Power delivery VS End Point

[Wooders28]

My 5yr old daughter announced the other day, she wants to race with daddy next year, result!!

Suggested to the Wife, the idea of getting a new car for me, and giving her my old one, unfortunately her memory is good, and asked what happened to the car with the blue body, that I raced before that,  the one that's in the box she moved in the garage the other day.....busted😬

So, she's got a Schumacher KF2se to run, choice of sticks or wheel, it's the choice of motor I'm wondering what to do.

She's run my 6.5t Laydown, and did well ,resulting in her upto 35% on the throttle end point.

Now, I've the choice of a Hobbywing 13.5t or a Speed Passion 6.5t to put in her car (without buying another motor). A 6.5t (without timing) are around 6700kv, and a 13.5t around 3500kv, so 35% of 6700 is 2345.

So-  Would running a 6.5t at 35% be better , worse or no different from a 13.5t at 70%, ? 

Pros and cons? 

[Jonathon Gillham]

You don't have any stock type classes over there like 17.5T buggy do you?  I set my son's cars up to run 17.5T stock and run his EPA about 65%, but its increasing all the time.  That way I can grab them as a spare car when I need them (also, realised that I should put decent gear in there, last time I used his car I was 2 laps slower than with my car so not all 17.5T's are created equal!).  If your car breaks can you run a 13.5T and keep up, or will you be well behind?  

I have also heard, but can't remember where, that using EPA to limit the speed isn't ideal, something about how it does it and it can overheat the ESC or something?  I don't know, can't remember, but I have been limiting my sons cars for years without issue.
 

I guess this is a waste of time, as my gut would say run the 13.5T and slow it down less (it just seems right) but I haven't experienced any adverse effects on motor, ESC or rx over 3 years now of using EPA to slow down Jamie's cars, so you'd be better with the 6.5T as then you can use it as a spare car?

[Wooders28]

49 minutes ago, Jonathon Gillham said:

You don't have any stock type classes over there like 17.5T buggy do you?

No, just 2wd and 4wd. Actually works quite well, as you'll be in races with drivers of a similar skill level anyway, and there's no cheating, as you can run whatever motor wind with as much boost/turbo as you want.

Not heard anything about it damaging an esc, I thought they all ran on Pulse Width Modulation anyway, and the signal is from the radio. It's not like there's a resistor to heat? 

Spare car could be handy! What I don't want to do, is be in a situation, where she's having a good day, and could run quicker, but the end point's at 100%. The ESC will be a 10bl120, so no boost / turbo...

[Jonathon Gillham]

4 hours ago, Wooders28 said:

No, just 2wd and 4wd. Actually works quite well, as you'll be in races with drivers of a similar skill level anyway, and there's no cheating, as you can run whatever motor wind with as much boost/turbo as you want.

Not heard anything about it damaging an esc, I thought they all ran on Pulse Width Modulation anyway, and the signal is from the radio. It's not like there's a resistor to heat? 

Spare car could be handy! What I don't want to do, is be in a situation, where she's having a good day, and could run quicker, but the end point's at 100%. The ESC will be a 10bl120, so no boost / turbo...

Yeah it would work better than motor of the month and charging at 30amp for any edge (doesn't happen at my clubs luckily). Stock classee have the benefit of less breakages though

Thinking about it more, I would go the 6.5T. I don't think a 13.5T will be too slow anytime soon, but you'll have the right gearing etc for a 6.5T motor already

[Wooders28]

15 minutes ago, Jonathon Gillham said:

Thinking about it more, I would go the 6.5T. I don't think a 13.5T will be too slow anytime soon, but you'll have the right gearing etc for a 6.5T motor already

I'm edging towards the 13.5t now...🤦‍♂️

Wondering if she starts on 70% then, move to 80, 90%, she'll feel like she's making big progress.

Guess I could keep an eye out for a 10.5t speed passion, they're on plugs, so easy enough to swap out....

[DeadMeat666]

With my admittedly super-basic knowledge of all things electrical, I generally believe that it's probably not a good idea to run an electric motor below 20% all the time, as it tends to be inefficient at such low power levels. Setting EPA at 35% for a 6.5 turn means the motor will be spending most of its time in that inefficient area. My gut tells me that 70% on a 13.5t is a better idea.

For reference, my gut is often more intelligent than my brain; this is either a compliment to my gut or an insult to my brain. You decide.

[Wooders28]

11 hours ago, DeadMeat666 said:

tends to be inefficient at such low power levels. 

Is that a bad thing? Does that mean it'll be less aggressive? Which is good. Or just use more battery than a differnet wind? As long as it lasts 5 min, I'm not that bothered.

11 hours ago, DeadMeat666 said:

my gut is often more intelligent than my brain; this is either a compliment to my gut or an insult to my brain. You decide

You're onto something there!! 😂😂

 

In pretty much all my cars, I run more power than I think I'll need, and turn the electronic magic witchcraft down to peak enjoyment, make mods and adjustments, and readjust. Am I applying the same logic to my 5yr old?, when she'd be happy with a 13.5t ,and up at 100%? 

[CoolHands]

I think the 13.5 would be plenty. I run 10.5 and it’s quick enough, and most young kids were similar in speed so I can’t see you’d need the extra for her for a couple of years at least. I also think they would run better being higher up the % range than a quick motor at 35%.