I am trying to convert my 9.6V NiCad drill to run off a 12V Li-on battery. When I connect the Li-On directly, the motor only just slightly spins and stops. The only way I can get it to work is using a Step-down Buck Converter. Initially I thought it needs 9.6V to start working, but nope works fine at 12.3V too, just not when connected directly to the battery. What am I missing? How do I get it working connected directly to the battery? Does the DC motor need a starting capacitor?
closed as off-topic by Leon Heller, RoyC, Voltage Spike, JYelton, Dmitry Grigoryev Jun 3 at 10:46
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Leon Heller, RoyC, Voltage Spike, JYelton, Dmitry Grigoryev
Do you have the C rating and the capacity of the Li-Po battery this will give you how much the current the battery is able to deliver continuously.
The buck regulator will cause the current draw to be less on the high side so if it is the over current protection that is stopping you this might be the reason.See this page for introduction
You might overcome this by limiting the inrush current by a NPC thermistor or connecting a load in series and then disconnect it when the coils in the motor has been charged.
Also remember that the motor is rated for a given current at a given voltage. If you connect it to the Li-Po at a higher voltage the current will be greater and the potential to burn out the motor is present it definitely will run faster and hotter.
The best solution would probably be to run with a buck-converter. The protective circuit would hopefully cut out the power when your battery reaches 11.1 V but some circuitry to detect and cut off the battery should be implemented as well as to not damage the battery pack.