running motors underwater

[Grant Tokumi]

Anybody ever tried to submerge their motor and/or battery underwater while operating? I thought something like that would short out, but now I'm not so sure.

I saw an episode of the TV show Junkyard Wars and in that show they were given a task to make an underwater propulsion system. One team used a 12 volt motor (starter motor?) hooked up to a car battery. The part that confused me was the system was NOT enclosed in an airtight container. The motor and battery, not to mention the team members hanging off the back of the unit were all exposed to the water. And if I remember correctly, the show explained that the team members were safe from shock because of the low voltage. ??? A 110 volt (like house outlet) would kill, but not low 12 volt. I didn't believe it until I saw it. But why didn't the battery short out? Am I missing something here? Internal resistance in the battery? And if they could do that, I wonder if we really CAN run our stuff through raging flood waters (scale flood of course http://www.rccaraction.com/ubb/smile.gif ) without worry of shorting out our batteries. Waterproofing the ESC, receiver, and servo I think is still a must, but who knows, maybe submerging those is ok too. I've never tested it. Any insights?

[TCorzett]

The volts aren't what kill - it's the amps. But then again if you can move a sub there's enough amps to do some damage. I love JunkYard Wars (especially the tractor pull one). Well I've never submerged a car, but I have run one through a puddle. NOT A GOOD THING. You get some nice pretty blue sparks, but it is not good for the car. When I hit the puddle the freshly built RC10 buggy (this was about 10 years ago...) took off down the street winding up in a pile of wet leaves. The car worked after (still use the electronics today) but wasn't good at the time. I'm not a genus when it comes to electronics, but water doesn't mix. I'd love to hear other people's comments/experiences with water...

[Ranchdreson]

well they did wrap the motor with duct tape. I like the old junkyard wars with the other guy host.

[rc10gt_bb]

I didn't like all the english acents on the old one. Did you see the one on the dragsters. They looked cool and the hit 80MPH! One ran on a moto engine and was small and lightweight and the other one ran on a v8 and was large and heavy. The race was realy close.

[LosiMan3456]

Is Junk Yard Wars on regular T.V. If so what channel and what time? I have heard about it and it sounds awesome. I also like wathcing Battle Bots. any body else watch it?

[GTman]

you can run that stuff underwater but don't expect it to be good for the batteries and motor.

[broken_parts]

i watch battle bots all the time.

[J mAn]

yah i watch that show, i figured alot of people on here would like it. I didn't see the epasode with the motor but i think it would short out. Was the motor itself above water?

[J mAn]

it's on tlc on wendesdays from 9:00 to 11:00. It's on regular tv.

[rc10gt_bb]

I did not get it until my cable company got TLC a while back. But I do have cable if thats what you mean.

[SRBaja]

Take your motor out of your car and stick it in a can of water it will run just fine through your radio control system. You can break in brushes that way

[DaBrew]

A guy at Hobbytown USA in Vegas told me how to break in rc motors underwater. I broke in my Trinity SPEED GEM, 11 turn, modified, that way. Here's what he told me: 1. Install capacitors and wires. 2. submerge motor completely in glass of water. 3. Hold battery and motor leads together for aprox. 30 secs. or untill water turns grey[dirty]. 4. Repeat using clean water untill you hear RPMs increase, and hold. It took 4 times for my motor and it RIPS! I have an Associated: RC10-B3. It really screams!

[Grant Tokumi]

I was unaware of breaking in motor brushes underwater that way. Sounds like a great idea, I will try it.

It sounds like the motor is safe to submerge without affecting the battery or other electronics. It still baffles me though. Why doesn't the water short out the battery? I would think dipping the motor into the water is the same as dipping the battery connector into the water. So I'm wondering exactly what happens if you put a battery pack in water? I guessing it won't short out now. It didn't short out the battery on Junkyard Wars. But will it start discharging in any way? I always assumed water to be as good a conductor as a piece of wire. Maybe it isn't.

Still confused.
Grant

[SRBaja]

Ask you science teacher to explain it

[SirSpeedy]

This will really get you.

