Trolling motor?

[greenkarson]

What do you guys think of these? http://cgi.ebay.com/ebaymotors/Trolling ... iesQ5fGear

they are a perfect size and thrust for my situation. But just wondering are they brushless motor that can work submerged in water or are they just a sealed motor that won't be able to handle the pressure at the depths i want to go? 500' to 600'

[manhattan]

Doubt that it’s a brushless setup and I would be surprised if they handle 100 feet multiple dives. Think we are looking for similar thruster requirements and after a lot of research I am going to test dive brushless as deep as possible un-sealed and if that doesn’t work out I am going the “magnetic coupler” way (which I am trying to avoid)

Joe

p.s. tested the motors on 8 meters depth without issues

[thegadgetguy]

Yes, I would have to agree that I don't think they would do 500-600'. I think people normally use them because they have way more thrust. They may be able to go sligtly deeper than a bilge pump, because of the large components, but if you are aiming for 500', you are definitly going to have to go the brushless motor or magnetic coupling route.
Welcome to the forum and good luck!

[greenkarson]

Was just reading online that a brushed motor will run fine underwater as well. Of course with some lost power do to water resistance. With lots of tlc on the motors when removed from the water maybe a little oil to prevent any rusting. That being said why could'nt i drill a couple of holes in these trolling motor casing to let them fill with water to eliminate the outside pressure?
I know this may not be ideal but in theory should'nt it work?

[greenkarson]

how about just adding some sort of port to the casing and adding a light oil?

[thegadgetguy]

Drilling holes in the casing to allow the water in would most likely not work, since these motors are not designed to get wet, hence the waterproofing. It might work if they are brushless motors, but I don't think that they are.

The oil idea is defenitly a posibility, the only problem being that it can be hard to get the oil to stay inside the housing; the housings are designed to keep water out, not oil in.

[soulreaper]

Hi everyone. PLEASE READ ALL OF THIS BEFORE YOU CLICK ON THE LINKS I HAVE INCLUDED. I know I'm still new at Underwater Rovs but I have been into radio controlled airplanes, cars, trucks, boat, dirt bikes, if it has to do with R/C I have done it most of my life. Listen, DC motors whether brushed or brushless, do not care if they are wet or dry they will run the same wet or dry. As a matter of fact if you go on Youtube and type in brushed motor break in you will see people breaking in brushed motors in water. If you continue to look you will also see people running brushless motors in water also. Most of my rc vehicles are brushless or brushed and I have submerged my E-maxx in rivers and it still runs fine. Youtube E-maxx underwater. Search waterproofing brushless esc and you will see a popular guy run a brushless motor underwater. If your still not convinced I will do a demo myself of brushed and brushless motors underwater. Here are a few links of other people http://www.youtube.com/watch?v=VBqMCqeS9LA Even in the first video this guy is new to this concept and states that you cant do this to brushless motors, He was wrong as I prove this in the next video http://www.youtube.com/watch?v=aoCnXOAI ... re=related These are just two of many videos, check for yourselft. In the second video I posted this guy who has done a lot for this sport (underwater rov) made so mistakes in his first video. He did not know how an esc worked when voltage was low. He finally figured it out and made this final video. People think water is an excellent conductor of electricity.. THEY ARE WRONG!!! water is a piss poor conductor. Here is an experiment you can do at home if you don't believe me. Take a glass of water. Take your multimeter and set it to OHMS and do a continuity test. Stick both probes into the water about an inch apart and keep moving them closer and closer together until you get CON. How close do you think they will have to be? You will be surprised.. I have watched people talk about this concept for a while and I have kept my mouth shut because I did not want to start a debate about this but I had to step up to the plate. I have tried to be a good forum member so please dont think I'm trying to start some thing. Again if you want me to do demos of anything I have wrote in this post just let me know and I will find the time and make some videos for you to see. Trust me I'm only trying to help.

[thegadgetguy]

Do you have any experience using brushed or brushless motors in salt water? I know water doesn't conduct electricity, but if it has an ionic compound disolved in it, then it will. Is the water still not conducvtive enough to cause a short circuit?

[soulreaper]

That is an excellent question. You have me there. I have never submerged any of my R/C's in salt water so I can not answer that question. My experience has been with Fresh water only. Maybe someone else could answer that one.

[greenkarson]

salt water won't be a problem for me. freshwater only. but i think i will still fill the casing with a light oil.