[SOLVED] Can AAA battery power a 5V stepper motor?

[bobsun]

Hi,

Can a stepper motor be driven by batteries?

Parameter:
Nominal voltage: 5V
Current: 700mA

For standard AAA batteries, the voltage is 1.5 each, so putting three or four in series would provide enough current. However, I wonder if AAA battery could deliver 700mA of current? 700mA is close to 1A, and is in fact quite large from many perspectives. Is there any example that stepper motors of this class is driven by consumer batteries?

I had some difficulties in getting the maximum rating of current for batteries. For example, many batteries are marked with only the capacity like 700mAh for an AAA battery. The nominal voltage of AAA battery is 1.5V, but how could I know this 700mAh rating is for either

1. 700mA over 1 hour
2. 70mA over 10 hour

?

https://en.wikipedia.org/wiki/Battery_(electricity)#Battery_capacity_and_discharging seems to suggest that the convention is actually a 20× multiplication:

The battery capacity that battery manufacturers print on a battery is usually the product of 20 hours multiplied by the maximum constant current that a new battery can supply for 20 hours at 68 F° (20 C°), down to a predetermined terminal voltage per cell. A battery rated at 100 A·h will deliver 5 A over a 20 hour period at room temperature. However, if it is instead discharged at 50 A, it will have a lower apparent capacity.[45]

So does it mean a 700mAh battery could only supply a constant current of 35mA? It seems pretty frustrating since if this is true then there is no way such a battery can drive the stepper motor above.

Hope someone could help.


Bob

 

[tpetar]

Hi my friend, situation is very simple.

You cant use something that is not exist, there is not enough energy in AAA battery.

We can put four AAA batteries in serie to achieve 6V with one diode we can lower that voltage to 5,3V.
(also consider voltage drop while load is present).

But for capacity mAh, we must put batteries in parallel connections to achieve needed capacity.

All of this with AAA is under question, because You need high number of this batteries.

What is time needed for runing that stepper?

This is job for lithium batteries or lead acid (gell/glass) sealed!!!

 

[bobsun]

tpetar,

The time needed is extremely short. It's micro-control situation in that during each minute the motor rotates about only 5 seconds.

You suggested putting AAA in parallel, but may I know what is the maximum supply current of a single AAA cell, and also a AAA cell?


Bob

 

[tpetar]

Bob,

When batteries go to serial then voltage is added, and when is parallel connection then voltage is the same but capacity is added.

For Alkaline-manganese:
AA capacity is 2000mAh with typical drain of 50mA.
AAA capacity is 1000mAh with typical drain of 10mA.


When paralleling batteries there is problem of inequality of battery properties (internal resistance/voltage). Battery with lower voltage will discharge battery with higher voltager.

When batterie is in serie (chain of batteries) there is also problem of battery properties (internal resistance/voltage) each link in the chain must give current, if one is poor or bad than all circuit current will be on question.

 

[bobsun]

tpetar,

In the above post:
Drain = current?


Bob

 

[tpetar]

Yes

Drain = consuption of current





You can add lots of this batteries even to start car, but money time, purpose of this,....... :wink:



For this my suggestion is to use rechargable batteries (consider charger for this) :

LeadAcid Gell/Glass sealed battery


or


Lithium

 

[bobsun]

tpetar,

I will study the options. Thanks for suggestion.

Bob

 

[tpetar]

Look this video for relaxing :

Starting a Car with a Toy Plane Battery - YouTube

 

[bobsun]

tpetar,

My company blocks Youtube so I simply cannot watch it. Thanks all the same.

Bob