Stupid electrics

[Sixtysixdeuce]

So on Sunday I'm up at the indoor track, running my Prolite, when suddenly the ESC just poops the bed. Mind you, we're talking about a 6S rated 150A 1/8 scale ESC running on 3S in a 1/10 scale truck, had maybe 30 packs through it. Aggravating, but oh well. Decided that instead of ordering a new ESC for that truck, I'd just take the 150A Dynamite sensorless ESC out of another and buy an Orion Vortex 2,000KV take-out for only $50. The new motor showed up yesterday, so I quickly installed it, decided to do a short test run while there was still some light. There's snow on the ground, but the roads are hard packed, so it wasn't like I was going to bury the thing in a snow bank. Should be OK, right? Wrong! In just a couple of minutes, a tiny amount of moisture found its way into that ESC and smoked it.

That's four ESCs smoked in this truck since I bought it new in October. None of them have been pushed beyond their ratings. The first two were the stock SC900 Associated ESCs with the stock 550 motor; after that, I bought a 1/8 scale sensored combo (Beeman) for a great price, figuring that the light weight of the truck and the fact that I was only going to be running 3S and maybe 4S on a 6S rated system should provide long life, despite it being a cheaper combo. Wrong again. Now here I sit, waiting on the last ESC I'll ever buy for this truck, a Hobbywing SC8 WP, 120A/4S rated and allegedly waterproof.

I tell ya, if this one cooks before I deem it acceptable, this truck is going to be converted to nitro, and I'll be unloading every other electric, save for my original RC10. I've just had it with buying ESCs that crap for no good reason. Doesn't seem to matter how much or little I spend, how careful I am not to exceed the ratings; none of them last very long. Hobbyking, Hobbywing, Associated, Venom, Dynamite, Novak, LRP-all of them have died early deaths for no apparent reason. Only 6 of my kits are electric, but in less than a year, I've been through no less than a dozen ESCs and a couple of motors.

Today I decided to cheer myself up running my bone stock MGT 3.0 around, and not worrying about bashing it through deep snow and absolutely drenching everything. 2 tanks later, I had my fix, and the truck is just fine.

So I say it again: Stupid electrics!

/rant off

 

[chickenman242]

there is something very unsatisfying about smoking an esc , I had flames come out of my mmm in my e maxx after 6 run not bad considering I paid nearly $1k for the truck

 

[aMawds]

Glad I decided to go with the smelly, messy, prissy little nitro's I suppose Does it suck when it refuses to start for no apparent reason? Yes. I always figure it out though and because of the additional challenges, I always have a bigger smile on my face when it cooperates with me. Leave electrics for the airplanes and heli's. Nitro is just plain more fun.

 

[smittyzz]

You know you should be converting all your electrics sixty!! A true nitro head can't run electric
The issues I'm having are frying every servo I had with water Lol. I've got left out of 6, I've got waterproof ones on the way, and first change I get I'm getting some 313s to try out. I can get a pair shipped from the us for 18!
I NEED WATERPROOF! Lol

 

[HPIguy]

How many cells the ESC is rated for is simply telling you the max input voltage that it can handle. But it tells you nothing about how many amps the motor on the other side of it is capable of asking for, and the motor in an electric rig is in charge, always. For example, if you have a motor that can demand 200a, and an ESC that can only provide 100a, then the ESC will attempt to hand out what the motor asks for, letting the magic smoke out in the process.

Being over-geared (too tall a ratio) can also cook electronics as they struggle to get the rig moving, sucking a ton of amps and generating a lot of heat in the process. Also, the more voltage you add as you increase cell count, the more heat that is generated as a waste product, so the old saying of volt up and gear down holds true as well. What temperatures were you seeing on the ESCs that have let go? It sounds to me like either they're getting cooked, or overloaded to the point of failure.

12 ESCs in less than 12 months is not normal by any means. I have brushless ESCs that are five years old and still going strong. As far as waterproofing, it's cheap and easy to do yourself using products that are made for that application.

