Theoritcal CC Motor Gearing Questions
 

Alright. Lets talk motors and gearing.

For all examples, the battery is 4S 30C 5000mah.

Vehicle weighs ~14lbs.

Stock motor and esc is a CC MMM 2200kv combo.

Stock gearing hits 40mph with a 20t pinion.

If one were to purchase a 1518, 1520, or 1717 motor, what would happen if the vehicle were geared to still hit its 40mph top speed while using the same battery?

Table: Motor and Pinion required to hit stock 40mph top speed.

1515 1Y 2200kv motor 20T pinion

1518 1Y 1800kv motor ~25T pinion

1520 1Y 1600kv motor ~28T pinion

1717 1580kv motor ~28T pinion

The three choices all have significantly more torque than the 1515, but will they be able to over come the added strain.

Will they pull more amps to do so?

Will they over heat?

Thanks

I saw Bondo recently say the 1717 is an amp hog. Given that I would say the 1520 would be the most efficient. Longer motors generally run cooler geared for the same speed.

I'm switching to a 1518 in my truggy and a 1520 in my Savage 5T. I'll be running on 5S/6S.

I'm switching to 1518 in my truggy also. Either a 1520 or 1717 in my DB17.

Still wondering about what would happen on 4s geared up.

Well, bigger pinion on bigger motor means nothing in terms of "extra gearing".
The longer motor produce more torque for the same current, so geared for the same speed the current will be theoritically the same.
In the reality, the current will be a little smaller in the longer motor, as it's run more efficient (less magnetic losses as it spins slower, less heat as it handle the same power in a longer can...).
But this is true if the widings are the same, which the case between all of thoses motors (1 turn star widings).
So don't be worry using bigger pinions on longer motor ;)

Hello
I didn't want to start a new thread in the same subject. I am wondering about the same question, but not from the theoretical point of view:
Did someone actually try the 1717 or the 1518 geared up for about 40MPH with 4S 5000 mph (or so) Lipo in his truggy ? any conclusions? (amp draw, run time, temperatures ?)
Thanks
Billy

Once mine gets here, I'll be able to comment on my own question. :)

I try a 1520 on 4S in my buggy instead of a 1515 on 4S. I have lower temps and a little more run time, which is logical, the longer motor provides better efficiency (same windings and design).
The 1515 was about 42°C at run end, and 1520 was about 34°C...

Both were geared to hit the same top speed?

Of course ;) 13/46 vs 18/46

Thank you very much. That is the exact kind of info I wanted to hear. Maybe I won't have to run 5s in my truggy. Only needs to hit 40mph for racing. I planed on running the 1518 in it, but I may trying out my 1520 also.

The 1717 will still be going in the Flux.

I Will try my 1717 when it comes. I am very curious to see what will be the temps, the amps draw and run time if geared to hit 40 mph (about 19/46) with my 4S Lipos on the rc8t-e. I anyone here have any news to me also - I would like to hear

Don't forget that the 1717 is a lot heavier than the 1515, 424g vs 570g, the efficiency gain can be therefore minimal.

But how much more power does the 1717 make versus the 1515?

Maybe it can't be geared up even more due to it having more torque.

Yes, but if you gear more in an heavy vehicle, that's the ESC which will suffer a little more. The danger is that your motor temps will be colder than the 1515, so you will want to gear it up a lot...
Anyway, nothing replace the test, with checking the motor and ESC temps every minutes the first run :smile:

Yeah, this will be fun. Especially since they finally paved the road in front of my house. No more deadly man hole covers to avoid at 50mph.

I put 1 of my 1520s in my SC8E.I will be using a 5s 40c battery 21t pinion.This seems safe?I also have a 1717 yet to try also in the SC8E also 5s.

The info I have is:
The 1717 seems to be 2000Watts (4000w surge).
The 1515 is 1250W (2500w surge).
The 1518 is 1500W (3000 surge).
The 1520 is 1750W (3500W surge).
Anyone with info on temps and run time on 4S Truggy Geared to 40mph - is welcome :-)

I am runnin 5s though.

Yeah, and its a SC-8 and not a RC8 truggy (which I believe is heavier). Not an exact comparison, I would say...
(in my language we have a phrase: "we should compare apples with apples").
Because I already have good (and expensive) 4S packs - I am less interested in a data which relates to 5S packs (again - not "apples with apples").
:smile:

I really didnt want to start a new thread to address CC flood of low kv 1500 series and the 1717 into our projects.

No problem. This thread is fine for all low KV motor questions.

BMR4life - any news? please share...

None yet. Finishing up getting the 1717 in my flux. I'm waiting on a set of pinions for my truggy, then I'll put the 1800kv in it.

Well, I have news:
I installed a few days ago the 1518 (1500 Whats, 1800 KV) in my Truggy (RC8t). I am running my truggy 4S Lipos (Thunder power - 5200mah, 50C, Team Orion 5100mah, 40C).
This motor is a monster!
The 2200KV was geared to 14/50 (about 60 km/h), and the 1518 is geared to 18/50 (about 63 km/h).
The 1518 has noticeably more power than the 2200KV (which was installed earlier), it runs cooler (the motor reached 70C but it was after a very hard bashing session in deep sands. With the 2200, I had to stop every 7 minutes for cool down).
The run times were about the same (maybe a bit shorter with the 1518).
I am very happy with this upgrade :-)