@ahasan It could be that the servos cannot handle the torque - they might not be powerful enough for your application. We don’t have any experience with Turnigy to know comment on their quality or reliability.
I need to charge bluetooth module: 3.3 v, microcontroller: 5v and gyroscope:3.3. Total current is 2.6Mah. WHat will be the best way?
@S You mean power them all or charge a battery? Some microcontrollers have a 3.3V output pin, so 5V to power the microcontroller and 3.3V to power the sensor and BT module perhaps?
I live off-grid and I have a voltmeter that indicates the charge of my battery bank. It operates off a 9v alkaline battery. Could the 9v alkaline be substituted with a 9.6v 2.2ah battery? My current understanding is that a device will draw only the current it needs so if the voltage is close enough the higher amperage shouldn’t bother?
@Geoffrey Wight Correct. If your device is 9.6V tolerant, then higher capacity simply means it will last longer. The one exception, which is likely not the case here, is when the higher capacity battery cannot discharge at the required current (normally affected by battery chemistry).
I have two 6v dc motors connected to L298N Driver… Should I use 12 volts battery? Sorry for my stupid question.
Dear Mr Benson,
Thank you for this very well-written post/tutorial. I am currently working on a hand prosthetic and am developing a wearable wristband to read emg signals. The wristband contains the following:
- Arduino Pro mini 5V ( Typical supply voltage: +5.0 V, Typical supply current: 10-25 mA)
- Transmitter Module ( Typical supply voltage: +5.0 V, Typical supply current: 03-10 mA)
- Myoware muscle sensor ( Typical supply voltage: +5.0 V, Typical supply current: 09-14 mA)
I am currently looking for a battery to power these components. The battery needs to be as small and as light as possible. It also needs to be rechargeable. There is no minimum operation time due to the project being a prototype, however, the longer the duration the better. I am currently looking at the s 200mAh 2S 7.4v 20C LiPo Battery
( http://www.overlander.co.uk/batteries/lipo-batteries/eflite-umx-beast-type-lipo-battery.html )
and wanting to connect it to 5V Step-Up/Step-Down Voltage Regulator S7V7F5 to connect the battery directly to the VCC pin bypassing the Arduino low efficiency regulator.
( http://www.hobbytronics.co.uk/s7v7f5-5v-regulator?keyword=5v%20step-down&category_id=0 )
Now I understand I need a protection circuit board/module to protect the Lipo battery. Can you please advise me on these protection boards. Also please tell me if you think that another battery type will better suit my needs.
A large update on my questions which I also posted on the forum:
I am currently looking at a 240mAh 1S 3.7v 25C LiPo Battery with a 5V Step-Up/Step-Down Voltage Regulator
http://www.overlander.co.uk/lipo-batteries-240mah-1s-3-7v-25c-sport-hubsan-x4-mini-quadcopter-type.html
https://www.coolcomponents.co.uk/5v-step-up-step-down-voltage-regulator-s7v8f5.html
Question 1) Will the battery and voltage regulator combined work fine with the components mentioned above?
Question 2) Would I need a PCB for the LiPo?
Question 3) Is there another battery type or battery spec that better fits my needs?
@Mohamed Happy to help. Since your issue is more design related, can you create a new topic on the RobotShop Forum and copy/paste what you wrote here? https://www.robotshop.com/forum/power-systems-f79
Hi, so I have a 12V DC motor, 4.9W with a max load I = 410 mA.
I don’t need it’s full power, so I wanted to use an accupack of 7.2V (6 cels) to power it. The motor has to work for only 20 minutes (= 123mAh). Would this be possible and if so, do you have an idea wich accupack I should use? thanks!
@daan If the stall current is 0.41A, you can assume the continuous current is around 0.12A, so if you want it to last 20 minutes, you’d need a 12V, ~40mAh battery. You might consider an 11.1V, 50mAh to 100mAh LiPo pack: https://www.robotshop.com/en/power-systems.html
I’m currently working on a Robot with 2 dc motors (6v nominal, and 1.08A) with 4 to 6 servos, I want to use 11.1V lipo packs, which packs should i choose? ( C rating and the mAh) help
@med If you are using RC servos which operate at 4.8V to 6V nominal, an 11.1V LiPo will kill them, so you either need a separate battery or a voltage regulator. The C rating is the capacity and the discharge rating is normally provided as a multiple of the ‘C’ rating. The capacity relates to how long the robot will last. For example if your 11.1V battery has a capacity of 2000mAh (2Ah) and can discharge at 5C, that means it can discharge at 10A, which is more than enough for your motors.
I am making a robot with 9 mg995 servo motors, I tried to google how much volt each requires but I didn’t find an answer, my question is what battery should I get, I read horror stories about batteries blowing up, I don’t want that happening, I heard nimh batteries are the safest but still tend to explode, please let me know what battery I should get to run 9 mg995 servo motors for my robot
@marcus jones: According to datasheets we found online, the TowerPro MG995 servomotor uses a voltage range of 4.8-6.0 V DC (normal RC servomotor range). Your best bet would be to use NiMH 6.0 V DC battery packs, such as this one. Depending on how many servomotors you will use / how long you want it to last, you may want a larger capacity batter pack. You can search for other 6 V DC NiMH battery packs here. You may also want a servomotor controller board (if using with a computer or a microcontroller), such as the SSC-32U. Concerning battery fires/explosions, this should never happen if you battery can provide enough current for the use you make of it. Batteries usually only overheat (and possibly get damaged) when they are forced to provide too much current quickly or when they are over-charged. Of course, never charged a battery pack without supervision. You should be using a smart charger, such as this one.
thnx! this really helps, one question though: I’m planning to use a 6 V 3700 mAh NiMH battery pack, to power my robot. it will have two 6v DC motors and two 6V servomotors. But is also need 9V + to power the microcontroller. a step up converter might be an option, but is it as simple as just putting a step up converter between the microcontroller and the batterypack, and combining the grounds from the motors to the battery whit the grounds back to the microcontroller?
@tony: Which microcontroller are you using? In most of our Lynxmotion kits, we use a 6 V DC battery pack directly with our microcontroller board without issues. You may want to add a capacitor to prevent brownouts. Most on-board voltage regulator can handle about 1 V of difference between input and output at low current drains (such as with a microcontroller chip). If your board really needs 9 V DC or more, than you can use a step-up converter (such as this one) and link up the grounds together.
Hi, I currently have 2 12V DC Geared Motors with specs:
- Free run current : 900mA
- Stall Current, 12V: 3400mA
I want my system to operate for atleast 6 hours, and I have an 11.1V LiPo 2200mAH 30C. Will this achieve the operating time? If not what what should I do to achieve this?
Thnx, I will use a arduino mega 2560 board.