Confused: Running the Ul-1 below max speed

[hyrulejedi86]

So, I was reading this post from last year:
http://forums.offshoreelectrics.com/...ead.php?t=9691

It kind of confused me. It kinda sounded like you can't run the UL-1 at all unless you go full or near full throttle for a couple minutes the pull it back in.

What if you can't run the boat at full speed due to waves or just wanting to go at say half throttle to get used to the feel of the boat? I often like running my boats slower than full at times if I'm just messing around with a friend in close proximity and not racing or anything like that.

Was this due to the 3700mAh batteries mentioned in thread or does it apply to any batteries? Even the 5800mAh 30C 2c Lipos I want to get when I get my Ul-1?

Thanks in advance for the clarifications!

[Fluid]

The limiting factor is the ESC, not the cells. You can run around at part throttle all the time, but it could cause overheating of the ESC. If you want to run slow, use a smaller prop so that you can keep the throttle pegged most of the time. Of course it is just fine to run at part throttle some of the time. A recent thread discussed this very topic.


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[Grimracer]

BTY.. its not JUST the UL-1.. its all FE boats

Grim

[Steven Vaccaro]

I was told to think of it like this.
A esc is a like a switch. Off is when the esc is stopped, on is at full speed. Then in between(partial throttle) the switch is opening and closing thousands of times at varying speeds depending on the throttle position. That switching causes heat and inefficiency.

[hyrulejedi86]

I see, that's interesting. This is new to me. So, if say I replaced the ESC with say the Seaking 120A ESC with watercooling, would it help this at all? I would imagine based on your responses that it would still get warm but maybe not as warm since it can handle more amperage.

Just a thought.

[bigwaveohs]

The ESC is more like a rheostat...at full throttle most all the voltage drop is across the motor which takes most all the power. At half throttle, let's say about half the voltage drop is across the motor and half is across the ESC, so the ESC is going to be absorbing more of the battery power and begin to heat up...power dissipated is volts x amps, so the more voltage you drop across the ESC, the hotter it's going to get. A larger ESC will be able to handle more power, but watts are watts, so it's still going to have to dissipate the same amount of heat at half throttle as the smaller ESC...it will still get hot.

[hyrulejedi86]

I see, I guess I'll have to monitor how I run my UL-1 and make sure I don't overheat anything.

[hyrulejedi86]

Fluid, you recommended a smaller prop to run slower when desired, what would you recommend?

Grim said in a different thread "Update to the Grimracer 36X55 prop.. I still find this about the best over all prop for the boat."

Why is this the best overall and would this meet your smaller prop recomendations?

[Grimracer]

38X55!

Its a great prop for sport running and racing.

Grim

[hyrulejedi86]

Why is it such a good prop? I'm just curious. Does it help with the heat problem at all?

By the way, I appreciate everyone's prompt responses. I'm glad I found this info now before I get the boat!

[hyrulejedi86]

Also, in addition to the previous question I was wondering if adding another capacitor to the Ul-1 ESC is still necessary since it was upgraded with a bigger one in the second version of the boat?

Then I was wondering what benefit does this provide? Why do it?

Thanks

[pescador]

I have a first generation UL-1 and puffed the original capacitor by running in the wind at less than WOT.
I've since replaced it with 2 bigger ones and haven't had any problems. I don't know if it cures it completely but it sure is nice just replacing a cap instead of an esc.

I'm running the 40x52/3 on both my UL-1 and VS1 I'll have to try the 38x55.
Grim rocks!

[hyrulejedi86]

Oh Ok, Well what causes the puffing? I wonder if the second gen is still recommended to add it in.

[pescador]

It wouldn't hurt, higher power boats add banks of them like these
http://www.offshoreelectrics.com/pro...035-lv&cat=136

but probably not necessary with the new cap it looks a lot bigger.
I just look at it as extra protection for the esc.