Esc Smoked for Unknown Reason. ideas?

[sanyijr]

Specs are as follows:

New 14L (1755 RMP/V) Feigao motor 3.5 mm connectors
Used 100A ESC
new Speedmaster stinger 0.130
new well S&B X637 prop and bullet nut
2-2 cell 4000mah batts in series (14.4V total)
hull is a DF26 with cg about 9 inches from back.

Except for the final result, this setup was incredible. I only have the Fast Tech to compare, but still, super smooth, and fast and extremely stable. After 3 runs and testing temps, I got a visit from Smokey the Bear. Not sure why. I did three short test runs before, increasing the times and speeds of each. Till on the last run, Smokey dropped by.

Batteries were not very warm, motor was pretty warm but not sizzling. ESC fried along with reciever that was near by. Any thoughts on why or what to check to verify things here?

Stinger drive is pretty smooth, rotates pretty freely. It did seem slighlty stiff right after, but I wasn't paying that much attention to that specifically. But now it is smooth.

The only other thing that I noticed that may have been off is the water outlet. The amount of water coming out was less than my Fast tech. But when I blow throught both boat's pickup hoses, the Fast tech's cooling system is actually more restrictive. The pickup on my DF26 is over 1 inch below the boat bottom.

If it's long winded...I figure more is better (unless we are talking about smoke :doh:)

I just don't see where I skrewed the pooch on this one?....

[Diesel6401]

Specs are as follows:

New 14L (1755 RMP/V) Feigao motor 3.5 mm connectors
Used 100A ESC
new Speedmaster stinger 0.130
new well S&B X637 prop and bullet nut
2-2 cell 4000mah batts in series (14.4V total)
hull is a DF26 with cg about 9 inches from back.

Except for the final result, this setup was incredible. I only have the Fast Tech to compare, but still, super smooth, and fast and extremely stable. After 3 runs and testing temps, I got a visit from Smokey the Bear. Not sure why. I did three short test runs before, increasing the times and speeds of each. Till on the last run, Smokey dropped by.

Batteries were not very warm, motor was pretty warm but not sizzling. ESC fried along with reciever that was near by. Any thoughts on why or what to check to verify things here?

Stinger drive is pretty smooth, rotates pretty freely. It did seem slighlty stiff right after, but I wasn't paying that much attention to that specifically. But now it is smooth.

The only other thing that I noticed that may have been off is the water outlet. The amount of water coming out was less than my Fast tech. But when I blow throught both boat's pickup hoses, the Fast tech's cooling system is actually more restrictive. The pickup on my DF26 is over 1 inch below the boat bottom.

If it's long winded...I figure more is better (unless we are talking about smoke :doh:)

I just don't see where I skrewed the pooch on this one?....

increasing speeds? does that mean you where running less then half throttle for a extended period of time? Link to the esc you had?

[sanyijr]

increasing speeds? does that mean you where running less then half throttle for a extended period of time? Link to the esc you had?

Correct. First run was little over 1 minute and ran up to 1/2 throttle.

Second was 2 minutes +/- and upt to 3/4 throttle on a few short straights.

Thrid/Last 2.5 minutes and went pretty steady 50-70% throttle with 3-4 straights at WOT.

Each run was with fresh charge and at least 1 hour between runs. (so cold to start)

ESC was a Xpower 100 A continuous, 120 A max.... (that is all I have) There was no stock thermal wrapping on it with labels.....

[Diesel6401]

Correct. First run was little over 1 minute and ran up to 1/2 throttle.

Second was 2 minutes +/- and upt to 3/4 throttle on a few short straights.

Thrid/Last 2.5 minutes and went pretty steady 50-70% throttle with 3-4 straights at WOT.

Each run was with fresh charge and at least 1 hour between runs. (so cold to start)

ESC was a Xpower 100 A continuous, 120 A max.... (that is all I have) There was no stock thermal wrapping on it with labels.....

The running at less then full throttle for extended period of time prob resulted in your esc failure. Believe it or not running less then full throttle creates more "work" for the esc which results in heat. Esc is switch either its on or off. When you run less then full throttle the esc has to cycle on/off rapidly to meet your throttle demands. In land and air rc models it's not that big of deal (less friction and amp draw) and car escs typically have oversized external caps soldered on the esc to help with the on/off throttle management that is really heavy in cars, boating however is a whole different animal and im pretty sure that the style of driving you described lead to your failure (add the fact a lot of cheaper escs amp rating is overrated) and you have the failure you described.

[sanyijr]

Diesel,

I have heard that before about overworking an esc at low speeds as you say. But then if you buy a 120 amp rated esc and run at full throttle but only draw 60 A. Is that different?

The esc is cycling at 100% but just not at that amp draw?

What would you recommend then as an esc?

[Diesel6401]

Diesel,

I have heard that before about overworking an esc at low speeds as you say. But then if you buy a 120 amp rated esc and run at full throttle but only draw 60 A. Is that different?

The esc is cycling at 100% but just not at that amp draw?

What would you recommend then as an esc?

You have the extra cap room (amps), but your still causing the esc to rapidly switch on/off which still creates excess heat, also amp spikes are more frequent at half throttle running as the boat as a tendency to be on/off plane.

Swordfish 120 from here at OSE. Get the usb programmer with it. Make sure you waterproof the esc though. Click my youtube link for a video on how to waterproof.
http://www.offshoreelectrics.com/proddetail.php?prod=hef-sword-120

[sanyijr]

Thanks D....

One followup on the amp spike, etc. On my fastech, I can run that pumpuing the throttle through all 5,000 mah and not have any heat. The motor is cool as the water and the esc is not even warm to the touch. I did not think my setup was that much different? Obviously it is. But why?

[Diesel6401]

Thanks D....

One followup on the amp spike, etc. On my fastech, I can run that pumpuing the throttle through all 5,000 mah and not have any heat. The motor is cool as the water and the esc is not even warm to the touch. I did not think my setup was that much different? Obviously it is. But why?

you would be amazed how fast temps drop, using a eagle tree data logger tells the true story on how hard your electronics are getting worked. motor quality and efficiency always plays a part, your fastech motor is 6pole 1500kv on 4s the rpms are a lot lower then you feiago motor so amp spikes are lower and also the pb motor is better quality.. could be a number of different reasons.



at the end of the day work on staying full throttle for almost the entire run, that will save you in the future.

[sanyijr]

Thanks again Diesel,

Makes sense. I guess I need to either drop a cell or get a lower KV motor.... The thing is pushing mid to high 40s on that setup and my water is not flat enough for continuous wot..... But great points. Thank you!

Might just get another Fastech motor and maybe a good esc and call it good.

I thought i would love pushing the speeds in to the 40's. But I do not have the space or water conditions for this.

[Diesel6401]

Thanks again Diesel,

Makes sense. I guess I need to either drop a cell or get a lower KV motor.... The thing is pushing mid to high 40s on that setup and my water is not flat enough for continuous wot..... But great points. Thank you!

Might just get another Fastech motor and maybe a good esc and call it good.

I thought i would love pushing the speeds in to the 40's. But I do not have the space or water conditions for this.

swap motors. drop the feigao in the fastech and put that motor in the df26. you still can use the x637 on th df26 and the lower kv will drop the speeds down on the df26 and the fastech can handle rough water very well .might be worth a try before dropping $$$ on a new motor. just a thought. or try running the trim tabs negative on the df26 and that should have it running a little more wet.