Brushless, ESC and LiPo #confused

[firefoxussr]

I would say with a chassis as unsophisticated as a TT02... you need 3S, bearings, glued tires, a really good servo and a steady hand/surface.   I've ran 3S on my TT02 and it was a handful (and this was with extra wide tires).   Expect things to break.

[Problemchild]

thanks

i am fully expecting breakages (i habe a full TT02B kit spare)

i'm not expecting to drive full speed everywhere - just would like to surprise people 

in its current state, a drop curb will flip the car anyway

not sure if the ebay specials are worth the punt are they?

i guess i started this thread to see what people are running brushless and i'm getting some good pointers

JJ

[Problemchild]

1 hour ago, Jason1145 said:

I don't think you can beat the cheap EBay combos around at the moment if you want a plug n play brushless motor and ESC... Like these ones here:

3000kv

http://www.ebay.co.uk/itm/SKYRC-13T-3000KV-Brushless-Motor-60A-ESC-5V-2A-BEC-Program-Card-Combo-V4Q6-/262297491681?hash=item3d122618e1:g:m4wAAOSwDuJWxomz

 

 

3930kv

http://www.ebay.co.uk/itm/SKYRC-10T-3930KV-Brushless-Motor-60A-ESC-Program-Card-Combo-RC-Set-C0P4-/272316761218?hash=item3f67580482:g:P1MAAOSwSv1Xkfc0

These come with deans connectors and all motor wires pre soldered so you only have to locate them in the chassis and programme them as you wish ( lvc, punch, drag brake etc)

But these are the smaller 380 sized rotors in 540 size cans so some people don't like to use them, I think they might be ok for these lightweight Tamiya's though, but not in heavier 1/10 short course trucks etc.

just throwing some ideas out there. With of those two systems would be happy on 2s, a GPS top speed recorded and a heat gun are handy tools to have too. ( I've destroyed an Iphone using it as a GPS, never again!)

these seem to be Leopard copies - which as you say are only really 380 motors packaged in a 540/heat sink wrap

the Leopard BLs seem to get good reviews 

looking at LiPos on ebay thats another minefield haha

JJ

[Problemchild]

ok......after hours of scanning youtube and the tinterweb of brushless setups on the TT02B i've made some purchases

(i really shouldn't stay up late along with a credit card!!)

ordered 

1 x Speed Passion V3.0 Competition BL 8.5T  (modelsport £34)

1 x DF02 Parts Bag A (modelsport £20)

1 x DF02 gear bag (ebay £6)

1 x BL 4.0mm male bullet set (ebay £4)

2 x LiPo buzzers (ebay £4)

 

the diff parts are on back order with modelsport so hanging off buying LiPo batteries until next month i think

thanks for all your help guys

 

JJ

[Backlash]

JJ,

What ESC are you going to use?
 

[Effigy3]

1 hour ago, Backlash said:

JJ,

What ESC are you going to use?

I know what ESC he won't (or at least shouldn't) use: the TBLE-02S.  Considering it's only rated down to a 10.5T and that's with the optional cooling fan installed.

[Backlash]

16 minutes ago, Effigy3 said:

I know what ESC he won't (or at least shouldn't) use: the TBLE-02S.  Considering it's only rated down to a 10.5T and that's with the optional cooling fan installed.

Exactly..  (I'm guessing that is the main reason why you suggested that he buy a Speed Passion 10.5 motor in your earlier post..)

 

Maybe he should have bought a Speed Passion Reventon S Motor and ESC combo instead.. It would have been cheaper than buying a motor and ESC separately...  



 

[Nitomor]

For batteries, if you're going 2S I would highly recommend the Core RC 7.4v round stick pack. I have quite a few of these, it fits every one of my Tamiya chassis' with no problems, I also have the HPI equivalent but that is 2mm longer and won't fit all the cars.

http://www.modelsport.co.uk/core-rc-4000mahr-7.4v-30-60c-2s-lipo/rc-car-products/388538

The voltage gives you the power. You'll notice the mah figure for example 4000mah, this is the size of the fuel tank if you like, the higher this figure, the more energy the battery will store. Then you have the 30c/60c figure which is the current rating. 30c means you can discharge the 'tank' at a rate of 30c. 4000mah (milli amp hours) is 4 amp hours. At 1C, you could discharge the battery at a rate of 4 amps per hour. This is rated to continuous current of 30C. It means you can pull 30x4A. In this case 120amps is the continuous current draw with peaks/burst of upto 60c double that. With a 4A battery store, you could draw off 4A and your battery would last 1 hour (4Ax60mins=240amp capacity think of this as the size of your fuel tank). If you draw 8A it will last 30 minutes. With 120 amp draw, you would deplete the battery  in 2 minutes (240amp capacity/120A draw). Looking at your run times will give you a good idea of your amp draw. My WT01 dual Brushless 4x4x4 rig draws around 18A and depletes the battery in 13 minutes. My single motor brushless setups with this modest 9T motor on 2S runs at around 9A and last 27 minutes at full bore battery testing. These are flat out running back and forth at full pelt. In reality, in the field they are lasting double that. With ESC's, the current isn't being held back like with the old msc resistors, so any energy you don't need isn't really used. ESC's use pulse width modulation to control the speed, so rather than holding back an amount of 7.4volts using a resistor to lower the voltage that gets to the motor, they rapidly power the circuit on and off through fancy circuits to achieve the required voltage to the motor meaning much less energy waste,  you may remember how hot your old resistors would get in slow speed running, most of the battery voltage was being absorbed by the resistor, whereas in flat out running the power was flowing straight through to the motor. Brushless motors are far more energy efficient so this prolongs the battery run time even more.