 

[smittyzz]

I have waterproofed at home, but didn't use grease in the top gear case, that was my flaw.I might get some grease, but considering the fact that I plow threw over and all around snow, I would rather be safer using one made waterproof.
But back to subject, that makes since on the supply and demand!

 

[Sixtysixdeuce]

How many cells the ESC is rated for is simply telling you the max input voltage that it can handle. But it tells you nothing about how many amps the motor on the other side of it is capable of asking for, and the motor in an electric rig is in charge, always. For example, if you have a motor that can demand 200a, and an ESC that can only provide 100a, then the ESC will attempt to hand out what the motor asks for, letting the magic smoke out in the process.

Being over-geared (too tall a ratio) can also cook electronics as they struggle to get the rig moving, sucking a ton of amps and generating a lot of heat in the process. Also, the more voltage you add as you increase cell count, the more heat that is generated as a waste product, so the old saying of volt up and gear down holds true as well. What temperatures were you seeing on the ESCs that have let go? It sounds to me like either they're getting cooked, or overloaded to the point of failure.

12 ESCs in less than 12 months is not normal by any means. I have brushless ESCs that are five years old and still going strong. As far as waterproofing, it's cheap and easy to do yourself using products that are made for that application.

I know how to do the math.

When a 1/8 scale ESC rated for 6S with 120A continuous and 760A burst can't stand up to 3S on a 2150KV motor in a 6 pound 1/10 scale that was geared according to KV (stock is 3,500 KV with 14/47 gearing, I was 2150 KV with 20/47 gearing), there's a problem.

When a 3S 60A continuous rated ESC can't take 2S with a 4,000 KV motor geared 18/81 with a 2.25 trans ratio in a 3-1/2 pound buggy, there's a problem.

Maybe the issue is that I don't give them a break. But that was the whole point of using ESCs that are rated far above what I'll be asking of them. Regardless, I don't have to give the nitros a rest; I can run them non-stop until I'm out of fuel, receiver packs or daylight, whichever comes first.

 

[hulkmaxx]

True Dat brother, I just recently got into the scaler side of the hobby and it's fun as crap other than the scalers you will never catch an electric in my hobby room. NITRO!!!! ALL THE WAY!!!:whhooo:

 

[hotrodrob]

Go nitro.......id much rather smell burnt nitro as aposed to burnt electronics, hahahaha

 

[hamz9561]

Just as in nitro, you get what you pay for with electric components. There is a reason that they are cheaper (like all of the components being of a lesser standard). I am leery of anyone that claims their $5 part is every bit as good as a $50 part that is known to work.

 

[Sixtysixdeuce]

Just as in nitro, you get what you pay for with electric components. There is a reason that they are cheaper (like all of the components being of a lesser standard). I am leery of anyone that claims their $5 part is every bit as good as a $50 part that is known to work.

You consider Associated, LRP & Novak cheap?

I've been having failures with the expensive makes as well as the cheap ones. Only one I haven't tried yet is Tekin. Only thing I can think of is that they all need "breaks", which is hogwash, IMO. If they can't handle continuous use within their ratings indefinitely, they can go away.

Incidentally, the only ESC I have that has seen a lot of use with zero glitches is a Hobbywing SC10 pushing a 10 turn motor on 2S in an RC10T geared 19/87 with a 2.25 stealth.

I just recently got into the scaler side of the hobby and it's fun as crap other than the scalers you will never catch an electric in my hobby room.

I've been thinking about a 1/8 scaler, but not electric. MGT 8.0 trans and an OS FS90 is what I have in mind. How cool would a 4 stroke nitro scaler be?

 

[hamz9561]

I was actually thinking of the Chinese knock-offs that are everywhere on the net.

 

[SMaxxin]

You consider Associated, LRP & Novak cheap?

