What shul I buy?

[rehnskit]

Hi, what should I buy?

I been thinking to buy this for my project. Please comment if it's okay or not.

This project contains Sbrick...

I want to buy this:

3 sbrick, each powered by LiPo batteries 3S 11.1v 2600mAh.

Two of the sbricks are used for two custom motors. I been looking att the normal rc motors with about maximum 15 volts.

The last sbrick is used for 3 or 4 Lego servo motors and maybe 1 or 2 smaller Lego motors.

Will this work?

Edited February 12, 2016 by rehnskit

[DrJB]

We need more information about the project, the motorized functions ... etc. Each SBrick can run several motors. WHy do you need 3x of them?

[nastystage]

Hi all, this is my first post. I starded with lego technic when I was a child with 948 go kart....and after many years I came back from my dark age with the Unimog ...and read this forum every day

I also play with rc cars and planes and I'm pretty sure you cannot use a 3s lipo battery on sbrick because the "Absolute maximum voltage" is 11.8V and a full 3S lipo delivers 12.6 Volt.

You can use a 2S with lego motors, but not with standard rc motors because the ampere request will blow the sbrick.

https://social.sbric...uide-for-sbrick

Edited February 11, 2016 by nastystage

[rehnskit]

If I run the 2 big motors at about 10 volts I need 2 sbrick.

Why I need this much motor power is becouse I got 16 big wheels. The project is far from finished but I think it's weight will be at least 4 kg only in Lego parts. And then add all motors and batteries. And still want some speed and strength.

The 3rd sbrick is for everything else.

Something else you want to know about the project?

After I been reading about 3S and 2S LiPo's for Lego projects with sbrick. It sounds like it's ok with 3S. And if it's to much I can use a diode or something else to remove 1v. I think it's stupid to choose 7.4v instead of 10-11v.

But I think I will use 2S for the 3rd battery.

Of course I can use a normal rc motor with a LiPo S2 battery. There is the same kind of motor in Lego motors but less powerful. I think they are called brushed electric motors. And they are cheep much less then €10.

But what I not found a real good answer for is how much amps I can choose for the battery (mAh)? I've seen pictures of people use 2600mAh. But then some people say that the maximum for Lego and sbrick is between 1000 and 1500 mah.

And I found a good price for a 3S battery with 3500mAh. But I don't know if that's possible.

And the other thing I wounder about is if I will be able to gear down all this power from the 2 motors with lego parts?

And after that connect it to a gearbox. Or if it's possible to connect directly to a gearbox before I divide the power to all 16 wheels?

Both motors will be joined on the same axle before the gearbox...

Maybe I will have to use a real rc gearbox to gear down everything first. Before I start to use lego parts.

Edited February 12, 2016 by rehnskit

[rehnskit]

This what I'm talking about...

Motor:

http://www.conrad.com/ce/en/product/244449/Motraxx-X-Drive-540-2-Multipurpose-Electric-Motor?promotionarea=01

Batteries:

http://www.conrad.com/ce/en/product/239039/Conrad-energy-LiPo-Rechargeable-battery-111-V-XH?ref=list

http://www.conrad.com/ce/en/product/239037/Conrad-energy-LiPo-Rechargeable-battery-74-V-XH?ref=list

Sbrick:

https://social.sbrick.com/store/product/9/sbrick

Edited February 12, 2016 by rehnskit

[nastystage]

For the batteries: Your only matter should be the voltage. If you stay below 11.8 you can use a 10000mah or higher if you want. This will not hurt the sbrick.

For the motors: You have to choose a motor with ampere consumption that not exceed sbrick limit.

ps. sorry for my english

Edited February 12, 2016 by nastystage

[rehnskit]

Thanks that was what I was hoping for.

Then I will buy the 3500mAh.

Ok. So I have to choose a motor with correct Amps. I'm going to find out the sbricks maximum. And then find the best motor.

But what would happend if I choose a motor with to much Amps? Will the sbrick break?

[nastystage]

But what would happend if I choose a motor with to much Amps? Will the sbrick break?

yes, it will overheat and break

[rehnskit]

Ok

The sbricks maximum per channel is 3A. If the temperature is not too high.

So then I could choose this motor with 1.6A and almost 15000rpm.

http://www.conrad.com/ce/en/product/244520/Igarashi-2738-051-GC-5-Multipurpose-Electric-Motor?ref=list

But I think there is a better motor for me. I will continue my search.

