I have a battery power source of rated 25.9 V, rated capacity is 10Ah

I want pure 24VDC and enough current for the following loads

  1. 3 motors each of the operating voltage is 24V and nominal current is 2.5A (using TI motor driver DRV8871)
  2. 6 Sensors each of them work on 12-30V and the max current consumption is 35mA
  3. Encoder which works on 5V and max current consumption is 57mA
  4. I will also use RCOM isolated DC supply which converts 24V into 5V which will power my microcontroller board CC1350 Launchpad

My main concern is how I can convert battery voltage to 24V at enough current to power these

  • \$\begingroup\$ Do you really need to worry about that extra 1.9V? \$\endgroup\$
    – Finbarr
    Nov 2, 2020 at 11:08
  • \$\begingroup\$ Yes, because 25.9 V is only rated voltage of the battery but actual capacity can be more and if the supply voltage is more than 24 V it would destroy my sensors that's why I want to regulate it to 24V \$\endgroup\$ Nov 2, 2020 at 11:15
  • \$\begingroup\$ "can be more" is not really a helpful statement of requirements \$\endgroup\$
    – Finbarr
    Nov 2, 2020 at 11:44
  • \$\begingroup\$ but for the motors, I need max 24 volt \$\endgroup\$ Nov 2, 2020 at 13:04
  • \$\begingroup\$ I didn't look up the DRV8871, but you should know that you usually can run motors at higher than normal voltage (within reason) as long as you use PWM to make sure the average voltage is as designed. This works because motors are inductive - you're basically making a buck converter for the motor, using the motor itself as the coil. \$\endgroup\$
    – user253751
    Nov 2, 2020 at 13:28

1 Answer 1


What type of battery is this? It may be the case that the battery voltage cannot be substantially higher than 25.9V. For example, 7 LiPo cells at 3.7V would be 25.9V and the voltage is limited to that value, it cannot be arbitrarily increased. If this is the case and your sensors can tolerate 30V you don't have a problem with voltage.

You can use the DC power supply for both the encoder and microcontroller.

You have enough current header to meet the demands of the various pieces of kit but will probably have an issue on motor startup when a higher initial current is required. This may make your system "brown out".

You need to look into the startup current spec for your motors.

  • 2
    \$\begingroup\$ LiPos are fully charged at 4.2V, so it would not be limited at 25.9V, but rather 29.4V which is 7 times 4.2V \$\endgroup\$
    – user253751
    Nov 2, 2020 at 13:27

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