I also use the proper battery pouches (I use the HPI ones) but if you want it to match your battery, here is the Core RC one which is a couple of quid cheaper than the HPI one...

http://www.modelsport.co.uk/core-rc-lipo-locker/rc-car-products/369044

I run HPI flux esc's and brushless motors, I like the 9T can, it is a 380 based system as described and has a very cool finned look which acts as a nice heat sink. I recorded my Hornet at 25mph before running it under a 5 bar gate. That was on grass without a huge run up. I suspect it would be a fair bit quicker on tarmac but that is quick enough for me. I'm quite happy with 2S power and my models have lasted a long time like this without over straining any components. I use Deans connectors and they've been fine. Also I use 2s lipo with the stock silver can on the cars I have with Quicrun 1060 brushed lipo compatible esc's and fit an etronix deans to tamiya interconnector so that I can run either nimh or lipo. The Tamiya connectors on those have been fine but on a brushless system I would be running full deans.

If you look at the old brushed motors, you will see they often quote rpms. I use this rather than the T count to compare. To calculate the rpm on a Brushless motor is simple, 4300kv is say 4300rpm per kv. Running a 7.4v battery = 31,820rpm. You will often see the more powerful motors are lower kv which seems confusing at first, but it is because they are rated to much higher voltages. so a 4300kv on 2s (7.4v) is 31,820rpm, but a 2600kv@14.8v (4s) = 38,480rpm therefore faster so you need to look at kv and voltage rating in tandem and obviously specify an esc that suits the power rating.

You'll need a decent lipo charger too.

Enjoy

Nito

ps. Lipo battery cells are 3.7 volt each. Hence why a 7.4v battery is called 2S, it has 2 cells to give that voltage, the cell and volt count for larger batteries increase correspondingly. Hope that helps, if you knew  most of this already apologies. 

 

[Flerbizky]

1 hour ago, Nitomor said:

My single motor brushless setups with this modest 9T motor on 2S runs at around 9A and last 27 minutes at full bore battery testing. These are flat out running back and forth at full pelt. In reality, in the field they are lasting double that.

Just extracting this from a really good post. With the 9T 4300kv I run in my Blitzer Beetle - I can get bored of the beach with 2 4200Mzh LiPo sticks (:

[Nitomor]

Thanks, I know what you mean, I went with VR detailing to a local bmx track and I took 4 4000mah 2s lipo's with 3 different models and got 4 hours bash time and still had battery juice left over, one usually gets bored or breaks something first. Massive contrast to the days when you got 10 minutes tops and had to wait ages for your next run!!

 

[Flerbizky]

11 minutes ago, Nitomor said:

Thanks, I know what you mean, I went with VR detailing to a local bmx track and I took 4 4000mah 2s lipo's with 3 different models and got 4 hours bash time and still had battery juice left over, one usually gets bored or breaks something first. Massive contrast to the days when you got 10 minutes tops and had to wait ages for your next run!!

 

What - You don't miss those days? One spare battery = $$$$ and 12 hours to charge a 1200Mah battery after using a 12v light-bulbs to completely discharge it (:

[Nitomor]

I must have been one of the rich kids, I eventually got upgraded to a 30 min charger! It kept blowing fuses, so I very cleverly realised that the fuse was just a thin bit of metal making a connection and that if I used a nail instead it wouldn't keep cutting out! Oh lord!!

[Problemchild]

15 hours ago, Backlash said:

Exactly..  (I'm guessing that is the main reason why you suggested that he buy a Speed Passion 10.5 motor in your earlier post..)

 

Maybe he should have bought a Speed Passion Reventon S Motor and ESC combo instead.. It would have been cheaper than buying a motor and ESC separately...  



 

I am here you know haha

confused then as the Tamiya ESC is rated (just @ 60A) past what the max draw of the motor says here...

http://www.speedpassion.net/uploadfiles/downloads/201022516417SPcompetitioinV3_MotorManual_Feb25th2010.pdf

JJ

[Nitomor]

Be careful with power ratings, peak is different to continuous, the esc says upto 60A. The script however says down to a 10.5T which is only 24amp draw. Your 8.5t is a massive 55 amp. But you don't know unless you try, be sure to let us know how you get on

[Effigy3]

2 hours ago, Nitomor said:

Be careful with power ratings, peak is different to continuous, the esc says upto 60A. The script however says down to a 10.5T which is only 24amp draw. Your 8.5t is a massive 55 amp. But you don't know unless you try, be sure to let us know how you get on

Take pictures, and maybe a fire extinguisher?  [Runs off to grab popcorn to await the show.]