Water does not conduct electricity........ what do you think of that?........

This is NOT the kind of testing we want anyone performing. Please.......

[This message has been edited by SteveP (edited 01-11-2001).]

[Grant Tokumi]

Wow, thats a new one to me. You're saying water (tap water) does not conduct electricity. I guess I must have been absent during that lab. http://www.rccaraction.com/ubb/smile.gif Thats an interesting lab scenario though. I'm curious what happens if you just cut both wires from the lamp, plug in the cord and dip both those loose wire ends into the water. If water didn't conduct electricity, then that would be safe too right? Instinct tells me thats a VERY bad thing to do. But that lab experiment scenario SirSpeedy describes tells me otherwise.

There must be something missing here. No discredit to SirSpeedy, http://www.rccaraction.com/ubb/smile.gif I think it is one of those great "eye opener" experiments. Makes you think. However, if water was a 100% insulator (didn't conduct electricity at all), then we we wouldn't be protecting our electronics from it. Any physics or science teachers/professors out there? Whats the missing element here.

I'm pursuing this matter to better understand exactly what parts of our electronics need to be completely protected. I thought motor was in that catergory, but from the previous posts, it seems like motor can actually be submerged unprotected with no damage. What about battery, receiver, servos (non-waterproof servos)?

To protect or not to protect.
Grant

[J mAn]

I'm still trying to understand this.

One day during a race it started raining, about 30 seconds later when it realy started raining hard anadthey just called the race off my motor started smoking and the car stped running. Was this because of the rain or something else?

Will water short out electonics only if all 4 or more wires are contacted at once?

Can someone plese explain a litle bit further?? I'm sure alot of people would like to know.

[SirSpeedy]

Did you guys do the experiment?

The starter motor on you full scale car get wet often, and they are far from sealed.

As for the electronics issue, I would assume that as long as it was clean water, it would not hurt them as well. I have seen people run them on the beach, and run into the surf and ruin radio equipment. But then again, a conductor(salt) was present.

I have done the water break-in many times. It will not harm the motor.

[Grant Tokumi]

I have not done the experiment. Did you do this in a school lab? Was it a battery lamp or one you plug into the wall? I'm assuming you've done this in school for a science experiment, and if this is so, then I have no doubt that you are correct in that the lamp will not work with one wire cut and dipped into water like you describe. It puzzles me, but I take your word. Plus, I kind of don't want to sacrafice a lamp and/or trip my home breakers to find out. Someone told me one time that you can poke 2 metal wires, one into each end of a hotdog, and put the other ends of the wires into an electrical outlet. This is supposed to cook the hotdog. I believe him, but still wouldn't want to try it. The question still remains though, "why does your experiment act how it does?" When you talk about adding the salt and then it works, that puzzles me too as to why. At first I thought that the impurties in the water is what conducts the electricity through the water, and distilled water or absolutely clean water would not conduct electricity. But I thought about the other posts where they break in the motor in water. The dirty water should fry the motor once it gets too dirty. But I'm suspecting that water sure gets dirty when breaking in motors. Junkyard Wars used their system underwater in a swimming pool (which usually is filled with chlorine). And JmAn suspects that the rain (relatively clean) fried his stuff. I've also experienced smoking batteries when running one time on the wet grass. I blamed water, and it was clean water. So I'm speculating it can't be just "impurities". The experiment uses salt. Is it that ONLY salt water conducts electricity and all other water is an insulator? It seem that clean water can fry stuff too.

That electricity is weird stuff.

[SubaruTiburon]

Well..it goes a little something like this. h2o is water..of course...almost everyone knows that, its also a non-electrolyte. It doesn't conduct electricity normally. What SirSpeedy said is totally correct. We even did this in Chemistry. If you even want to consult my teacher, be more than welcome to mharold@epix.net is his email. He'd be almost glad to help you out. ANYWAYS..wa wa itself dont conduct the lectric.

Ditto

[This message has been edited by SteveP (edited 01-11-2001).]

