@tony: This should not be too much of an issue in most cases. You may wish to add a capacitor over Vin/Gnd to prevent possible brownouts. The recommended/optimal minimum voltage input for Arduino boards is 7 V DC but the minimum is 6 V DC so you should be fine.
@Mike: Unfortunately, probably not. At 900 mAh for the motor (with no load), the battery would last at most a bit less than 2.5 hours. Of course, when you add a load, the motor will use more current. Plus, its nominal voltage is 12 V DC, not 11.1 V DC, so it may use a bit more current than normal. The actual current required for the motor will vary with the load, but it should be roughly at 25-35% of the stall torque (rule of thumb/approximation). We recommend that you test your motor (loaded) with a multimeter in series to measure the average current required. For our example, we will assume a continuous current of 1775 mA. If this was to run for 6 hours, you would need a minimum battery capacity of about 10650 mAh (= 6 h x 1775 mA). One possible option would be to combine two RB-Sta-11 in series to provide enough voltage, current and capacity.
@SĂ©bastien: Hm, I thought the discharge current of the LiPo plays a role here from what Iâve read (but probably misunderstood) above between the conversation of @Coleman & @daan.
From what I understood, if my total stall current say = 7A; and my LiPo has a âCâ rating of 30C, so I get 7/30 = 0.23A. Thus if i want to run it for atleast 6 hours, itâs 0.23*6 = 1380mAh.
I would now require a minimum of 1380mAH of that LiPo battery (of 30C).
So, this is a calculation mistake then? Thank you for reply by the way.
Good afternoon, thank you for the excellent information youâve posted on this awesome site. I am currently building a prototype cooling unit using 2 CPU 20mm fans. (DC 5V 0.5W). Can I use a standard 9V battery? What would you recommend? Thanks again.
@Mike A LiPo battery may have the following specs: 11.1V (3S), 5Ah, 25C discharge. The 3S represents 3x 3.7V = 11.1V, the 5Ah = 5000mAh represents the capacity, and the 25C represents the maximum discharge rate, which would be 25 x 5 = 125A. If your motor consumes an average of 7A, this battery would last 5/7=0.714 hours (assuming 100% efficiency).
@jack It depends on the motorâs voltage range / tolerance. Why not use a wall adapter instead (a battery wonât last very long).
can i use AC adptor 8v 0.5A to charge my 3.6V 2000mah ni cad battery? sorry im a newbieâŠ
@erwin If youâre new to electronics, itâs really best to use an actual charger to charger batteries (a lot can go wrong and be dangerous - itâs not worth saving a few dollars by trying to create your own charger).
respected sir,we are trying to run stepper motor having operating voltage between 12-24 V and current capacity 2.8 A ,with motor driver circuit having maximum current bearing capacity of 5 amp and 2-5 volt.we earlier tried to run it with battery having capacity of 12 V & 5Ah and motor driver circuit is getting over heated.which battery we can used in this case which can continuously run the motor for 2 hours ??? Is that any problem with motor driver?
@jp If the motor controller is getting hot, that means it cannot provide the necessary current for the time you need, and you might want to find a different controller. The batteryâs discharge current only affects how much current is available to the controller; from what you described, the battery can provide the necessary current.
sir, I am building a hexapod robot with 18 servo .i am using 7.4v 1500mah 20c Lipo battery. but i need a 6v to all 18 motors .how can i get
6v without reduction in current.
@VENKAT It would be best to have either chosen servos which can accept 7.4V input, or choose a 6V battery pack. You can use a voltage regulator which can handle enough current to drop 7.4V to 6V: https://www.robotshop.com/en/power-regulators.html
i need to use 4, 12v high torque motors which can draw upto 8a current each while starting, and i am planning to use one 12v 10ah battery for all four, is it a good idea??
@supreeth It depends on the chemistry and max discharge rate. If all four motors operate, the total current draw would be 32A, so the battery would need to be able to discharge at a minimum of 3.2C (likely 4C, and 5C is better).
Hi, thanks for the interesting website. Iâm new to this and creating an off road vehicle controlled from a Raspberry Pi. I have 4 x 12V DC motors rated as 100RPM, 0.61Kg-cm and 0.23A. Can you recommend the spec of battery best to use? I assume Lipo 11.1V is better than NIMH 12V
@Justin If the current draw is 0.23A, and there are four motors, then a quick estimate would be that all of the motors can consume 1A. The battery capacity will determine how long the robot lasts, but the higher the capacity, the heavier the battery. LiPo is normally lighter than NiMh and can discharge at a higher current. They are more difficult to use, and chargers tend to be more expensive.
Hey bro,
I am making a robot and I am using an arduino mega as the controller.
I am using 4 DC Motors, 02 servos and a stepper along with a couple of sensors. There are limitations on the weight of the device.
Can you suggest me the best battery to power my device with ?
Cheers
@Arsalan If itâs a mobile robot, you should choose a battery pack whose voltage corresponds to the nominal voltage of the motors; ideally this will be above 7V so you donât need a second battery pack. The capacity affects the time of operation as well as the maximum discharge current.
Ok here is a question I have an Ironman suit lights, speaker, and helmet motor that movies faceplate up and down. At first I was running 3.7 volt batteries in a pack of 4 to run it. Would it be better if I ran it off of a 9.6 battery pack because of how long it takes to charge the 3.7 volt batteries and I have multiple 9.6 battery packs? Weird question but would love some advice please.
@Matthew It depends on the voltage of the main actuator. Can you create a new post on the RobotShop Forum with details of the components (a photo or two would be nice) and re-state your question?