I just wonder how I could figure out the temperature. If it could be a problem for me?

And what exactly what is going to be hot? The sbrick, motors or the Batteries? Or everything?

Becouse there is ways to cool motors.

[nastystage]

I just wonder how I could figure out the temperature. If it could be a problem for me?

And what exactly what is going to be hot? The sbrick, motors or the Batteries? Or everything?

Becouse there is ways to cool motors.

Sbrick and maybe wires.

The battery will heat only if it has not enough ampere discharge to feed the motor....but with a 3500mah and 30c dicharge you will not have this problem (3,5x30= almost 100A!!) (with this kind of battery you can power a fast rc professional car or a multicopter like dji phantom without problems )

Edited February 12, 2016 by nastystage

[rehnskit]

Ok

And what do you think about this if I choose a motor with 2.8A and 11v?

Is the sbrick going to be to warm?

No one in this forum that done something similar?

Edited February 12, 2016 by rehnskit

[SevenStuds]

Straight from the guys at SBrick:

"If you really want more power, consider using RC car/plane batteries. I used a 2S 7.4V LiCoO2 1500 mAh battery for my early SBrick stress tests, costs 1/4 of a LEGO LiPo and lasts 2x more (but you also need a charger). It has 25C capacity so in theory you can get 37.5 A (play safe, please)."

You can read more here to find out about the amp limits per SBrick port: https://social.sbrick.com/forums/topic/103/sbrick-and-5292-rc-motor

As a thought, if you're using 3rd party motors and batteries, why not just go all the way and just use a full hobby/RC setup with remote and receiver? (Since clearly purism is not something you're after.)

[rehnskit]

Ok. I guess I go with the safe way and buy 2S LiPo's. And motors under 2 amps.

Now I only want to know if it's possible to build a gearbox that will hold for this power.

No I don't want to use normal rc equipment. Only when I have too... Because Lego doesn't offer me anything I'm happy with. I love Lego. And if they would go for more power in the future I would love them more.

I'm a Lego builder and I want as much as possible to be Lego. And I love the sbrick. The sbrick is the reason why I wanted to build something big and powerful.

[aminnich]

Im just curious, If you are using 3rd party motors, why dont you just use a third party receiver instead of the sbrick?

I am also into RC cars and I have actually thought about doing this, but all of my motors are too powerful for the plastic gears

[rehnskit]

Becouse I'm a Lego builder. I don't know anything about the rc world.

But yes maybe in the future I will start doing that. Especially if Lego don't come back with something like the buggy rc motor.

[DivenParker]

You should buy a 4s lipo battery because the normal rc motors with about maximum 15 volts. You must sure your motors work well.

[JJ2]

Selfless advertising here but I have used non lego motors with an Sbrick and it was a bad result, the slight delay in Sbrick is not noticeable while driving slower creations but that delay could mean either you creation in the ditch in 1000 pieces or still on the road, I would recommend using a RC receiver not sbricks.

Here is a good cheap remote with a receiver that I use to control my models

https://www.amazon.com/FlySky-FS-GT3B-2-4GHz-3-Channel-Transmitter/dp/B00FS2UAHS/ref=sr_1_1?ie=UTF8&qid=1476459902&sr=8-1&keywords=flysky+receiver+remote

and here is a good ESC to control you motor

https://www.amazon.com/HobbyWing-QUICRUN-1060-Brushed-ESC/dp/B00LXCM3Q8/ref=sr_1_6?ie=UTF8&qid=1476460067&sr=8-6&keywords=RC+car+esc

Those are the best cheap ones but here a Traxxas ESC that is made for Lipo batteries.

https://www.amazon.com/Traxxas-Electronic-Waterproof-low-voltage-detection/dp/B0046LBJCM/ref=sr_1_16?ie=UTF8&qid=1476460120&sr=8-16&keywords=RC+esc

I would also recommend buying a Traxxas 550 12T motor, it is a great high quality motor as long as you cover it up making sure no particles can get into it

https://www.amazon.com/Traxxas-3785-Titan-Turn-Motor/dp/B000HKH0T2/ref=sr_1_1?ie=UTF8&qid=1476460257&sr=8-1&keywords=Traxxas+550+motor+12T