[yankees2000]

im relatively new to rc...This is what i got so far on breaking in a motor...Put the capacitors on (i dont have to cuz my p2k has them already)hook up electrics (connect the radio???), submerge...nd then im lost. How much of a batt do i use?

[rvrrun]

Someone told me one time that you can poke 2 metal wires, one into each end of a hotdog, and put the other ends of the wires into an electrical outlet. This is supposed to cook the hotdog.

Yep, that one works. Had to do it as an experiment in college. Tasty experiment.

This one is pretty interesting. I've always lived by the rule that H2O and electricity dont like each other, but the argument about pure water being an insulator makes sense.

Time to go brush up on the chemistry and physics.

[SirSpeedy]

Yankee-

Your P2K has serrated brushes. They will break-in the the first couple of times you run the car.

If you are new to RC, just charge up some batteries, grap your stuff, and find an empty parking lot and HAVE FUN!!!

I loved the days when I was not worried about all the crap that I have to be concerned with now that I race competitively.

One day, if you choose to, you will spend hours making sure you motor are properly broken in. Trust me, don't worry about that now

See ya....

[2fast4u]

you can run your motor in normal water with low volages and it should be safe but if there is salt in the water it will short ciruit, the reason you can't use high voltage appliances in water is because there is no such thing as perfectly clean water so the voltage will "jump" farther and short circuit. Its just like resistance beetween two different materials like copper and tungsten(lightbulb filament)

[RCJunkie]

Pure water will not conduct elecricity because of the way the water molecule bonds. The conductors in tap water are the electrolites (salts-calcium, sodium etc.) With the batteries in the water some voltage is carried into the water but the water is not a good enough conducter to carry enough amperage to do damage. Also with the sub example you must take into account the body of water and the fact that the swimmers weren't grounded. A large body of water will dissapate the current in the the water quickly. If you put a twelve volt battery in a sink with a motor and touched the water while you were standing on the ground it would be a different story.
Electricity follows the path of least resistance and as long as there is a good path of conductive metal to follow, that is where the current will be.

[Grant Tokumi]

Ok, things are slowly starting to make sense now. From what I gathered so far:

1- Only "Pure" H2O is an insulator and will not short out equipment no matter what.

2- 99.9% of the water that we are exposed to have a significant amount of impurities to make water somewhat of a conductor and WILL short out equipment in certain situations.

(From this point on, the word "water" will refer to tap water or water with impurities)

3- One factor that determine whether the water will short out equipment is the power of the power source. 2fast4u mentions a larger power source (like house outlet) can jump farther in water and will short out easier than a small power source such as a AA battery. I guess car battery and RC battery falls somewhere in between.

4- RCJunkie adds that a large body of water will dissapate current (amps)and prevent damage to the humans (or equipment). The humans and machine wasn't grounded, so the path of least resistance was the motor.

More to come, my munch hour is over http://www.rccaraction.com/ubb/smile.gif
Grant

[t3 kid]

ok,First off,water is not a pure conductor like gold is.however,unless it is totally pure,totally,it will still conduct a little.Electricity always wants to take the path of least resistance.that's why when lightning strikes it may hit a tree instead of hitting the ground right next to it.A tree conducts more than air.

In the case of putting a motor in water,the electricity will take the path of least resistance:the brushes,the comm and the windings.not the water.

hope this helps,later

[JP]

It works, I would know considering all 5 zillion of my non broken in/rebuilt motors were broke-in by running under water. I currently have about 5 of my RC motors broken in underwater. Who cares about this science mumbo jumbo, I mean, who REALLY paid attention in school, especially that stupid science class where the teacher wouldnt let you BURN stuff? Who likes/liked school?

no one (cept girls)

So why talk about this electricity current voltage resistance crap? Just try it! take a cup; pour sink water in it; break in your motor with it.

And I also dont reccommend usuing a battery if you DO have access to a power supply, batteries cant be adjusted with voltage, because you dont want to break in your motor too fast or too slow.