[Problemchild]

the motor says "max ampage 55amps" though and the ESC deals with up to 60amps (which will have a degree of safety margin in there)

the tamiya ESC is disposable at £15 anyway

JJ

 

[Nitomor]

I agree, there's conflicting info with the 10.5T limit but give it a whirl and monitor how hot it gets and it may even have a thermal shut down protection anyway. The likelihood is that the motor will run at a third of that amperage in normal use, it'll be how well the esc handles the peaks/loads that'll be the real test. It may well be fine, you'll probably want to change for a lipo compatible esc later anyway so not a lot to lose.

 

[Problemchild]

well its LiPo compatible BUT may look for a better solution when i get LiPos (inc connectors)

i have a laser thermometer for my road car to monitor temps as its highly modified so will keep my eye on it

so much of the info on these BL motors is confusing...... some using T some using KV some 380 and some 540

JJ

 

 

[Nitomor]

The useful thing about T on the brushless is that if its 9T (whole number) its a 380 based can, if its 9.5T (.5) for example its a 540 size based. For example I use a 9T on mine because I like the look of it, love the cooling fins and I'm not after blistering gear shredding pace!

The KV is easy peasy for working out rpm which is really what you want to know.

 

 

[Problemchild]

sweet  and wahst the difference (see my link to pdf spec sheet) between 8.5R and 9.5T

JJ 

[Backlash]

6 hours ago, Problemchild said:

I am here you know haha

JJ

Yep,,I know that you are here..

I just thought that it would be a good idea to point out that the TLBE-02s ESC is NOT rated for an 8.5T motor for those members on here who do want to listen to the advice being given in this thread.. 

Perhaps its a good thing that your not running LiPo at the moment..

[Problemchild]

ha - but its rated for the current draw .... just 

the ESC doesnt really have any hatred (or turn-ism) against the physical amount of wire within the motor

tbh the specs of ESCs shouldn't really state what they can handle in terms of turns (its only really there to guide you to motors that should be compatible as that is how they are marketed). turns are not directly correlated to current draw as wire quality and thickness can play a part on its ability to draw current

having said that, RC guidance states i should have 20% spare draw in my ESC but i will only have 10% 

JJ

[Backlash]

Yes, the motor limit on ESC's is just a guide, but it is stated by the ESC manufacturer.. The current rating of an ESC is the generally just the current rating of the FETs inside the ESC, but you don't always know if it is the Continuous or Peak current rating..

Take the Tamiya TEU101BK and the HobbyWing Quicrun 1060 ESC as an example..  Both are rated at 60 Amps..

The Tamiya TEU101BK ESC has a rated motor limit for the Sports tuned motor (23T) only.. The Specs for the TEU101BK state that it has a 60A Max continuous rating..

The Quicrun 1060 has a rated motor limit of 12 turn motors (on 2S LiPo).. The Specs for the Quicrun 1060 also state that the 60A rating is continuous (360A Peak)

Now, why is it that the manufacturer of one of these 60Amp ESC's has a motor limit rating of a Sports Tuned (23 turn) and the other has a motor limit rating of 12 turn..??

Are you going to sit there and try and tell me that both these ESC will offer equal performance, and will run the same motor because they are both rated at 60 AMPS???

Reference..
https://www.tamiyausa.com/pdf/manuals/45029ml.pdf

http://www.hobbywing.com/goods.php?id=358&filter_attr=0

[Darat76]

I believe esc motor limits is based on what the esc can operate safely for 10-15 minutes continued usage, exceeding the recommendations runs the risk of over temping faster then the cut off circuit allows. 

Also the tamiya tble-02s has a life cut-off of around 2.5 volts per cell, or 5 volts in a 2S life battery. Lipo cut-off voltage is absolute minimum of 3 volts per cell, or 6 volts in a 2S lipo, with a recommended cut-off of 3.2 to 3.3 volts per cell (6.4 to 6.6 volts for 2S) to reduce the chance of a single cell going below 3 volts. 

Life has a nominal charge of 6.6 vs niXX of 7.2 or lipo of 7.4 volts.

I suggest sticking with nimh batteries on the tamiya esc, or getting another esc with lipo low voltage cut-off. 

[Nitomor]

8 hours ago, Problemchild said:

sweet  and wahst the difference (see my link to pdf spec sheet) between 8.5R and 9.5T

JJ 

1T lol. The 8.5 states 4400kv the 9.5T is 4000kv. So you have more rpm with the 8.5T, 400 rpm per volt, you'll be running 7.4v so multiply the volts by the kv to get your rpm.