Akula II Nuclear Engine Room Total Meltdown

[corsaire]

Today happened the unexpected. After about two hours or so of slow, scale running, the speed controller started acting up on me, at first by "losing power", sort of shutting itself down, at first I thought it was the battery but it still had plenty of juice, then after a while the speed controller started going crazy uncontrollable and shut itself down with the boat on the surface in the middle of the pond, had to go for a swim to retrieve it.

Would you consider this a total loss as far motor (Graupner SPEED 7.2V), servos, fail-safe device and pitch controller? Speed controller was the Mtroniks Viper Marine 15. The WTC wall got a blister (pic) due top the heat apparently, but it doesn't leak.
Please, provide your assessments and advice. Thanks.

[southern or]

You have a wiring diagram? I've never had a viper go out on me, but that doesn't mean it couldn't happen. Why are your battery leads going to screws? Whenever I have to have a junction I solder it to reduce a short then coat the crap out of it with electrical tape. Outside of that, it's time to replace it all. Even if the WTC doesn't leak, that doesn't mean it isn't compromised.

[Guest]

You have internal short, probably in the esc, but I would check the motor too. I've seen other mtroniks esc's chenobyl like this, I prefer to use microgyros esc's, as they have better specced components- I still fit fuses though, because no circuit is immune from shorts, especially one which incorporates an h-bridge (https://en.wikipedia.org/wiki/H_bridge).

I'll bet you didn't have a fuse in the main power line. A few pennies worth of fuse would save all this.

I would expect the other components to clean up with a bit of lacquer thinners, perhaps apply some new clear heatshrink to your pitch controller.

The esc is toast, but if you send it back from whence it came, you might get a new one if it isn't too old. Running a separate BEC isn't a bad idea with these ESC's, and make sure you're well over specced on current handling, I would go for a 30 or even 40A mtroniks in that boat.

[southern or]

You have internal short, probably in the esc, but I would check the motor too. I've seen other mtroniks esc's chenobyl like this, I prefer to use microgyros esc's, as they have better specced components- I still fit fuses though, because no circuit is immune from shorts, especially one which incorporates an h-bridge (https://en.wikipedia.org/wiki/H_bridge).

I'll bet you didn't have a fuse in the main power line. A few pennies worth of fuse would save all this.

I would expect the other components to clean up with a bit of lacquer thinners, perhaps apply some new clear heatshrink to your pitch controller.

The esc is toast, but if you send it back from whence it came, you might get a new one if it isn't too old. Running a separate BEC isn't a bad idea with these ESC's, and make sure you're well over specced on current handling, I would go for a 30 or even 40A mtroniks in that boat.

I agree with that. Fuses are amazing things and using a motor and ESC that are rated higher then needed work better then running parts on at near minimum capacity. I learned that (ironically with a micro gyros ESC) after my motors caught fire and the ESC welded the battery connections. Just for fun, is anything rattling around in the motor, and what does the back end of it look like? Also, how'd the battery fair?

[bob the builder]

If you guys recall, there was a thread on sub-driver.com that brought to light a spate of these Viper ESCs erupting like this. It's not a wiring issue. The units were bad in a batch.

[corsaire]

This was definitely as other have attested a case of bad lemon (batch), an issue apparently a bit common in this brand, of course we hope it never happened to us. I took almost everything apart and cleaned it up the best I could. I tested the motor, using a Nicad battery and seems to work just fine, but I won't know for sure if the other electr. devices really work fine until I get a new ESC. The damaged was limited to inside the pressure hull, the ESC got wasted obviously and that blister in the WTC polycarbonate wall.

Can you guys kindly recommend a very good one (small enough to fit in a WTC) other than Mtroniks of course. I've heard of Vantec's ESC (Canadian) which does away with the annoying chirping noise when the throttle is on, of course it'll need to be well speched, high rated for 30 or 40amps as suugested. Motor is a Graupner SPEED 500 7.2V (high rpm) and the battery I currently used is a Lipo Duratrax 11.1V 5000amh. Battery BTW is just fine. Skip Aday used to sell many years ago one that had emphasis on a slow start so that it wouldn't slam the drive train and very silent at that, not sure if it was high rated though. Any input and advice on ESC welcome.
Thank you.