Lighter fluid is ALSO a good breakin fluid, in fact, it works better! Yes im crazy, yes im a pyro (Pyro4life). But lighter fluid WONT ignite with a motor in it. You say "but the comm sparks! If you submerge it in lighter fluid, it will blow up!"

Truth is a flame or spark WONT occur in a liquid. No kind of fire or spark caused by or ignited/fueled by electricity or ANYTHING will burn under water unless it has air.

Lighter fluid is the same thing, as long as you dont have the motor running when you put it in OR when take it out, it wont ignite. If it IS running while you submerge it, it will blow up because there is a point where it has 3 ingrediants of fire. 1: fuel (lighter fluid) 2: heat (spark) 3: air (before/after you put it in lighter fluid). I dont really recommend you try this, you can ignite it, so use water. I just know this from slot cars. And yes, I HAVE tried this, and it works. But im not responsible for anything that happens to you, anyone, or anything. My disclaimer p

[This message has been edited by JP (edited 01-27-2001).]

[Grant Tokumi]

From previous post:
--------BEGIN-----
<grant tokumi>
3- One factor that determine whether the water will short out equipment is the power of the power source. 2fast4u mentions a larger power source (like house outlet) can jump farther in water and will short out easier than a small power source such as a AA battery.
--------END--------

It seems to me that in this hobby, we stress protecting the receiver, servos and ESC from damage, I guess because of the intricate circuits? I never heard anyone say put your battery in plastic bags. But this seems to go against the argument above that "larger power sources can jump farther" because I would think (here I go thinking again) the current going through the receiver and ESC circuits are small currents, so even if the circuits are submerged, the power should not be able to jump to parts of the internal circuits where it shouldn't go (and shorting out the equipment). So do we REALLY need to protect the receiver and ESC from water?

From previous post:
-----BEGIN-----
<grant tokumi>
4- RCJunkie adds that a large body of water will dissipate current (amps)and prevent damage to the humans (or equipment). The humans and machine wasn't grounded, so the path of least resistance was the motor.

<RC Junkie>
If you put a twelve volt battery in a sink with a motor and touched the water while you were standing on the ground it would be a different story.
-----END-------

Does this imply that if a small drop of water were to go between a + and - contact, it will short out the system, but if those same + and - contacts were totally submerged in water, then it will be fine? If that is so, it would explain why some motors fry when running in rain or wet grass (drop of water here and there) while we can submerge the same motor in water for break in with no damage.

From previous post:
------BEGIN-----
<JP>
Who cares about this science mumbo jumbo,....
------END------

I guess I agree with JP. I apologize because I feel most responsible for making this topic too much unnecessary "scientific mumbo jumbo" http://www.rccaraction.com/ubb/smile.gif.

So here's what I'm trying to get out of this post. If anyone can say EXACTLY what components of our electronics (motor, battery, receiver, ESC, servo, wire connectors?) have to be completely protected from water with proper scientific explanation as to why, I think that would cover the intent of this topic. Then we can go and bash through those 6-inch deep mud bogs in confidence.

Grant

[speedemon]

I had my whole motor in water and it sat there for like five seconds it was a p2k.
And it wouldn't work i let it sit in the sun but it still wouldn't work i took it apart and used sand paper and scrubbed of the rust and my motor ran but when i would stop it wouldn't go again i would half to give it a push.

[OB4_DRIVER]

