Which Battery & How to charge the battery via solar?

Other Hardware Motors, Mechanics, Power and CNC
1

Hi There,

First up I am new to the Arduino world, so hopefully my questions are valid.

I am doing a project where I need to power the following components and need to charge a battery via a solar panel.

I need to power the following -

  1. Arduino Uno (5V)
  2. Dual H Bridge Stepper motor drive (5V )
  3. 45rpm 15.5mm Gear Motor (12 V)

Question 1 - Would a 12V battery be able to power the above ? If not what battery configuration should be used.?

Question 2 - How can I charge the battery via a solar panel?

The Gear Motor and the Dual H Bridge Stepper motor will be used very little about 3 minutes twice a day so the battery charge will be minimal I presume.

Hopeful this all make sense.

Thanks in advance

Tony

2

Stepper motors and solar panels do not go well together because stepper motors are very inefficient. And if you de-power them to save energy you can easily lose position.

It would help if you describe how your project is intended to work.

A 12v battery should be fine - lead-acid batteries can take a lot of abuse without catching fire. But they do need to get a complete charge at about weekly intervals.

The required capacity of the battery in Amp-hrs depends on how much energy you need, the size of your solar cell and the amount of sunshine and you have told us none of that. Err on the side of too much capacity.

This JRC website could help you estimate the amount of solar energy you can expect

...R

3

Hi Robin2, thanks for your reply.

The project is the automated chicken coop door

In essence how it works is -

Door mechanisation (Stepping Motor & Geared Motor) is triggered via a light sensor which either opens or closes the door.
This in theory should happen twice a day once in the morning and then again in the evening.

So my question is - Will a 12v battery be able to power the above configuration?

Example of battery to use - Power-Sonic PS1212A for sale online | eBay

or can you please suggest a suitable alternative.

Not sure if this forum can answer this question but let give it a go -

As the chicken coop is not near electricity I need to keep the battery charged via a solar panel.

My understanding is the battery will be used minimally so I think all that needs to be done is keep it topped up?

I am based in Australia so we have plenty of sun power.

Question - What configuration will be needed to achieve this and do I have to do anything on the Arduino side of things.

Thanks
Tony

4

Yes, a 12V lead acid battery will work and be safe. Since lead acid batteries can provide over 14 volts when fully charged, you will need a small voltage regulator to reduce that to 5 or 7-12V for the Arduino.

You may be able to use a small motorcycle battery and a relatively small solar panel to keep it topped up, but the final outcome will depend on all the other components and how frequently the motor is used.

I would not use a stepper. A geared, brushed DC motor is much more efficient and should hold its position when not powered. Consider a linear actuator to open the door. You will need an appropriate motor driver for any motorized solution.

It is easy enough to put in a bigger battery and larger panel if the first attempt doesn't work out.

5

Another alternative for the 12v battery might be a good (i.e. no failed cells) but worn-out car starter battery.

I agree with @jremington - I can see no need for a stepper motor. A DC motor with a worm drive (such as a used car screen wiper motor) will hold its position when the power is disconnected. You can control it from an Arduino with a DPDT relay (also commonly available as a car part). Just note that you will need a transistor between the Arduino and the relay because the coil current in the relay (and the voltage) would be too much for an Arduino.

Use a couple of micro-swiches to identify when the door is fully open and fully closed so the Arduino knows to turn off the motor.

...R