Temps with new water jacket, new pickup and larger tubing

[ms71171]

I just got my heat gun and wanted to bounce my temps off you guys.

After a full run with moderate wide-open time on my 20C 5000Mah Turnigy LiPos, I had a ESC temp of 156 degrees. and motor (stock) temp of 126 degrees.

This is after I re-plumbed my stock pickup and lines to run only to my ESC and add a new pickup, water jacket and output for my motor.

Seems like my ESC is pretty hot. I'll drill out my rudder pickup further I guess, or is 156 OK for an ESC?

[osprey21]

IMHO, 156° is rather warm.

[ms71171]

IMHO, 156° is rather warm.

Yeah, that's what I thought. I'm thinking of adding another pickup and doing away or augmenting the stock rudder pickup.

[wizard122]

You need to run the boat at full throtle all the time running it at part throttle will over heat things real fast. Slow down for the turns then get right back on it. What prop are you running? Post a photo of your boat so I can help with your setup OK?

[ms71171]

Grim 42x55. I have a Octura x642 on the way

[ms71171]

I'll get photos up too

[Dale Koblitz]

All I did was ream out my water pickup a little and put some thicker tubing and and mine runs pretty cool. Nothing gets hot anyways. I'm running on 2 2s packs. I don't run wide open all the time either because if I did I'd be spending more time fishing her out of the water. I'm running an oct detonged x443 I believe? Could be x442 I can't remember but it's very quickout of the whole and top speed is very good too. Make sure you have a steady stream of water coming out of the outlets. Maybe something's plugged up?

[ms71171]

Dale, what temps are you getting exactly? I don't have and blocked lines and have also moved to larger tubes.

I think my temps are probably from running half throttle in the temps I reported above. Since I've changed my prop to a x642 the temps have gone down on my motor and my esc.

[Meniscus]

This may be a silly questions, but just to make sure: you're running the water cooling to the ESC first right? Then to the motor?

[ms71171]

This may be a silly questions, but just to make sure: you're running the water cooling to the ESC first right? Then to the motor?

Actually, I have dual lines. One using the rudder pickup to my ESC and a transom pickup for the motor.

[ggcrna]

Would someone please explain the logic behind partial throttle resulting in MORE motor heat?
Seems counterintuitive to me.
My understanding: high revs = more heat , low revs = low heat.
Or are you talking about the higher speed moving more water flow thru the cooling tubes ?
thanks,
G

[Diesel6401]

Would someone please explain the logic behind partial throttle resulting in MORE motor heat?
Seems counterintuitive to me.
My understanding: high revs = more heat , low revs = low heat.
Or are you talking about the higher speed moving more water flow thru the cooling tubes ?
thanks,
G

my take on it is like a combustion engine is designed to go full throttle not partiel. I compare it to highway driving vs city driving city driving. City driving (on & off throttle) is more hell on a system then highway drivng (continous constant rpm). JMO, im idiot though.

[m4a1usr]

Would someone please explain the logic behind partial throttle resulting in MORE motor heat?
Seems counterintuitive to me.

Why is partial throttle bad? Well,........first you need to know how an esc works. It takes a constant voltage source (your battery pack) and changes that to an analog voltage to your motor. So that as the throttle position varies so does the voltage to the motor. This is done by turning on and off the FET's in your esc. A FET is a low-resistance switch when fully turned on. When it's not fully turned on, it has a resistance which varies depending on exactly how turned-on it is. This is called the "linear mode." When in linear mode, a FET is like a big resistor - you know, those things inside your slot car handle that get HOT, or like the ceramic thing in your old mechanical speed control. The problem is, FETs don't like to be in linear mode - as they warm up, they become more and more resistive. But the motor at low RPM is less and less resistive, meaning it will draw more current.

So heat increases in the esc FET's when less then full voltage is applied because its operating in a less eff. manner. Thats the simple explanation. There is a more scientific way to describe it but I dont feel like typing it right now. Besides the information has been posted several times here on OSE.

John

[Diesel6401]

What he said.

[ggcrna]

Thanks John for that explanation.
I get it now.
Glenn