Maybe not cheap in price but I wouldn't buy any of those brands. The Associated and LRP (I'm pretty sure they are the same company) have always seemed weak to me, they never put out what they should and are always slow IMO. Novak was great back in the day but the newer stuff is known for burning up pretty quick.

 

[aMawds]

Just saying, I built up a great 450 heli with a turnigy ESC and other "cheap" electrics. One of my turnigy's went underwater for a couple minutes before I got to it and unplugged the battery. Still works a year later. In this hobby quality one year is cheap garbage the next. Companies build up a brand then cash out by selling cheap crap for hugely inflated prices when they aren't making enough money on quality alone. Meanwhile turnigy has been building their name but most of their stuff is still cheap. Try a turnigy ESC as a last resort.

 

[Sixtysixdeuce]

The Associated and LRP (I'm pretty sure they are the same company)

Always been separate companies, but AE was the US distributor for LRP. They parted ways last year, in August I believe.

Have had really good luck with both AE and LRP nitro engines, but not so much with speed controls (no complaints on the Reedy motors, though).

Try a turnigy ESC as a last resort.

Maybe I will, they're certainly affordable enough. Given my experiences, I'm pretty sold on the Hobbywing stuff. Reasonable prices, and thus far the only ones that haven't given me issues. Only have two of their ESCs at the moment, and the 60A in my wife's B3 has seen very limited use, but the reviews are generally glowing. The 10T motor in my RC10T is a Hobbywing EZrun, and I have a 13.5T Xerun sensored en route for one of my buggies, as well as the SC8 WP for the Prolite.

Despite more and more people going with electric, the durability issues have pushed me the other way. I go to the local indoor almost every Sunday, and every single time, at least 2 or 3 people (out of usually about 20 present) are having ESC issues.

We'll see if these next couple of HW items do as well as the stuff I already have. If they prove themselves, my final electric build will likely be the conversion of my second 801XT with a Xerun 1/8 set up. If I have any issues, though, that second truggy will probably get an OS .28XZ.

 

[SchrodeMode]

I know how to do the math.

When a 1/8 scale ESC rated for 6S with 120A continuous and 760A burst can't stand up to 3S on a 2150KV motor in a 6 pound 1/10 scale that was geared according to KV (stock is 3,500 KV with 14/47 gearing, I was 2150 KV with 20/47 gearing), there's a problem..

I'm not too experienced with electrics but doesn't "under" gearing a rig put the stress on the ESC while "over" gearing puts it on the motor? What temps were you getting from the ESC and motor?

Sent from my GT-I9300 using Tapatalk

 

[Sixtysixdeuce]

I'm not too experienced with electrics but doesn't "under" gearing a rig put the stress on the ESC while "over" gearing puts it on the motor? What temps were you getting from the ESC and motor?

The wisdom that applied with brushed motors and mechanical speed controllers simply doesn't with brushless.

An old mechanical speed control is nothing but a variable resistor; rather than allowing a specified current to pass through, it is restraining voltage and current, dissipating excess as heat. Running them part throttle makes temperatures climb, which is hard on the resistor.

With brushless, you have a bunch of solid state N-channel power transistors that switch on and off to pulse the coils of the stator. The harder you run them, the hotter they get from faster switching and higher current loads.

Over gearing will strain any system, electronic or combustion. But unlike a combustion engine, which will simply stall if the load is too high, an electric motor will continue to receive current-even if it is not turning. Lock your wheels down and hammer the throttle, you will let the smoke out of either the speed control or the motor (or the power cables, whatever is the weakest link in the system).

What will make under-gearing hard on them is not the load, but the constant high RPMs and fast transistor switching that results from trying to attain speeds that would be done at a more moderate RPM with proper gearing.

 

[SchrodeMode]

I understand that the strain will be on both. I'm just talking about the simple "if the motor's hot, gear down/if the ESC's hot gear up"....at least that's what I was told. If that's not true, I'd like to know because that's what I was told and what I'm following.