Input power


I will need to power my recently ordered SVP with a car battery attached to charger/alternator which can output 14.7V. The spec for the board is 6 - 13.5V. Is there something simple that can be done to reduce the input voltage from the charger or can the board handle higher voltages? Any suggestions are greatly appreciated!


The motor drivers on the SVP have an absolute maximum voltage of 15 V, so 14.7 is getting very dangerously close to the limit of what they can tolerate. This is not something I would recommend. Do you have the option of disconnecting the charger from your battery when you run the SVP? If not, you might need to use a different power source for the SVP, such as a separate battery, or you can place a high-current regulator between your car battery and the SVP. Do you know how much current you will need for your SVP (i.e. what motors, servos, and sensors will you have connected)?

- Ben

Thanks for the feedback Ben. I will be using the SVP on two projects, one will be the SVP + ~400 ma for a motor and the other will be the SVP with a 4 line LCD and just an encoder board. I will need to create a regulator for them, better in the long run.

- kalk

Is that motor current the free-run current? If so, note that the motor might draw many times that current at stall, so you should pick a regulator that can tolerate such current spikes, or you should take steps to ensure that your motor does not stall. Additionally, if you give your motor full power from rest, it will briefly draw nearly the full stall current, and if you go directly from full speed forward to full speed reverse, it will briefly draw nearly twice the stall current. You can limit such acceleration-related current spikes by limiting motor acceleration in your code (e.g. gradually ramp up your speed over time rather than just setting the new speed immediately).

- Ben

Great observation, the free run is 400 ma with a stall of 2.0 A (big difference). I’m coming to find out the motor is subjected to stalling. The good news is the reversing is not a requirement. Ramp table devlopment is in my future (lol), I’ll watch for harmonics. Thanks again for the great feedback.