andrei66

The lipo is connected directly to the driver, and in the same terminals I routed 2 wires that connect to a regulator that provides 10V for the hub. The ground is common there. These were previously connected to the lipo balance and gave power to all motors when there was no external driver. And Happy New Year to all of you!

Hi again, I managed to make everything work with the L298N driver. The PWM signals of the MCU are given straight to the driver via jumper pins, the motor wires were spliced and screwed into the OUT terminals, while power comes from a 4S LiPo 1300mah wired directly to the driver. The speed and power difference from previous 10V is significant. I am very pleased with the result. All in all, I can say the 2 to 3V of voltage drop is benefcicial in this case, since there is less of a chance of burning the motors. Here are some pictures: https://imgur.com/a/yihaVEC After running it for a while, the motors barely get warm, only the driver's radiator heats up. Haven't had any issues except for the occasional clicking gears, but I think that is to be expected since the power output is increased. Thank you all for your suggestions and ideas!

1. I did not know this was an "ancient" driver, I only worked with BLDC drivers before, and a Sabertooth 2X60 for DC motors, which is way too overpowered for these motors. Could you recommed a modern DC motor driver that would be good for this task? 2. I saw they were quite thin, I was also worried about this, maybe changing the wire too would be a good option 3. This was actually my main concern, at first I wanted to completely replace the motors (I also have a 3D printer), but I figured it was to much fiddling around, and so I thought about boosting the current motors. By the way, do you know what kind of DC motor size would fit in place of an Control+ XL motor? I know the interior motor is quite small, but I'm not versed in DC motor sizes. 4. Ah yes, I didn't realize the output of the driver is also PWM, but instead of 0 - 3.3V it is driven at 0 - Battery voltage. Good point there, I missed this observation. Yes, practically a voltage divider that divided this voltage by about 3 would be the same deal when it comes to the input signal for the new motor driver. Thanks for the advice. I'm having doubts now whether this would be beneficial in the long run. Certanly a good thing I wrote here, maybe I would have done it and toasted the motors soon after. I think I'm going to think better about this mod, maybe explore some other motor options and check out other drivers. Thank you! Yes, it does. And the datasheet for the original driver says min high is 1.8V, so I would bet that the actualvalue is 3.3V from the MCU, since that is what it delivers on its output pins, although I could be wrong. I will measure it too to be sure. But @biasedlogic suggested a better idea of using the motor output directly, with a voltage divider (that would map the 0 - batt voltage values to 0 - 3V for example), so I think this is a better idea

Hi, I have been a LEGO fan as a child, and I recently received a Lego Technic set (42099, the 4x4 offroader). As an engineer myself (now, at almost 22), I began modifying the truck to make it faster and more powerful. I have already added a 4S LiPo pack using a regulator to 10V output, inside a box I found on @Philo's website (for the Control+ hub). The performance is now a lot better, and it does not decrease with battery discharging (since the output is a fixed 10V from the regulator). However, I am now thinking about changing the motor drivers, by bypassing them. I am only taking about the 2 driving motors, the steering motor will be left as it is. I studied the datasheet of the LB1836 driver and found that the IN1..4 signals that drive the 2 motors must be PWM (since there are no other pwm control inputs), and they should be 3.3V (since the STM32 is providing them). I bought an L298N dual driver module after studying its datasheet, and found that it has an almost exact input structure: 2 IN signals (which can be PWM) per motor, and an extra EN signal (enable, usually used with arduino projects for pwm speed control, while the IN signals are either 01 or 10 for direction), but from the arrangement of the logic gates and the statement that the IN signals are "TTL compatible", it must mean that you can directly use PWM on the IN signals, while setting the EN signal to 1 (using a provided jumper), so in theory, I could break the M1 and M2 lines from the C+ hub, cand power the motors from this driver instead, using the same input signal as the existing driver, by soldering wires to the PCB and routing them to the inputs of the motor driver. This would mean powering the motors from about 15V (full charge) to about 11V (considering the ~2V voltage drop of the driver) My question is, since I have seen this is a very active and engaged community, whether anyone has ever done this kind of thing before or is even thinkinh about it. My quest for power comes from the fact that I previously had a modified RC car that I fitted with a 3000W electric motor that hit 120kmh and had immense power. I know I am never going to reach that with this offroader, but I will at least try to get the most out of those motors. And yes, I know about the resettable fuse in the motor case and its current limit, and I do not think it will be such an issue. Thank you kindly for your help! Any ideas are appreciated. You can see for yourself the datasheets that I referenced: https://www.sparkfun.com/datasheets/Robotics/L298_H_Bridge.pdf (new driver) https://www.onsemi.com/pub/Collateral/ANDLB1836M-D.PDF (original driver) https://www.flickr.com/photos/147573503@N04/albums/72157711852953692/with/49092205906/ (PCB with traces, where I would take the signal from the driver contacts, according to the datasheet)