric. Its appreciated

[Diesel6401]

The higher C rating did not cause the esc to fry, the size prop you used did. The higher the C rating the better when it comes to boating. The batteries only supply the amount of amps that the motor demands. Just because your batteries can put of more amps doesn't actually mean the extra amps are being used. The motor pulls the amps the esc recognizes the amp load and request that amount of amps from the batteries. Higher c rating didn't have anything to do with that. A x447 if a very LARGE prop especially on ul1 motor.

[de-pro]

Thank you. Is there a specific prop upgrade that is safer than x447? This motor and the replacement esc I got is going into a supervee.

[Diesel6401]

Thank you. Is there a specific prop upgrade that is safer than x447? This motor and the replacement esc I got is going into a supervee.

That motor is a very good choice for a SV27. I ran that ul1 motor in my sv with a grim 42x55 with great results..

[de-pro]

Thanks I will get one 42x55 on order. Please keep in mind I will still be using the stock 60amp esc