0
\$\begingroup\$

For a home pet project I want to wire up an electro motor to a Raspberry Pi. I want to constantly reverse the direction of the motor (meaning I want to be able to change the direction of the motor about every second). As far as I understand this can only be done with brushed DC electro motors. Since I need quite some power, I was thinking of buying

1. Motor

this electro motor, which is described as:

200W DC motor is reversing 24V speed control motor 1800 rpm high torque micro motor

enter image description here

2. Battery pack

I then want to wire it up to this LiPO battery pack, which has the following description:

Output voltage:12V-24V
Input voltage: 12.6V
Input current: 1AH-2AH
Output current: Max. 6AH
Output power: Max. 110WH
Material: Li-polymer for PHILIPS 2900MAH batteries 
Capacity: 52000MAH(3.7V)

[EDIT]

@MarceloEspinozaVargas told me in his answer that the battery pack has a regulator which is too weak. So how about I buy two of these battery packs (2*12V), serially linking them up so that I get 24V, and then using this regulator, which says it is a DC-DC Automatic Boost Buck Converter 8V-30V to 2V-16V 6A 80W CC/CV Voltage Regulator charging 5v 12v 24v 19v Car power supply. Would that work you think?

3. H-Bridge

I then want to use this H-bridge for reversing the motor direction, which comes with the following info (description below picture):

enter image description here

Double BTS7960 43A H-bridge High-power Motor Driver module:
BTS7960B H-bridge 43A high-power motor driver Module Overview:
This driver uses chips BTS7960 composed of high-power drive full H-bridge driver module 
with thermal over-current protection. Double BTS7960 H-bridge driver circuit, with a 
strong drive and braking, effectively isolating the microcontroller and motor driver! 
High-current 43A

Features:
Double BTS7960 large current (43 A) H bridge driver;
5V isolate with MCU, and effectively protect MCU;
5V power indicator on board;
voltage indication of motor driver output end;
can solder heat sink;
Just need four lines from MCU to driver module (GND. 5V. PWM1. PWM2);
isolation chip 5 V power supply (can share with MCU 5 V);
size: 4 * 5 * 1.2 cm;
Able to reverse the motor forward, two PWM input frequency up to 25kHZ;
two heat flow passing through an error signal output;
isolated chip 5V power supply (can be shared with the MCU 5V), can also use the on-board 5V supply;
the supply voltage 5.5V to 27V;

My Question

Before spending the money on it, I want to be sure that this combination will actually work. I mean; does that seem like a good battery pack for that motor, and can the H-bridge I link to handle the power going through? I see the H-Bridge says

I'm just a bit insecure about spending all this money when it's not going to work. So all tips are welcome!

\$\endgroup\$
  • \$\begingroup\$ I don't speak Spanish very well so the link is fairly useless to me but I would urge you to NOT buy anything that doesn't have a recognizable data sheet and a recognizable supplier. As for "constantly reverse the direction of the motor" you need to define this in a much more clear cut way. \$\endgroup\$ – Andy aka Feb 10 '17 at 10:51
  • \$\begingroup\$ @Andyaka - Which website opens in Spanish for you? All of them open in English for me. About the constantly reverse the direction of the motor; I mean that I want to be able to change the direction of the motor about every one or two seconds to balance something. \$\endgroup\$ – kramer65 Feb 10 '17 at 11:07
  • \$\begingroup\$ Motor: 200 W motor de la CC es de marcha atrás 24 V de control de velocidad del motor 1800 rpm high torque micro motor \$\endgroup\$ – Andy aka Feb 10 '17 at 11:24
  • \$\begingroup\$ Data sheets are needed, not buying pages. \$\endgroup\$ – Andy aka Feb 10 '17 at 11:24
2
\$\begingroup\$

Based on your last edit, your battery pack is not a 12V battery, it's an array of 18 3.7V cells that give you 54000mAh with 3.7V output, the regulator it has is actually a step up regulator, so it converts your 3.7V in a 12-24Vdc, what you would need us a step up regulator that can boost 3.7V into 24V with at least 20A

\$\endgroup\$
  • \$\begingroup\$ Alright thank you very much. I just added a different suggestion for a regulator under Edit under point 2. Do you think that would work? And do you think the H-bridge is ok? \$\endgroup\$ – kramer65 Feb 10 '17 at 14:10
  • \$\begingroup\$ The H Bridge seems OK, but I don't think it could handle that much power (24V*20A aprox 480W) without a cooling fan at least. \$\endgroup\$ – Marcelo Espinoza Vargas Feb 10 '17 at 14:14
  • \$\begingroup\$ For the new battery pack, it's a 12V 4.8Ah LiIon pack, so the max amount of current you could get from them is 4.8A, since it doesn't tell the maximum discharge capability we asume a 1C of discharge. You might look for battery packs for RC that are capable of release 20C to even 100C of discharge ratio \$\endgroup\$ – Marcelo Espinoza Vargas Feb 10 '17 at 14:16
  • \$\begingroup\$ Alright thank you. I'll look for one. And do you think the H-bridge is ok for the motor? \$\endgroup\$ – kramer65 Feb 10 '17 at 14:17
  • \$\begingroup\$ It looks OK, I'll check the datasheet of the BTS7960 (you should take a look too robotpower.com/downloads/BTS7960_v1.1_2004-12-07.pdf) and come with a better answer \$\endgroup\$ – Marcelo Espinoza Vargas Feb 10 '17 at 14:28
1
\$\begingroup\$

Based on the products description, the motor can easily draw more than 13A when using with load, that exceeds a lot the maximum current of your regulator (6A), besides the motor description doesn't show the stall torque and current, and it might be a lot more than 13A, so that regulator is not going to drive the motor unless the motor carries an extremely low load (in which case you'd better go for a smaller motor)

\$\endgroup\$
  • \$\begingroup\$ Thank you for your answer. So how about I use a different battery pack with a different regulator which can handle a higher Amperage. I added a description above in my question under point 2. Do you think that would work? \$\endgroup\$ – kramer65 Feb 10 '17 at 14:09
  • \$\begingroup\$ You're always welcome. I posted another answer to this question, check it. \$\endgroup\$ – Marcelo Espinoza Vargas Feb 10 '17 at 14:10
0
\$\begingroup\$

Since you are actually going to buy something, buy a professional servi drive with a servo motor. It will be so much more fun! If you need something cheap, take qs9 from here:http://www.adtechen.com/news/QS9-Series-High-performance-Servo-Drives.html. i think it's best calue for money- chinese servo with world level performance.

\$\endgroup\$
  • \$\begingroup\$ Thank you for your suggestion. Any idea where I can buy those online? \$\endgroup\$ – kramer65 Feb 10 '17 at 14:17
  • \$\begingroup\$ This specific device- probably only from Adtech website. But there are more. \$\endgroup\$ – Gregory Kornblum Feb 10 '17 at 17:38
  • \$\begingroup\$ But a servo motor is going slow, but with a lot of torque right? I need at least 1000rpm, so I don't think a servo motor is good for me. Or am I wrong and can a servo motor actually do a high rpm as well? I'm all up for buying something professional, but I have no clue which ones are professional, so any more tips or links are welcome! \$\endgroup\$ – kramer65 Feb 11 '17 at 9:30
  • \$\begingroup\$ Not sure about servo at tour place, thus specific worked well on 10000rpm in my lab. \$\endgroup\$ – Gregory Kornblum Feb 11 '17 at 9:31
  • \$\begingroup\$ You probably refer to stepper, it's something different \$\endgroup\$ – Gregory Kornblum Feb 11 '17 at 9:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.