Water and Electronics = Bad Idea

While it may not be a problem breaking in your motor in a glass of water I don't think I would ever do it. Not for the sake of the electronics (lets face it motor are relatively simple http://www.rccaraction.com/ubb/smile.gif ), but for the sake of the motor itself. can you be sure that once you break in the motor then disassemble it then clean it that you can get all the water out? how about from the bearings? they have labrynth seals that aren't waterproof. My point is you may break in the motor well but you may end up shortening its life by not getting it completely dry. corrosion is a bad thing.
With the speed control and receiver the answer is obvious, keep them dry. the speed control handles just as much current as the motor and it is seldom maintained/cleaned. If you look at your motor the electricity must span relatively large spans of water to find a conducting path. In your speed control things are different. Due to the demand for smaller and lighter speed controls I think every speed control today is built using surface mount technology. this is great for size as some of these components are pathetically small but this also means the gaps between the traces on the boards are also smaller as are the traces themselves. If you submerge the speed control and water gets inside (not many waterproof controls out there) it will not only short across the traces it will destroy the traces themselves. Water across a trace will conduct electricity. It may not be much current at first in the case of pure water but after a short time resistance will go down and current will go up. This water while it is conducting will be acting like a battery ,the traces will be the anode and cathode with the water being the electrolyte. A battery is nothing more than corrosion in a container. period. Material (ions) flows from the cathode to the anode this results in the destruction of the cathode. Think Anodization (coloring of Aluminium parts, same principal).
Salt/impure water is even worse because it already has a bunch of ions in it to speed the process. Stay far away from salt water! (at least with your RC car http://www.rccaraction.com/ubb/smile.gif )
The people in the TV show wern't killed because the motor was the path of least resistance, second to that would be the water between the battery's terminals and then third the positive terminal to the bottom of the pond. The people were not in danger because they did not represent any path of lower resistance to the battery if the battery were not hooked up to the motor and it was not submerged one of those people could have killed themselves if they had grabbed one terminal in each wet hand. It is the current that will kill you. I have heard of a case where a man killed himself with a 9volt alkaline battery (punctured skin on each hand with battery terminals current stopped his heart! sounds like Darwin in action. http://www.rccaraction.com/ubb/smile.gif
Enough of this typing stuff I'm going to go and DRIVE my car (indoors on dry carpet http://www.rccaraction.com/ubb/smile.gif)

[morfeeis]

who makes waterproof stuff

[TufferWilde]

OK guys - I went out and tried it on an older motor last night - it did not seem to harm the motor.

Everyone saying that water is not a conductor in its purest form, you are correct, but the chances that anyonw would find water in this form is rare. Bear in mind however, that we are incredibly conductive and electrical damage to nerve tissue is not a comfortable method of injury, not to mention the fact that an electrical charge can cause any muscle in your body to contract to the point that it will tear - this includes cardiac tissue (heart) - in other words, don't mess with large electrical sources and water - they do not mix will.

[doublet]

OK I asked my chem teacher. Water IS A CONDUCTOR ONLY AT HIGH VOLTAGE such as 121 volts. Thats why you DIE if you threw a turned on hair dryer in the tub you're sitting in. BUT 7 volts isnt enough to harm anything because once before i ran my xx4 in a full drainage ditch and the battery and speedo came out just fine. AND people at my hobby shop sometimes break motors in under water. I thought it all made sense. If you dont believe me take an old ccrappy battery and charge it and throw it in a puddle or sumthin and nothing will happen.

[cpuman]

Try the new issue of car action magazine they have a whole break down in there of how to get the most of your motor.

by the way it includes putting it in water!

[Nairb]

Yep! I saw that, too. http://www.rccaraction.com/ubb/smile.gif

[DJ BlendeR]

Which issue is that? I am getting so peeved. I got a subscription way back in december and I have gotten nothing. SO anyway to the original question, which issue, cuz I still need to break in my new motor.

[nrgtrader]

The key to conducting is voltage. Voltage is the force behind the electrons pushing them along (voltage is also called EMF Electro Motive Force), and current (or amps) is the quantative amount of electrons actually flowing. Like a water hose.. how fast the water is coming out is voltage, the amount of water is the current (or amps). It takes more than 12 volts to conduct electricity in water since 12 volts is NOT enough force to push the electrons from particle to particle in the water. PURE water is indeed a very poor conductor.. but with 12 volts of force, so is tap water. A rule of thumb I alwasy heard was that it takes 10000 volts to make current jump 1" through the air (10KV to make a 1" arc). In the case of breaking a motor in, the water is merely a lubricant/coolant aiding in the cooling of the brushes while they being cut by the comm.

