Brushless Motors

[Stu74]

I am probably getting a bit ahead of myself as i havnt even ordered my 1st car yet (probably a db01).

But when the time comes to upgrade the motor i dont have a clue what things mean like 9t or 5.5t.Is the lower the number the faster the motor?Also buying the motor with a suitable brushless esc is a bit confusing aswell.What is better a 60amp or 35amp?Does the 60amp drain the battery faster?

Its all a bit foreign to me at the moment.Any explanation would be helpful.

[Mighty flex]

lower number is a faster motor. the 5.5t ezrun is a 6000kv motor - 6000 rpm for every volt supplied on a 7.2v battery pack thats 7.2*6000= 43200rpm. the 5.5t denotes it is a full 540 size motor, whereas the 9t (no .5 on this one)is a 380 sized motor (hence slightly less torque) inside a heatsink that makes it sized in total dimensions. it is a 4300kv motor, hence you are looking at around 2/3 the speed of the 5.5t. BUT the 5.5t needs more current than the 9t due to its higher power. so it will drain your battery quicker, or if your battery isnt very high capacity or of low quality it will not be able to ssupply the current th motor is trying to draw. This leads to unsmooth operation (cogging). Once you have a battery that can supply the current you need to have a ESC that can cope with the current - the 9t willl draw up to around 30A, hence is packaged with a 35a esc, whereas the 5.5 draws up to 50 or so, so needs the 60a. this is on 7.2/7.4v batteries

once you decide to start using 11.1v batteries your motor will draw more current (and produce more power) so you find your self needing a 60a esc with the 9t... or you end up setting fire to your35A one like i did.

Motor choice depends - 5.5 t is very fast, and 9t is plenty enough to break lots of bits if you crash

I would reccomend paying a little bit more for the 60 version typically as little as £3 extra, because you will have the extra safety of not stetching your esc. Also good if you upgrade your motor later

[Stu74]

That has made things a lot clearer for me.Thanks Mighty Flex.

So if i decide to go for a 9t motor for instance and stick with a 7.2v battery what mah rating battery would be adequate to give me a decent amount time racing without it going flat quickly.

[Mighty flex]

well. I used a 2700mah team orion nimh, with a ezrun 9t, and i was getting good performance and battery life simular to when i was on the stock tamiya 540 in my DF02 - I would say this is the lower limit for a good run time and good punch (response and quick acceleration, which requires bursts of higher current). Given that good quality high capacity nimh batteries can be had for not much more than lower capacity batteries - I have not looked out at batteries like this recently but i have heard good thing about vapextech (on ebay) as good budget batteries ( ijust noticed they also give a good description of the batteries and the sort of current they can supply. pack seem to get more price above 4000mah, but there nothing more annoying than running out of battery cos you only bought a 1800mah nicad!

[PaPeRo]

If you decide to buy new batteries later on, I would recommend you switch over to LiPo batteries. No point in wasting money buying new NiMH batteries IMO.

[Stu74]

My son has 4 pretty new nimh batteries i think the biggest being 3800 mah.So when the time comes when i upgrade my motor i will test it out with this battery and if i find it only lasts for a short time i might look at getting a lipo battery.I would preffer to stick with nimh batteries if possible but i will have to see what happens.

[tamiya monkey]

You will be fine with your nimhs, just will not get the punch due to lower discharge rates from your nimhs, i have a 8.5t ezrun with there 60 amp esc in my slash its quite happy on my nimhs, lowest being 3300mah highest being 5000mah intellect packs, the later being better.

[Power Surge]

You will be fine with your nimhs, just will not get the punch due to lower discharge rates from your nimhs, i have a 8.5t ezrun with there 60 amp esc in my slash its quite happy on my nimhs, lowest being 3300mah highest being 5000mah intellect packs, the later being better.

Yeah, I run my 9T EZrun on 3000mah nimih packs and they are fine. I have the "punch" turned down in the ESC anyway, so the off the line hit from li-po isn't really needed for my setup.

[wolfdogstinkus]

Yeah, I run my 9T EZrun on 3000mah nimih packs and they are fine. I have the "punch" turned down in the ESC anyway, so the off the line hit from li-po isn't really needed for my setup.

I have the 1/18th scale 18T EZrun setup, Is that the same size as the 9T, just the 9T Ezrun has cooling fins?

Anyway the little motor runs on a 2000NiMh battery for well over 30mins.

[Power Surge]

I have the 1/18th scale 18T EZrun setup, Is that the same size as the 9T, just the 9T Ezrun has cooling fins?

Anyway the little motor runs on a 2000NiMh battery for well over 30mins.

No, the 18t 1/18 motor is much smaller. 20mm wide, 30mm long, 2mm shaft. 5200kv rating on that one. Powerful motor, but for a small/light car.

The 9T is 35mm wide, 50mm long, and 3mm shaft. It's 4300kv.

The 9T is basically 380 type internals in a 540 size can. But it runs better than any powerful brushed 540 I've ever had.

[Mighty flex]

the 1/18 set up uses as 20mm by 30mm motor, the next size is a 28x48mm with a 36mm diameter heatsink, and the full 540s are 36x50.

The 1/18 setups are great value too, though i did blow up the 25a running a 9400kv losi motor on 11.1v.

i get a bit scared when i hear 3800mah nimh, are they the sort that come from ebay in sets of 2 for around £13 in green heatshrink with some generic label, and aren't too clever.

[Mighty flex]

nice timing on the posts...

[wolfdogstinkus]

The 9T is basically 380 type internals in a 540 size can. But it runs better than any powerful brushed 540 I've ever had.

Yes, thats what I was getting at, although it's a smaller case and shaft, it has the same power as the 9T?.

I have it in my Qd and it does fly!

thanks for the fast replys.

[Mighty flex]

nope 380 is 28 mm, much bigger and more powerful, but those 20mm ones are still great, and given the fact they weigh basically nothing means you have such a light car (280 size, i don't get the reasoning behind the naming, burshless are more oftnely refured to diameter followed by the length eg 2030, 2848 etc)