Brushless motor suggestion

[Cainam]

As soon as I saw the Summit, I called my LHS and told them to make sure they get one for me. No hesitation at all. Then the thought process started, and I've decided that mine will probably never be run with a brush type motor. I ordered this motor -> https://www.*************.com/*************/store/uh_viewItem.asp?idProduct=6679&Product_Name=KD36-74-15XL_1100kv_Brushless_Inrunner

I'll be using two 2s Lipo packs in series for 4s, and a MMM ESC. The extremely low KV rating of the motor should make it pretty close to the brushed motor it will be replacing, but with a bit more torque. Low amperage, also, so I'm hoping for over an hour of run time. The whole idea is maximizing run time and reliability, and minimizing maintenance and motor failure.

Also, as low as the amperage will be, I can see being able to use two 5000mah 3s packs in series for 6s. This isn't an extreme high speed system I'm looking at, though, but the truck isn't for that.

[killermmn]

man pay a little higher!!

http://www.medusaproducts.com/motors/036-V2.htm

the 70 and 80 version will fit a summit!!

[bentz2151]

i dont know if it wil be waterproof now but then again what do i no

[The Oracle]

If a trail type truck you desire, than a low kv motor is a good choice. I think the 775 motor is rated for something similar to the titans, so a total rpm value in the 25-30,000 region would yield the desired result. That said, even the low kv hobby city motors arent upto much, as Lutach will tell you Im sure. A low kv medusa, or even an outrunner in the 1000kv region would be much more desireable.

[Cainam]

man pay a little higher!!

http://www.medusaproducts.com/motors/036-V2.htm

the 70 and 80 version will fit a summit!!

I understand what you mean, the motors I linked to are cheap. I ran the 9xl version for a while in my E-Maxx, and it ran fine (hot, though) till the truck found a rock it didn't like. The ends on those are screw on, and the fit on the threads is sloppy. It came apart at speed, and the results were, uh, bad. . .

I didn't realize that Medusa made motors in the KV range I was looking for. I already have the 15XL ordered. If nothing else, it will be a great - and inexpensive - way to try the concept of a low KV power source. And I'll be able to see if I need to tweak the KV up or down to get the results I want.

[timaneli]

don´t forget that in the summit is the gearbox that makes the low or high rpm´s and torque... so in my opinion even a 3000kv should be a good motor!!

but i still think that that diff´s and gerabox(with may gears and small gears) aren´t made for high speed´s!!

in my opinion is a great trail truck(maybe the first production one!) and maybe a good basher also, but that only time and runnig will show!!

[killermmn]

i will take a medusa,but i dont know which one i will take!!

[josilver]

if brushed takes a crap its much cheaper to replace!

[Cainam]

I think the replacement brush motor will only be about $5 cheaper than the one I linked to. The 775 size motor by Ofna is on tower for about $27.

[OhmB1Kenobe]

You might want to think again about running the 2 packs in series, that will up the voltage times 2. Parallel will give you twice the runtime if that's what you're looking for. I run 6s in my Trex because of the high voltage requirements, but the runtime is short compared to a parallel setup of the same voltage.

[vxlrocket]

those KD motors are amp hogs and tend to run even hotter than feigaos. i would gear really conservatively to start. :fear:


the more i look at this truck, the more i like it......i had in mind a few HV options for combos...

i was thinking about a 1521 or even a 1527 with a LT-10S or an mgm. with a truck that size, i'd love to see it go on 10S.(not sure if that could be done due to battery compartment restraints) , but it should be a monster on that setup.

[Cainam]

You might want to think again about running the 2 packs in series, that will up the voltage times 2. Parallel will give you twice the runtime if that's what you're looking for. I run 6s in my Trex because of the high voltage requirements, but the runtime is short compared to a parallel setup of the same voltage.

The motor I linked to is only an 1100Kv, so what this does is lower the amperage required by the motor. The expectation on the lower Kv motors is you bring the volts up to keep the R.P.M. the same. Think 3s with a 2200Kv motor should be very close to 6s with a 1100Kv motor of the same overall design.

The 2200Kv motor will draw higher amperage, so lets say you wire two 3s batteries in parallel for it, and the same 6 cells in series for the 1100Kv motor. The power output, r.p.m. and runtime should be very close in theory.

The advantage to running higher voltage is the amperage requirement for the same power output drops, and amps is what generates heat.

The disadvantage to running a low Kv motor on low voltage is that the motor never reaches an efficient r.p.m., which can cause heat problems by itself.

[Chris York]

I have a simple question for Traxxas, What about a Summit VXL.