[Crazy Canuck]

Right about the salt, but theres something about AC and DC. When you run DC the electrons move straight along the wire and all the way through the cicuit nack to the beginning, each electron carrying its own charge of X joules. W/ AC power, from an outlet, the joules of power are passed from electron to electron because they bump into each other to move the current. This means the joules (Volts) can move all through the glass. W/ DC the electrons will follow the path of least resistance, through the wire. So the motor will only short out in a very concentrated salt solution, not a weak one. Hope that helps

PS Dont run a motor in salt water salt is corrosive and rusts contacts not a good situation

[jrob440]

Very interesting topic. Another factor to consider is that the conductivity of many solid objects changes when they become wet. Skin, which normally does not conduct electricity very well, will conduct much more readily when wet. This is why high voltage and water are dangerous. Most metals and many other elements also become more conductive when wet. The voltages in RC cars are really not high enough to have any effect on the motor or battery. The speed control and the receiver, on the other hand, have capacitors, potentiometers, and resistors with very specific conductance properties. If these items get wet, they can be damaged.

[oneflewover]

DJ Blender, it's the April 2001 issue.

And I think that the post before this one is important because of the AC/DC differences...

but that's just a foggy remembrance from high school electronics class!

[Car_Head12]

i dont think it really matters...

everybody is gonna think somethin different...its what works for you, not some crazy pyro ( jp, u da MAN!! ) or some person who is to stingy to put their motor in some water.

now back to the ORIGINAL question, yes, it will work, BUT like the magazine said it WILL ONLY WORK with AC or DC ( cant remember which one ).

CAUTION:hairdryers are very dangerous http://www.rccaraction.com/ubb/smile.gif http://www.rccaraction.com/ubb/smile.gif

Car Head

[Andy]

As I was quite interested in the science classes at school I think I can bring some light into all this:
At about 7 volts water will almost not conduct any electricity this means only a very small current will be present when you submerge your battery.This will not harm it as it is used to currents in the 30 A region. Still if things like a receiver or an ESC get wet (inside) this may harm them because they use only very small currents in the first place.
+So if you run your car through a puddle of water and your receiver gets wet you will most likely experience radio problems until the receiver has dried. Afterwards it should be fine again. If however you are unfortunate the water i.e. the current it carries , can damage some of the internal componenets of the receiver - making a repair necessary.

[Grant Tokumi]

Since this thread is picking up interest again, I thought I'd mention a little experiment I did.

Executive summary: normal servo will be damaged in water.

I hooked up a radio system with receiver, 4 AA alkaline reciever battery, a Futaba S3003 servo. I hooked up a volt meter to the receiver battery to monitor the voltage. I dropped the servo into the water for 5 seconds, and the thing worked normally. Not trusting that result, I proceeded to take off the covers and drill couple 1/4" holes in the servo case to allow water to freely flow through. Dropped the servo in, tried to turn it and it immediately started glitching big time and voltage slowly started going down. After like 5 seconds, servo stopped moving completely. Kept it in for maybe 15-20 seconds and voltage drop started to speed up, so I took it out. Servo didn't work anymore. I wanted to take it apart to help it dry out and see if it might work again, but upon removing the insides, the potentialmeter (sp?) came apart. I guess the board holding it together got wet and soft and came apart. I tried to put it back together but ruined it in doing so. Oh well. At least now I know first hand that the servo won't work underwater. Next step is to dip the receiver. Didn't get to that point yet.

[SteveP]

Grant - don't try your electronics underwater - they'll be toast. There are other components in the servo besides the motor that DON'T like water at all.

As for the motors, everyone's input has been great and best of all, civilized. I think however that were taking a simple question and turning into an overblown and unnecessary debate. We don't need to turn this into rocket science - save that for the really tough questions.


Yes, you can dip and R/C electric motor into water for break-in without any adverse effects. The effectiveness of the break-in is another issue, but no harm will come to your or your motor by BRIEFLY dipping it in water to accelerate the break-in process.

Now wasn't that easy?! http://www.rccaraction.com/ubb/biggrin.gif http://www.rccaraction.com/ubb/biggrin.gif